Silly me: I bought a 944 for E-street Autocross
 

Made it back from the purchase in Denver to Alabama without a single issue, other than being stopped by heavy snow in Arkansas. Cruised like a dream between 75 & 80 all the way.

So far, I've replaced the K&N cone intake with the original airbox and removed 25 lbs of sound system amps, sub and wiring. Have belts and the new tensioner tool on the way, etc. (Back in the day I used the Kricket tool, after calibrating it to the Porsche tool.)

So, now I'm looking for some M030 struts I can get revalved and some wheels. I need 17 by 8 and 9, ET 52 and ET 57, or thereabouts. Probably have to go with CCW Classics. There were some 1992/93 968 wheels in that size, but I don't know where they might be found. Probably very rare.

I plan on updating this thread with my progress, in case anyone is interested in this fools errand!

Please feel free to comment/advise!

Here she is: a 1989 in really good shape, only one small dash crack,with the all-important M220 LSD.

Very cool!

I built a car like this. Johntorg has it currently with no engine. Not sure what he left on the car but it had the m030 everything (torsion bars, away bars, struts with the height collars), 16" phonies and a spare set of forged club sports, sport seat, short 5th transaxle with lsd.

Save yourself some very difficult parts hunting and just make him an offer on it!

Finding the 8" and 9" wheels looks like more of an issue than I thought. So, I just ordered some 225/45-15 Rivals S 1.5's for the little 7" wheels I have now.

I'll run those plus a Tarret front sway bar for the first half of the year.

My plan is to lull the rest of E-Street to sleep, then surprise them later.

Yeah, that'll work.

One I had was fun in ES and you could get an insane alignment on the m030 setup. Low, tons of camber, etc. But it still handled like a boat.

Main problem I had was that it killed ball joints on the regular, and since I couldn't run camber plates in ES, I was going through about 3 sets of junkyard upper strut mounts a year. They would blow out the rubber and start contacting the hood under braking!

And why don't you just get some 16" club sports? Are there no good tires in 16 anymore?

There are "ok" 16's, but not optimum. Better 15's, actually.

Be careful with the alignment, specifically the ride height. I was told after the fact that I was running my 968 too low, and as a result its roll center was (literally?) underground.

To this day I don't know exactly what that means, but the guy who told me that has literally decades of Porsche setup experience and is a professional race setup engineer, so it's probably true. :)

Are you sure about that? The biggest wheels that were legal for my much later, heavier, and more powerful 968 M030 were 17" x 7.5" F, 17" x 9" R. I'd be surprised if your earlier 944 came with bigger wheels, but I have no documentation to corroborate or refute that suspicion.

It means low jacking force! :corn:

It's common for people to lower their cars thinking it's faster and REALLY screw up handling something awful.

I think there's a rule that says something to the effect of you can't lower the car to achieve more than 2* of camber in street class. I wasn't really sure on the interpretation of the rule, but at its lowest I think it was capable of something like 2.7* on each corner. I never did wear out my race tires; sold them with the car!

There's no such rule. Adjusting ride height through its entire range is explicitly permitted by 13.8.B:

I just looked at my old notes, and we ran -3.6 degrees on the front of my 968. (Did I mention that we had it pretty low?)

I haven't found an ordering guide, but the widest wheel combo listed for the 944 on WheelCollision.com is 7.5" F / 9" R.

According to here is 16x7/16x7 for a late NA. Only the '88 Turbo S (& 89 turbo) got the 7.5&9.

I found an '87 brochure here.

EDIT:
Hmm, I wonder if this from the PET would be protest proof:

https://cimg0.ibsrv.net/gimg/rennlis...e4b306ae70.jpg

Can you find any proof that M030 was orderable on a 8v car?

So here's the story. See if you guys think it holds water.

First of all, yes, there was M030 for the '89 944. Mostly, but not exactly the same as the Turbo M030. The springs were different, for instance. This is very clear from the 89-91 PET, which specifically limits these M030 parts to the '89 non-turbo, non-S2.

Like all PETs, the 89-91 PET has a list of options in the back. This is clearly not a compendium of all options ever offered as they change from PET to PET. They are specific to the years covered by that PET. M394 is option for the 16 by 8" and 9" magnesium phone dials that were used in the various 944 racing series in several different countries, including the US. Most were turbos, some were S2's, as I recall. I've actually seen one of the 7 US cars for such a series at Trissl in Florence, Alabama. It has these wheels and the offsets are known. It was always a longstanding tradition for Porsche to offer "special" wheels, such as the C2 Turbo wheels, on other cars. C2 Turbo wheels were standard on only one, low-rate model, but were available as options on C2/C4 and 968, for instance. Makes good business sense to increase the rate.

So, if it's in the PET as an option, I say you could have ordered a car with them.

Now, one could argue that I can't prove which year this option became available. Maybe it didn't become available until "90? I think I'm covered there also, because the same option is also in the 86-88 PET. The wheels were first used in 86 on the "race" version cars, so clearly they existed and were optional wheels long before '89. So, if M394 is in the earlier PET, it must have been available in the first year of the later PET.

I haven't researched 968's, but I'm pretty sure the C2 Turbo wheels (17 x 8 & 9) were an option for at least 2 years. I've found it multiple places. I think it was M403, at least on the 911.

The roll center in the front supposedly goes below the ground (at least some smart people think so... I haven't actually seen proof) if the lower control arm becomes less than horizontal. But, guess what? The world doesn't stop spinning if this happens. Nothing goes crazy. Corvettes have both roll centers very close to the ground and sometimes below, especially the front. The sun rises the next day.

Low roll centers are used, in big part, because it minimizes jacking forces. You can actually get anti-jacking with a below-ground roll center, which changes the handling characteristics. J-Rho is on record as saying in many cases he'd rather have the lower CG and live with a little wonky handling.

However, there is a problem with the ball joints of 944's if you go too low. They will bind and break the arm. I never had any trouble with my S2 with the lower arms set horizontal at static load.

Updates:

- Tarret is held for a part that goes into their front sway bar setup. Paragon thinks 3 of 4 weeks before I get my bar. In the meantime, I may be able to get a 968 M030 bar.
- I ordered Porsche-original engine mounts from Pelican. Turns out they are not presently in stock. Waiting for availability info.
-I installed Brisk Racing Lamborghini-Type spark plugs. I used these in the Corvette and got a definite power boost. (Lane Borg did back to back dynos to prove this also.) The Bosch plugs I took out looked fine. I immediately noticed that the idle (and above) was smoother. More power? Maybe. I only got to test drive it with another person, vs. the previous drive with me alone. The car felt basically the same, but had an extra 180 lbs in there, so maybe. But, the engine definitely ran much smoother, indicating more efficient, even combustion.
-I took the phone-dials down to WheelFixit (get it?) to be refinished. They were in pretty bad shape, but not scuffed or curbed. That's where the tires are shipped to as well.

Historically I don't think that would have held water. There's all kinds of stuff listed in PET, and I'd certainly have expected a protest committee to want to see an order guide showing the part.

Theoretically things have changed now that Porsche Exclusive options have been ruled legal, but I'm not sure if this will have any effect in practice. I'd still expect a protest committee to request proof that a car was orderable in that configuration. PET is circumstantial at best, and my understanding is that Exclusive cars weren't very well documented back in the day. Given that, how do you convince the protest committee that those 8" fronts are legal?

My memory is *very* hazy (this was more than a decade ago), but I want to say that the subterranean roll center was being blamed for the massive body roll (and consequent wheelspin) that we encountered.

I'm interested in your spark plug experience. Which Bosch plugs did you and Lane compare them against? How many miles were on them? I've heard (anecdotally) that most times people see improvements from new plugs it's because the old ones were bad, not because the [whatever] was any better than any other new plug. Plugs are certainly a cheap/easy upgrade path if it's true, though.

I agree completely that my experience is not scientific. They were std WR7DC. However, Lane did a back to back dyno test, new NGK (the accepted LS1 standard) vs Brisk and showed 7 lb-ft increase in the midrange.

These Brisks are the type where the tip protrudes and the spark travels sideways and up to whatever side electrode has the easiest (richest) path. People used to "index" spark plugs to get this effect. These are automatically indexed.

I haven't been able to find an "order guide" for those years like we can find for later years. Is that what they were called back then?

I'm doubtful that option 394 would be shown in the regular order guide. I'm thinking it would have been more like today's exclusive options, something you'd have to ask for when you ordered your car. I think in 1989, you could have pointed to the 1986-88 PET and said, I want those wheels on my car. I will continue to try to prove that.

I don't think this option would be comparable to "special wishes" where just about anything goes if you had the money. This was a wheel that was made in the hundreds if not thousands and have come up for sale from time to time. It was given a regular option number in two different PETs. I saw video of a race in France that had nearly 50 entries, all on this wheel and these races went on for 3 or 4 years in various countries.

Update:

Measured the sway bars. Some previous owner put the M030's on it, which is really good because the 18mm rear bar was proving difficult to find.

Got the 7" phone dials refinished and put the new 225/45-15 Rival S 1.5 on them. I measured them at 22 and 5/8" diameter with 36 psi sitting flat on the ground. The gearing difference is very noticeable as compared to the ~25" tires that came off it. This is what I'll run for now until I have more proof that wider wheels are legal.

Installed SS braided brake lines. (Legal for a car this old.) The end fittings on the originals were quite corroded, as are the calipers. Really lucky I didn't ruin a hard-line, especially since it required an 11mm flare nut wrench, which I didn't happen to have and no one carries locally. I borrowed one after the first corner.

Last thing I really have to do before the first event (less than 2 weeks) is put the stock chip back into the DME. There will still be a couple of things "slightly" illegal that I'll discuss with my competitors.

Oh yeah, I need to dial-up some negative camber, too!

Nice!

its definitely the coolest ES car. Who wants a Miata or mr2 anyways?

Looking good Ed!

Something I've always wanted to scam - how long are the OE bump stops? If they're long enough, on a height adjustable car, you can legally get whatever spring rate you want in Street by making the "bump stop" a spring. Circle track roundy rounders have some pretty trick stuff.


https://cimg3.ibsrv.net/gimg/rennlis...93da1f1865.png


Anything from stackable modular pieces of varying density and shape:

https://cimg9.ibsrv.net/gimg/rennlis...640f370b92.jpg

To flat out coil springs as bump stops:

https://cimg7.ibsrv.net/gimg/rennlis...39a96849ba.jpg

Since I got hit with Deja Vu while typing this, looks like we've already discussed this here.

The front bump stops are substantial, but not as tall as on the 986. The rears are pretty short, at least on the std shocks. I've never seen a rear sport shock, but I assume it's a Koni sport yellow?

I may be wrong, but I don't think they were designed to augment the other springs like they were in the 986/996.

edit: I verified with the shop manual (I just received) that the M030 rear shocks were Koni sport yellows. They have bump stops called an "auxiliary rubber spring" which length appears to be about half of the available total rear shock stroke. Given that the car will compress the shock most of half way just sitting there, I think it might be possible after all to use the front and rear bump stops as you (and I) have suggested. I'll probably leave that for next year.

Alignment update

Going for max negative camber, front and rear.

After a first try, I've now got 2.5 and 2.25 degrees in front, left to right, zero toe, steering wheel centered. It started with 1 and .5 cambers and zero toe. My stock front is pretty high. Once I get the sport struts in there and the front end down a bit I expect to get 3 degrees, as others like Knfeparty have stated.

The rear was more of a problem. The right side didn't want to move. Took some chemical and dynamic persuasion. Started with .25 and 0 cambers and zero toe. In the end I had 1.75 degrees camber on the left but only .75 on the right and I'm not sure why. And I over-did the RR toe, ending up with 3/16 total toe-in, more than I think I want.

Now that I understand how it all works I figure another try at the RR will improve things. That will have to wait until the stock chip is back in.

edit: took another whack at the RR adjustment this morning and it moved some more. Now have 1-3/4 deg negative camber both sides and 1/8" total toe in. Close enough for guvment work.

Gotta love these old cars that had adjustability!

I just found my 1988 Porsche fact Book and price book that lists standard equipment and options that can be ordered. It looks like option code 393 could ordered for a regular 944. 8/9jx16 "disc type" rims for $3540. LSD, sport shocks and M030 are also listed as orderable.

Wow awesome find! What's 637?

WooHoo!

637 = "Performance Handling Package"

Not sure what this means, and I really need the same thing for 1989. One just sold on e-bay for $26

edit: Uh-oh. I found a picture of the 1989 Factbook on eBay. Options 393 and 394 are not listed there.
edit2: actually, what I found was a little fold-out pamphlet. There's a 98-page, internal sale brochure that seems likely to be the authority.
edit3: I found the fold out for 1987. It doesn't have 393 or 394 either. Does have 637 available for the standard 944.

I'm confused. Hard to believe that two different wheel options were 1-year only.
The way I would read the '88 data is that both 393 and 394 were wheel options that only came with the performance handling package, 637, which was probably sport suspension plus wider wheels and maybe some other stuff, and was limited to the 944S and Turbo. Not clear to me that the regular 944 in 1988 could get those wheels.

637 was Club Sport Edition in 1988 and could only be added to 944S or Turbo. 637 price was listed as TBA. The 393 could be added to any but cost less for the Turbo ( already had 8/9x16). I think they mean that 393 was included with 637 option but 637 could only be ordered for 944S or Turbo. Clear as mud.

I got the Fact Book and the Price List when I bought my used 1988 Carrera. It has been useful and I don't think too many are around. It covers all 1988 Porsche models.

So, 394 would be the similar? Orderable for any 944. The reason I ask is because I've seen other info that the 393 wasn't actually 8/9, but was really 7.5/9, whereas I have absolute proof that the 394 was 8/9.

I may have to buy a 1988.

As far as I can tell, option 394 is 8/9x16 Phone Dial forged Magnesium wheels as used on the 944 Turbo Cup.
According to another source: In 1988-9 The 393 option is 7?/9x16 D90 (design 90) wheels.
951 362 115 30 - alloy wheel 7 J x 16 - ET 65 - FORGED silver
928 362 119 30 - alloy wheel 9 J x 16 - ET 60 - FORGED silver
For 1990 the S2 and Turbo wheels were different D90s
928 362 114 05 - alloy wheel 7,5 J x 16 - ET 65 - silver
928 362 118 05 - alloy wheel 9 J x 16 - ET 52,3 - silver

So maybe the book is wrong in saying that the 393 is 8/9x16. As long as you could have ordered the 394 option for a regular 944 then it would be legal.

D90 pic:

Thanks.

I think what you've found is sufficient proof to withstand any protest for 8/9 on a 1988 944. It really does look like it was a one year option. I guess they needed a few more orders of those magnesium phone-dials, maybe to fulfill a contract requirement. Who knows?

this photo isn't of D90 wheels, which are a cast wheel and made by Ronal ( I believe).

The photo is of Club Sport FUCHS wheels, which are forged aluminum and came on the '88.2 turbo S and '89 951

You need to look at the differences of these two wheels and feel their weight differential.

Design 90 wheels may look slightly like a Club Sport Forged FUCHS but they are no where near the same in structural strength. Absolute look. Or wheel width, structure, and fitment. They come from two different manufacturers and have entirely different costs; new cost as well as current values.

They have different part numbers

D90's are heavy! They came on my old S2

I knew there were forged Fuchs versions and cast Ronal versions but I thought they were lumped together as D90 type wheels as they look fairly similar. I did list the different part numbers for the forged and cast wheels. I'm sure mrgreenjeans is entirely correct. Was Frank Zappa your son?

Many do consider them as 2 D90 variants... they can be a little difficult to tell apart in non-close pictures. The "eyebrows" denote the forged clubsports.

I had those forged clubsports and ran them without protest, but I never did any tour events back then either. I can attest that they are a badass lightweight wheel.

After my first autocross with the car today, I don't think 7's & 9's is going to cut it. The car has issues.

It was a tough day. I was 3rd of 7 in ES, 1.3s out of 1st on a 65s course and only paxed 29th of 112.

As it stands, the car has M030 front and rear sway bars, but the springs & shocks are standard. I was running the new version of the Rivals S on 7's, which I really liked. This tire is easier to drive than the RE71R. I couldn't comment on total grip. I experimented a bit, but ended up starting each run with 31 psi in front and 34 in the back. Any less in the back and the tire was rolling over just too much.

The car was a handful. While the front end was quite responsive, it's the rear that was the problem. When the car really leans over, suddenly something weird happens to the trailing arm geometry/tire patch/camber or something and it wants to snap-oversteer. At present, the car cannot use all the grip even these little tires will provide.

Given the high-polar moment, making things happen relatively slowly, I was always able to catch it, but it was disconcerting. By the end of the day I was throwing it into a corner, letting the weird oversteer thing get started, then applying full power to settle the back end back down. That was working pretty good and is only possible because the LSD was doing it's job well.

I'm going to hope that the sport springs (plus a bunch more damping) is going to help this issue by limiting roll and pitch.

I'd sure like to know if this behavior rings a bell with those who've been down this path before?

What's your rear toe? That sounds like toe-out behavior. Do you need to crank in a ton of toe-in to prevent dynamic toe-out?

It's got 1/8" total toe-in in the rear. The back-end seems stable until this particular state is encountered. Toe-out may very well be occurring dynamically.

I think I remember an article by Jim Pasha(?) that the 928 would do this also, even with the 928 toe-control design, and he solved it with the spring & damper set he helped develop many years ago.

I suspect that this is probably just a typical, large-motion semi-trailing arm behavior. It may be what led to the old saying "slow-in, fast-out", in that by braking early (in a more or less straight line) for a corner and then powering thru it, this particular state of the rear suspension is not encountered. (I always thought that way of driving was more suited to the rear-engine 911's, but maybe it really had as much to do with the suspension design.) Being used to double a-arm I don't typically do this. I never raced the 944S2 I had previously, only a couple of track days which were driven sedately.

Also, the old saying "Any suspension design will work as long as you don't let it." may apply here. Just don't let it move so much (with higher spring/roll rates) and the problem will go away.

I don't recall experiencing anything similar with my 968, so I'd guess that a) there's something wonky with your car, or b) we had everything cranked down hard enough to mask any weird suspension behavior.

The biggest difference I see between my old setup and yours is that we were running a much bigger 1.25" custom front bar. We still had gargantuan body roll even with that bar, though, so I'm a bit skeptical that (b) is the explanation.

To sjfehr's toe point: I didn't save most of my notes from back then, but the last one I have on toe is that we were running 1/32" of toe-in in back (i.e. for all intents and purposes zero). That suggests that your problem isn't too little toe-in either.

Thanks for the info. Another good possibility I thought of later is a perished bushing or two in the rear. The front suspension bushings are all new, though not M030, but the rears may be 27 years old.

The rears don't get much love. Also look at the trans mount and shifter bushings when you are there.

Sounds familiar. Mine was more of an off-throttle oversteer disaster. As you described, being flat on the gas solved most all problems.

The m030 springs and torsion bars should help you out, but even those are still relatively soft.

I would definitely check out all the bushings.

Tire pressures seem a bit high for how light the 944 is, but tire rollover is tire rollover.

frank zappa was my grand dad

son of a-nodder mater with a space alien peder


and no, the D90 are not referred to across the board covering both wheels. This is the terminology sellers with those rims wish to propagate, as there is moolah to be made by confusing the two.

Also, am sure the cast D90s aren't Ronals, but a different maker. Just can't think who they are right now. I don't have any in my group so cannot go out to the cars and look either.

But, the forged, light, and strong ClubSports are definitely ONLY made by FUCHS and carry the price accordingly.

Got to the bottom of the 8" & 9" wheel question.

Attached is page 26 from the 1988 order guide.

The '88 guide indicates option 393 and option 394 (specifically the 8" & 9" cast magnesium wheels) were available, but only for Option 637 "club-sport" cars. These were the Cup cars used in various race series in different countries. There is no indication that these wheels were available any other way than by ordering a Cup car.

M030 Parts
 

Made a trip to Birmingham yesterday to acquire some M030 parts I need.

-Brand new, in the box, late M030 struts, rebuilt/revalved and converted to double-adjustable by Koni. (The spring perches, threaded collars and locking nuts are still available from Porsche.)
-A pair of used M030 upper strut mounts
-The correct blue dot/white dot front springs (whew, was I sweating finding those!)
-A pair of 3-race JRZ single-adjustable shocks for the rear. (I may need to fab a spacer to set it at the correct position w/r/t the lower control arm mounting point.)

The seller also has a pair of used 25.5mm torsion bars for the rear that he gave me good price for that I will get later.

M030 bits are coming together.

I think that double adjustable shocks will take you out of Street Class with SCCA. Looks like a nice setup though. Permanently disabling the second adjuster could make it legal.

Double-adjustable shocks are both legal and common in Street class.. My iPad won't let me copy the text of the rule, but you can see it in 13.5.A.1 here: http://cdn.growassets.net/user_files...pdf?1484692275.

There's an outfit that can widen 7" phone dials, or Fuchs.. That's probably how I'll get 15 x 8's in the rear, now that Ive confirmed what Pedalfaster knew all along about legal wheel sizes.

I love phone-dials. I don't care if they aren't the lightest. Need to find 2 more 15 x 7's.

I should have read the rules again before posting. It was triple adjustables that were not allowed.

There should be some 15x8 Fuchs around. My 911 came with 15x7&8 Fuchs. Sorry, they are staying with this car. I haven't checked the going prices though. BBS made 15s and 16s in those widths. I think the widest Cookies were 7". I have a set of those and they are light. Can they be widened?

i think those will all be early offsets where I need late.

The simple technique of extending the barrel of a wheel will increase the offset by half the amount extended, then requiring a spacer to get back to within 7mm of the nominal stock offset. If I'm thinking right?

If I start with a 7" 52.3mm offset wheel and add 25.4mm to the barrel, I now have 12.7 mm too much offset.
Then I'd need a 6mm spacer to get back to within 7mm of stock. Seems like that might work? I know there's plenty of space. Might need extended studs.

Phil's had some 15" Jongbloed wheels made up for 944s, but I can't seem to find them now. Maybe a wild goose chase, but maybe they were what you need?

Yes, I found those. They seem to be good, economical wheels, but they have a reduced offset to 40mm, in order to push them out, I guess. I can't see how they can be legal.

83 944 NA in CSP
 

Hey, I've just participated in the last half of SCCA solo here in CSP.

Weltmeister 225lb/koni sport/25.5mm sway/poly bushings
26mm Torsion/koni sport/18mm sway/poly-graphite bushings
Upper Strut bar in front
Sway mount reinforcement brackets in front
Steel arms not boxed yet
Removed rear bump stops
Cut front bump stops by 50%

16" 7" and 8"? early offset Phone Dials with Nexen SUR4s and 4mm spacers.

Not sure what your experiences have been, but even with stiffer rate springs...my car would fully compress down to the bump stops and that would upset the geometry causing unsettling understeer and oversteer. You might want to double check your travel and stops. I think early 944's like mine had a 3-4" rear stop so you may not have the same deal.

My set up is a slightly stiffer set up of a late turbo, as I could not afford the higher aftermarket sway set up. I opted to put in a VEMs and SuperCharger instead since mine is "not stock" class.

Where do you run?

I think I'm going to get real knowledgeable about bump stops.

I went to install the JRZ rears the other day and found that one of them was wonky. No gas pressure... strange behavior. It's being looked at. N2 may have gone past the floating piston o-ring.

2nd event
 

Only change on the car since the first event is 7mm wheel spacers all around. When I get the rear wheels widened to 8" these will make the offset legal.

Conditions were very wet, with standing puddles, and I was loving it. I felt like Alonso getting his chance at Vettel and Hamilton (represented by two brothers in a "99 Sport Miata who were 1 and 2 at the last event) thanks to the water, and I was right, as long as it lasted.

After my 4-run morning session I was 1st in ES and 1st in PAX among the half of the classes that had run. With the low grip level the car was well-behaved, given the lessor roll it had to deal with.

Then it began drying out and the 2nd run group took over all the top PAX positions.

During lunch it rained some more, then was drying as our group began our second set of 4 runs. The more grip improved the more the ES competition crept up on me. I got passed by 3 others in Miatas and ended up 4th, with the top 4 being very closely spaced. I felt pretty good because winning ES was very possible today.

It also makes me more certain that, once the car is lower, stiffer and better damped with the sport suspension underneath it I'll be able to do well locally in ES.

Too soon to tell about national competitiveness.

P.S. I'll be in an AS Corvette Grandsport at the Blytheville Pro in 2 weeks.

Last major piece needed
 

The last major piece of the M030 suspension I need are the threaded sleeves that slip down the Koni strut that provide height adjustment.

Anyone have idea where I might find a pair?

I've contacted 944ecology and Paragon with no luck so far.

I don't have a part number?

Have you tried GroudControls site, they offer the different combos of coil over threaded collars kits for the 944.

There is a Hawaii Region of SCCA Solo here, that's all we got on the island of Oahu. The courses are short avg 40sec and do have hair pin turns due to the smaller lot than other scca folks have. We only max out 2nd gear, never get in 3rd.

I was also going to recommend getting aftermarket pieces, if not necessarily Ground Control, since aftermarket shocks (and threaded shock bodies) are legal.

This is actually a gray area, though. Since the sleeves aren't technically part of the shocks, it's not unreasonable to assert that you must run the stock sleeves. Then again, I'm pretty sure we didn't on my old 968 (as we had Motons with threaded bodies).

You're seeing one of the downsides of running a 27-year-old car with a rare option package. Maybe watch eBay and the PCA classifieds?

Good news: I have two sets of stock sleeves, spring perches and lock rings on the way. Somewhat beat up with some thread damage, but I think they will be serviceable with a little work.

I've already got new perches and lock rings on order from Porsche, so I'll have some extra parts.

As for perfect legality, I was prepared to go with an aftermarket solution but I think it would have to do 2 things to be legal and protest proof: 1) not be significantly lighter, and 2) not provide any extra range of adjustment. I would have to make sure I knew what the stock range of adjustment was, especially how low it could go, by measuring a stock assy, and be prepared to prove with pictures and measurements that I was not exceeding it.

For instance, the sleeves in the kits that are sold to convert standard struts to adjustable coil-overs appear to be a bit thinner material, but I'm not sure. Also, they definitely use a different type of thread that doesn't require a separate spring perch and locking ring. Therefore, the assembly is clearly somewhat lighter and might offer additional lowering capability. They are also designed to use racing springs with square-ground ends. Not sure how I was going to adapt to the Porsche spring with unground ends and variable wire diameter.

The other solution I was contemplating came from George Beuselinck at 944Ecology. He was willing to temporarily "sell" me a sleeve off a set of M030 struts he had tucked away so that I could reverse engineer it and have a set machined from scratch. That was quite a generous offer from someone I've never met.

Thanks to everyone for their help and comments to date!

P.S. with an aftermarket strut like the Motons were(?), since the strut is a suspension link, not just a shock, I'd think you might have to prove both things as well: no weight (performance) advantage and no adjustability advantage.

I'm pretty sure the weight consideration is a non-issue. 13.5 says:

Several paragraphs of restrictions follow. As you noted, suspension geometry changes as a result of the strut substitution are explicitly forbidden, but there's no mention of weight. Pretty much everyone serious runs aftermarket struts, and this is the first time I've heard anyone mention weight as a consideration for legality. I don't think it is.

Interesting, and it never occurred to me.

Given this, I could design a legal strut from carbon fiber and Ti and take big weight out of the front of any McStrut car. (At incredible expense, of course.)

I have a 944S and I'm running in C Street. Having read the rules a few times now it appears to require that I install all the M030 components if I want to install any of them. As an option package, it specifically states that I must install the entire option package and not just part of it.

Are you installing the M030 spindles and brakes too?

One more question.

I'm running autocross on BFG 225/45-15 on the original 15x7 phone dials too. I definitely have noticed that I could use some more traction in the rear in the turns, slaloms, and exiting tight corners. I don't have LSD :-(

You mention there is a source for modifying the original 15x7 phone dials to 15x8 for the rear. Who offers that service?

I was referred to this guy http://www.weldcraftwheels.com

He said his backlog was 8 weeks but would shrink to 2 or 3 later in the summer.

it is true that option conversions must be complete. My reading of the 89-91 PET indicates that only the turbo got different hubs and spidles with the M030. The base and S2 did not. Also, the base didnt get different calipers like the S2 and turbo got.

I havent researched the earlier S.

Edit: Per the PET, the '87 944S M030 spindle (951.341.655 (656).34) became the standard spindle on the '89 Base. So, it maybe makes sense that they wouldn't have needed a new M030 spindle for a slower, lighter, less powerful car.

I have no idea what the difference is between the '87 standard spindle and the M030 version. If the difference was negligible, or negative, in autocross terms your competitors might not care. For instance, if the M030 gives more camber, or is only slightly heavier for durability, etc.

Oh hey, Weldcraft did mine, so that might have been me.

http://strcarrera.blogspot.com/2015/...ls-part-2.html

I actually got the referral from someone else, but really cool to see your results.

Did you ever sell that car? I think it was on BAT at one time.

Wow. Just... wow. Speaking as an engineer, there so so many reasons NOT to do that no matter how good the welds.

I've been skeptical too, but many of his customers are road-racers and the products seem to hold up.

My experience with weld repairs cracking is that the new crack develops a slow leak first which is catchable early, rather than a catastrophic failure. It's happened to me twice.

If I were regularly tracking such wheels, I think I'd dye-penetrant inspect on a schedule.

Nope still have the car and the 9" front wheels.

M030 struts going in. You can see the blue/white dot spring, which has 2 diameter transitions, both coil diameter and wire diameter change. A bit of the Tarret front sway bar is also visible.

For now, that's the stock bump stop.

Wow wire diameter change? That sounds really expensive, is that common in the OEM?

According to Carroll Smith in Tune To Win, Porsche was the first to do it for racing.

Machine the dia. change first, then coil it.

I have no idea how common it is. That's why I had to find those specific springs to be legal.

The wire gets thinner at the top and larger coil diameter, both making the upper part softer. It also allows the standard upper perch to be used.

New, M030 "green dot" front control arm caster mount vs. stock.

More rubber, not less! and a different, much cheaper, design. The stock has cut-outs in the rubber that would seem to allow more flex.

Update: I'm pretty sure that what was on there was not "stock", but the later 968 design that had much less rubber.

This is what it looks like with the M030 front struts set as low as they will go.
Definitely some rake now, when it had become close to flat once I put all the camber in.

The front Konis are set in the middle (bump and rebound), borrowed Bilstein HD rears have more low-speed damping in both directions than stock and more than Koni Sport in bump (issues with the JRZs not all worked out yet) got the Tarrett front bar and the M030 20mm rear bar. Car is definitely stiffer.

Tomorrow I will raise the front a bit, probably about 1/4", just to be safe, and autocross it Sunday. Supposed to rain/storm, so I imagine I'll move the struts to full soft.

I've got the torsion bars for the rear in hand, now. I need to find the best possible write-up of how to index new bars to try to get it right the first time.

Not sure how the 944 rear works, but on the 911 I put an angle gauge (phone app actually) on the spring plate. There used to be a calculator tool that told you the angle for the desired height but it seems to have been lost to the ages. If you measure the angle the old ones produce you can probably guess pretty darn close with the new bars. At least you can get them equal height easily this way. How much stiffer are the M030 bars?

Also don't know if it's useful, but the 245-15 Rival S is now in stock at TR. Mine showed up yesterday.

I think 911/944 are pretty similar.

The 25.5 bar should be 38.6% stiffer than the 23.5

Tiny Rivals team member #2.

Do you have the 225's in front? I have a worn set of previous gen Rivals that are all 225's. I too have been waiting for the 245's for my 7&8x15 Fuchs. They are SHORT! Any impressions on performance yet?

225/245 on 15x7/15x9. Running them tomorrow, but on a crappy lot & it's supposed to rain.

So far, on concrete at least, other testing seems to be showing they're very similar or even slightly better speed wise to the RE71r, but much more tolerant of overdriving.

Cool!

I have a friend who keeps commenting on how small my wheels look.

Once you get the new tbars in you'll be able to get the whole car really low if you want to. Mine was pretty slammed (see my profile pic for reference)

Saw you're registered for Bristol; I'm registered in AS right now but I'm awful tempted to buy a plane ticket and try to bum a codrive with you instead of towing it all the way up there!

I've already offered my seat to someone else. Not sure if he registered, however...

This shifting to 3rd is difficult! (Actually, it's the downshift back to 2nd that's tricky.)

Last weekend I beat one of the Miatas that beat me previously, but still lost to the brothers in the '99 Sport. But, I was closer. And data shows that on my fast run I made a mistake that I hadn't made previously that might have cost me the win.

For this last race I had both sway bars in, the M030 front springs and Koni struts, a set of borrowed Bilstein HDs for the rear, and stock torsion bars. You'd think this would be awful, but it was better than previously. I didn't have the front sway too stiff.

A front wheel bearing got noisy. Installing new ones now.

Next week I tackle the torsion bar swap.

And I am seriously researching bumpstops and bumpstop tuning techniques. The JRZ's (still a work in progress) have to have serious bumpstops that limit the travel to keep from self-destructing, so I'm doing the bumpstop thing sooner rather than later.

Initial Goal Achieved
 

I finally won ES in my local region today, driving the 944 and beating both of the brothers in the '99 Sport Miata for the first time.

One or the other brother had taken the win in each of the first 3 events and 3rd was the best I'd done to date.

2 reasons stand out:

1) Yesterday we put on an advanced autocross driving school, headed up by Steve Brollier. (Steve has 4 Solo championships and 9 Pro-Solo.) The brothers were students in the school, while I was an instructor. The funny thing is, I think I got more out of it than they did, even though I didn't really get to practice the drills, just ride with the students and give feedback. This morning I was able to walk the course 3 times, develop a good driving plan, and put the lessons to work. (I didn't instruct the brothers. We joked about how it would be a conflict of interest!)

2) The car has been uncomfortably loose, so I got up early this morning and measured the rear toe. It was slightly toe-out. When last checked it was slightly toe-in. After all the disassembling and assembling I've done lately, this wasn't too surprising. I dialed in some negative toe and the car was much more stable. With the Tarret front sway bar set to full stiff the car is rolling a lot less and I was able to lower the rear tire pressures. Grip was increased and, for the very first time, the chassis could take all the grip that the tires were delivering without immediately going bonkers.

Still a lot more work to do and some key parts to install, but the car (and the driver) are getting faster. Lack of damping in the rear borrowed Bilsteins is causing the back end to actually start hopping up and down during max cornering at the location of highest grip on our site. (Where there's no sealant.) The JRZs + M030 torsion bars should fix that.

Belts
 

Doing the timing and balance shaft belts.

New timing belt is in and tensioned. The existing balance shaft belt I found to be off one tooth at TDC, but only the upper shaft pulley. See pic.

Edit: Got the car back on the road. Yup, engine a little bit smoother than it was before.

Now, I'm dropping the rear suspension to install the M030 torsion bars, bushings, and the super-secret bump stops!

Where did you find the blue dot/white dot springs? I've been checking eBay, but most springs have been early 944 and not from a M030 optioned car.

I've been thinking about going to one of those 944 part-out yards to see if I get lucky, but it seems like a total shot in the dark.

I am seriously questioning the legitimacy of these rules that say we must use 30+ year old springs and offer no replacement alternatives.

That's why they sunset cars in Street after 30 years. Still legal locally, but not nationally.

It's not the SCCAs problem to provide alternatives for all the stock parts that go out of production. Heck, if the ABS module on my MY2000 Corvette goes out there's absolutely nothing to be done.

I got my springs from a guy that now races a 944S2. At one time he'd had a turbo that used them.

Now that I know about the 944 Facebook forums that form the major markets for used 944 parts, I bet I could get another set in a day or two. Forget Ebay. My experience is that everything you could ever want is available from these guys that buy up parts and cars for resale.

Ed, are you bringing the car to Lincoln in two months?

There's a set on my old 944 that johntorg has for sale. I think he still has the car. It had m030 everything even the tbars

Doubtful. Once back together I suspect it will be nearly undrivable for a while as I work out the tuning.

You are running out of eligibility chances.

I think the car is eligible until the end of 2019, so it could go to Nationals 2 times after this year.

"through the end of the 30th calendar year after the manufacturer-designated model year of the car."

So, I think that means 1989+30 = end of 2019

Does this seem right?

Not sure, but I think you should come to Lincoln this year just in case. ;)

Agreed. burglar will help you sort out your wacky handling on the test and tune course. :)

Yeah because I did a great job with the 911. ( Unless that was the joke.)

Nah, I was just volunteering you as the only guy on this thread who's definitely going to be at Lincoln.

Ed, I don't share your pessimism -- the changes you're making aren't that radical, are they?

It's the bump stop thing that may take some sorting out. I gotta get with it and get this thing back together...

On another note, I've been thinking, reading, testing shock stuff on the BS Corvette that was returned to stock and not yet sold.

I threw the Ohlins back on it with a mod that I thought might make them silent, after we put them on a dyno to try to figure out what was making noise. We could see the teflon-lined spherical joint deforming and decided that the metal dust cap was hitting the shock body. But, the 'fix' didn't work. They were quiet when first put on, but made more noise as the miles accumulated, just like before. Very mysterious.

Anyway, I tried high compression damping (what I used to race it at) and very low rebound, lower than I'd ever run, I mean sooooft, both in front and back. (Still autocross alignment, stock front sway bar.) These Ohlins have good compression damping at only 1 in/s, then blow off, so the transient response was still good. The rebound is linear with a broad range of adjustment.

The increase in grip with 3rd rank tires (old RE760) was pretty amazing, even on the street, compared to the stock 14K mile shocks I'd put back on, and especially on our somewhat bumpy autocross site.

I did this after reading Jan Zuijdijk's book, which has got to be the worst written and translated book ever published in English. (He's the Z in JRZ and was Koni's development/race man for many years.) I'm now a real believer in relatively low rebound damping, i.e. no more than necessary to control the springs. Let the car move, but keep the tires on the pavement. Dennis Grant preaches this as well.
In any production car with stock springs, they are so soft that very little rebound damping is actually required.

I was re-reading J.Z.'s book because I'd bought some single-adjustable monotube JRZ's (no remote reservoir) for the rear of the Porsche. We had set them to 125 psi gas pressure. Then I re-read the book and he claimed (3 separate places!) that they needed 25 bar (= 360 psi!) or they wouldn't develop proper compression damping because it wouldn't develop enough delta-P across the piston. I thought about that a while until I was sure I understood exactly how a monotube works in compression, then went back to my shock guy.

He was very nice, had also read the book, said J.Z. was wrong, but, hey, let's go test it! So we did.

We retested the baseline 125psi and got exactly the same curve as he'd given me before. Then we upped it to 250 psi. Zero increase in compression damping at any shaft velocity.

My shock guy says that, so far, he's never seen a monotube that needed more gas pressure than whatever level is required to prevent cavitation under worst-case compression conditions, which can vary, depending on how it's valved. More gas pressure than that does not improve compression damping, in spite of what J.Z. wrote. He says my shocks only 'need' 75 psi to prevent cavitation, as presently valved.

It was also pretty amazing how hot the shock was when we took it off the dyno, even though the rebound was adjusted to the minimum and we didn't run it for long.

I'll be at Lincoln this year, too (AS), and am always happy to drive other people's cars at the TnT! :D

New Blog post
 

I just posted some new info on where I am on lowering the 944 and the effects.

It discusses weight transfer, roll centers, jacking force... you know, all that stuff you think about every day.


https://edfishjr.com/2017/11/29/auto...s-of-lowering/


edit: link fixed per PedalFaster

FYI, the link you provided doesn't work. Try this one: https://edfishjr.com/2017/11/29/auto...s-of-lowering/.

Thanks!

It just occurred to my why messing with the suspension on the 944/924/968 can produce such wonky results: the effects of lowering front vs rear are opposite w/r/t roll stiffness.

The MacPherson front gets softer in roll as the car is lowered. The blog post linked above explains why.

The semi-trailing arm rear gets stiffer in roll as the car is lowered. This is because the semi-trailing arm roll center is very stable with rear suspension articulation, but the CG is being lowered. Therefore, the moment arm is getting shorter so the car rolls less in the rear for the same lateral-g input.

So, just lowering the front and rear equally seriously messes with the roll stiffness distribution and can produce a large tendency toward oversteer without doing anything else! (911's should react similarly.)

This also explains why the jacked up rear ends of U.S. cars, as delivered, supposedly for bumper height reasons, would have produced a tendency to understeer as compared to ROW cars.

That is information that is both relevant to my interests, and also helps explain some of the results I've had.

I noticed that when a 944 is slightly raked....even the slightest...it introduces some considerable roll.

Once this thing gets back on the road I'm going to try to measure roll under different conditions. We'll have a test and tune in not too long where I can go around a skidpad with a digital level taped to the dash and see what I get. Not sure how that will work.

If you want to try it, here's one possible way: measure the roll with the rear set all the way down vs. all the way up. If I'm right about how the rear suspension works, the car will be stiffer (roll less) with the rear end low and roll more with it high. (This is the opposite of the front end.)

What I'm saying is that, say we start with both ends of the car hiked up and the car level, i.e. no rake. As we lower both ends, keeping the car level, the front gets softer in roll and the rear gets stiffer in roll. This will move the handling balance from understeer toward oversteer as the lateral load is "attracted" to the stiffer end of the car.

By the same token, if you start with a car that's level and lower just the front, creating positive rake, it will roll more. And vice-versus.

Yes I started it level and slightly lowered (1.75") with 250lb weltmeister springs and 26mm CIP1 torsions adjusted down with the most minimal pre-load. As the front settled, the roll increased..so I re-adjusted the rear to level out again....this corrected the added roll.

I tried a lower stance and loved it on the track, I think it was about 3.5" pretty low but handling was actually predicable... given the track is smooth and flat. Street wise it was not comfortable and did not pass our annual inspection in Hawaii so I raised it back up to the 1.75" front and leveled the rear. :( I may take it down another .5" all around.
I just have all poly bushings and turbo sways front and rear. upper strut and C-pillar bar since I'm already in SCCA SM due to other mods.

The digital level won't give you reliable roll numbers due to lateral g-forces. It will only work at rest. You may have better luck setting up a camera to measure roll from the stills.

I kept trying to edit my post (it said I was still logged in, but I wasn't) to include a clear statement that I thought you were absolutely right: anything that creates positive rake makes the car softer.

Where do you take the 1.75" and 3.5" measurements from?

Oh. Yeah.

My bad.

https://cimg0.ibsrv.net/gimg/rennlis...2f4d0039ad.jpg

Both wheels, back to back
https://cimg1.ibsrv.net/gimg/rennlis...0d8459c020.jpg

end weld of the added 1" strip

Got my widened phone-dials back from Weldcraft today... now 8" wide.
245/40-15 Rival S tires should arrive tomorrow.

Soooooo what i take from this... is I should maybe run just a little nose high? being a little more neutral with the ability to hit oversteer would be fantastic. I did notice an improvement when leveling my s2 vs is previous stance now that i think about it. It was lowered all around but down in the nose a little bit, i brought it back to level and its less twitchy out back...

Edit: i don't know if this helps your research at all, but this is the raw video from an event i did a few years ago that just tracks the front left wheel. Cars on koni yellow inserts, 968 M030 bars and -1.5 camber. 225/45/17 and 255/45/17 stagger. I just dumped the raw footage, so the action is from :30 to 1:40. Also my sd card was going bad so there are glitches.

I don't think one can say anything absolutely about how to rake the car. It will depend on what springs, what sway bars, what tires, what adjustability you have (M030 or not) etc. The rate at which the front loses stiffness in roll as it's lowered doesn't match the rate at which the rear gains stiffness as it's lowered or loses it as it's raised. I think with the 968 M030 bars you are probably best as level since this is a Porsche developed combo. For autocross, you could probably use an even stiffer front bar rather than raising the front.

A completely stock, non-M030 car? I'd say you probably want it level as Porsche seems to have intended. I would add a stiffer front sway bar long before I lowered the rear to produce negative rake. Then, toe-out the front tires to quicken the turn-in (easily restored once the event is over by counting flats or other marks) and adjust over/understeer balance at autocross speeds with rear toe adjustments. Not that you need this, but general caveat: when the rear-end is lively at autocross speeds it may be too unstable at higher, track speeds as the car tends toward more oversteer as speed increases.

As for the video, it doesn't seem to me like you have excessive roll based on how much the tire moved within the wheel-well. Of course, stiffer is generally better for autocross. Nice downshift into the hairpin!

https://cimg8.ibsrv.net/gimg/rennlis...76d3acde37.jpg

245 on 8 (left) and the tread measures (from overhead) exactly 1" wider than 225 on 7.

https://cimg1.ibsrv.net/gimg/rennlis...ae49a073c5.jpg
https://cimg0.ibsrv.net/gimg/rennlis...f38dbfa5cc.jpg


Back to preparing the 944 for autocross this year, last year of national eligibility.

I dropped the torsion bar carrier so I can put in the M030 bars and replace all the bushings. The bars that are in there were found to be the standard ones. The M030 bars will be 38% stiffer.
First pic is the inner end of the trailing arm showing new, sport hardness bushings installed, Below that is the end of the torsion carrier cap showing the std rubber bushing in place. No M030 variant was used.
Second pic is the T-bar spring plate assembly, cleaned & painted, with new rubber donuts superglued in place. These are stock Porsche, no M030 variants were used.

I will reassemble and index the T-bar. I'm doing one side at a time, per the procedure I found. We will see if this procedure gets it right the first time as it claims to do.

Got the left side reassembled with the (hopefully) correctly indexed new torsion bar. Right side was disassembled today and bushings coming out/going in.
https://cimg4.ibsrv.net/gimg/rennlis...cab65594a7.jpg

In the next pic you can see a measuring tape hanging from the banana arm. The method I'm using allows me to calculate a new dimension from there down to the center of the drive based on how much lowering is wanted and the new T-bar diameter. I figured out that I could place the trailing arm in position first without the "snout" that carries the T-bar splines in place. Then you can bring the snout into position over the T-bar with the spring plate on the outside of the trailing arm as shown here.
Notice the big black rubber donuts on the "snout."
Index the T-bar and snout until the spring plate fastener holes line up on the trailing arm.
Then remove the trailing arm and drive the snout the rest of the way on, assemble the cap, then bring the trailing arm back and the spring plate will be on the inside like in the picture above.
This allows the snout with it's bushings to be inserted just once.
https://cimg2.ibsrv.net/gimg/rennlis...d190ef6cb4.jpg

That rear suspension design is virtually identical to my 911. I've swapped and indexed torsion bars so many times, ugh. I use a protractor phone app on the spring plates. Looks like camber and toe is adjusted in the same way as the 911, which is a lot of fun.

What events do you plan on hitting?

You are right, almost identical to the 911. Minor detail changes only.
I found out why I couldn't adjust the right side rear ride height previously. Someone red-loctited the adjustment bolts on that side!

I'm registered for Dixie, Charlotte and Grenada. Would have gone to Blytheville, but... Plan on doing Bristol.

Will I see you at any of those?

I plan on doing Bristol in the GS car. Jeez, you're cutting it close on Dixie, get that thing back together!

After corrosion-frozen bolts, bolts that were red loctited by some fool perhaps 20 years ago, bolts that snap in half and leave a section in the hole, bolts that have to be cut in half at each end and can only be cut by the best reciprocating saw blade money can buy, being sent wrong parts (conveniently) by vendors who then don't have the right parts in stock, nothing else can possibly occur to slow me down, right?

https://cimg4.ibsrv.net/gimg/rennlis...7bf408ebdb.jpg
Done. Procedure worked perfectly. Rear is now slightly lower than front, both sides equal, with the adjustment in the middle of the range. Now that rear is stiffer in roll I will try lowering the front back down to level and see if I get any rubbing. BTW, 3 degrees of camber all around. Death to Miatas!

Not bloody likely.

I recognize that there are several very fast drivers in ES, much faster than me. Locally I have a couple of Nationals mid-packers (but getting faster) in a 99 Sport (the Goofy Gomers) that I hope to be able to hang with and that I'm traveling with to Dixie and Charlotte. We will do a few days on St. Simons Island with the wives in between. I would have to beat them by a good margin to be near the top at Dixie. I get my only chance to test on Sunday at our first local event.

The M030 T-bars + a pair of JRZ single-adjustable rear shocks have really stiffened and settled down the rear end. It corners much flatter now and I don't even have the rear sway bar hooked up yet. Along with the 245 rear tires on widened (from 8" to 9") (from 7 to 8") rear wheels I'm half expecting massive understeer at the limit initially. It came down off the jack-stands with 3/8" rear toe-in, so I'll reduce that before Sunday.

The car has always felt down on power to me, smooth but kinda lazy getting to the redline with no real bite in the torque curve. I'm having the Cat back-pressure checked today and will replace it unless the exhaust guy swears it's perfect. From the extensive records I have it's original.

We may have discussed this, but are you using modern bumpstops, and do you think you're making it to them with how low the car is?

Interesting you should mention this. Yes, I'm using what RESuspension sells as RSW 3 series bump stops. I'm legal because the compressed length of the shock at the point where it contacts the bump stop and spacer arrangement I have is exactly the same as the Koni original. (I have a brand new Koni still in the box to compare too.) I just checked the rears at rest. The bump stops will turn freely, but will not move up hardly at all. (They sit on top of the shock body and are essentially free to move up and down on the shaft.) So, the slightest compression and I'm into 650lb/in territory, not counting the T-bars! No wonder this thing is so freakin' stiff in roll and rides so bad in the rear. I gotta raise the rear up.

Warned ya I could make this thing un-drivable!

Of course the whole point of thinking this car might be competitive is that the long stock bump stop + M030 sport suspension option may make it possible to be at Street Touring spring rates (using bump stops) and Street Touring amounts of negative camber. Careful what you wish for!

here's the front bump stops. 3 yellows + 4 spacers = same height as the stock Koni.
https://cimg0.ibsrv.net/gimg/rennlis...a3d00c6659.jpg


and here's the rears. Two purples + 2 spacers and the body hits the bump stops at the same length as the stock Koni.


https://cimg6.ibsrv.net/gimg/rennlis...1bff39cbd6.jpg

Each of these combinations produces about 650lb/in, but the motion ratio is probably not the same.

First event results: promising.

My co-driver today was a multi-time Nats champ who has owned 944s and a 924S back in the day. He said "I've never seen a 944 corner so flat or change direction so fast in a slalom."
Another National Champ came up to me after it was over (both myself and my co-driver had out-paxed him, which I never do) and said, "I think you've got something there, especially for a Nationals-type course that won't favor the Miata so much."

I designed today's course to be a Miata course...incredibly transitiony. I wanted to see if this 944 could hang with the Miata. It couldn't quite, but it was close. ES was won by a... Miata, of course, which was also top Pax. My co-driver was 2nd in ES and 3rd in Pax. (2nd in Pax was another multi-time Nat champ in an HS Fiesta ST.) I was 3rd in ES and 5th in Pax. Out of 99 entrants.

The bad part was how bouncy it was, especially the rear. Our lot has a lot of bumps. It is not at all smooth. At the lunch break I took the rear shocks out and removed one of the two bump stops to give a little more travel before contacting them. Still too bouncy, but better. We increased the rebound damping to the max on the front, even though the front was pretty good from the beginning. It got better. So much spring rate needs a lot of rebound to control it. The Koni struts were supposedly valved for spring rates of 900lb/in. It takes everything they've got to control what I've built. I was also running a lot of toe-out in the front and a Tarret adjustable front bar on full stiff. My co-driver wanted even more front-end response! I don't think there's anything else I can do for that. Only eliminating rubber bushings would help which wouldn't be legal in Street.

I have more rebound to crank in to the rear shocks. At the lunch break I ordered softer bump stops. I will go back to 2 in the rear but softer and with more rebound and that will be the setup for Dixie and probably Charlotte.

edit: and I will raise the rear up some more.

We both thought the car was a blast to drive. We both made it dance.

Death to Miatas.

Edit: Notes on spring rates when in the bump stops.

So, in sum total, the front spring is about 150lb/in and the front bump stops are about 850lb/in (after looking at the charts again) over the first 1/2" of compression, so the total is about 1000 lb/in. Jesus!

The rear is 175lb/in T-bar plus bumps stops of 880lb/in = 1055lb/in. Holy Jesus!

Tomorrow I plan to replace the purples in the rear. If I use the next lower durometer, the blacks, it will lower the bump stop spring rate to "only" 450 lb/in. Hmmm. Seems low. I really don't know how much rebound control I can get out of these JRZs. I could put in one purple and one black and get a number in between. Not sure yet what I'll do.

This is amazing. It's like all of my nerdy, likely poorly conceived AX dreams compressed into one glorious season. Send the 944 out with a bang!

That's the plan!

Cut front compression to minimum, raised the rear static height as much as the spring plate adjustment and a bottle jack could obtain, softened the rear bump stops by trading one purple for one black, leaving a black and purple paired on each side, found out I could increase the effective shaft length of the rear shocks by not threading the end fitting on farther than full thread engagement. This cuts the total rear spring rate to about 840lb/in, down from over 1,000. It certainly feels better behaved on the street, almost civilized, not that you want to go cross-country in it. Front and rear harshness feels about equal now.

Tuning for such high spring rates is a totally new thing for me. My co-driver on Sunday has so much experience he could quickly tell me what the car needed or at least which direction to go in to get better. Thank God the front struts had been revalved for 900lb/in springs or I'd be in trouble. (I didn't know that when I got them.)

I've got a binder of text, calculations and color pictures from the PET, 1989 Factbook, receipts, etc. to show my competitors to fend off any protest. It covers wheels, front springs, rear springs, front bump stops, rear bump stops, rear sway bar, and various bushings. I'll also have a stock Koni rear shock and a Koni front bump stop and a tape measure with me so people can verify my measurements if they want.

Of course if I'm not in the trophies no one will care, but I want to develop good will early so if the car is faster by Grenada, or maybe Bristol, or maybe...

Death To Miatas.

Well, Dixie was tough.

At the Evo school the car hobby-horsed badly when braking into a smooth corner on the high-grip asphalt. Added some front compression back in (about 1/3 from full soft) and that proved to have fixed it the next day.

Day 1 was dry. After the first run I was 8th of 20 in spite of a bunch of mistakes. Then DNF'ed two in a row with spins. One at the finish got an ovation from the on-lookers it was so well done.

Day 2 pouring rain (first run group only.) No rain tires and can't get the car soft enough/don't know how to drive this stiff car in the wet/standing water. Last run I actually drove pretty well. Way off the pace, however. Lesson learned: if you run BFGs must have Conti's on deck for rain or forget it. Glagola/Minehart switched to Contis between first and second runs. Glagola went from multiple spins in a single run to right to the top.

On St. Simon's now licking my wounds. Learned a lot and will try again in Charlotte.

Ugh bummer. Go get 'em in Charlotte.

knfeparty did well snagging a trophy in STX in his M5.

I saw that and giggled a little.

Charlotte had a good ES class with Peterson, Wayne, Minehart, Ellison, and Lindley. Initial conclusions: the 1989 944 just does not have enough wheel and tire for the weight.

The videos show that Day 1 the car was still a little bouncy and I was driving it like it was as wide as the Corvette. I got 2 reruns which helped a lot but was still 9th or 10th of 15.

For Day 2 I took 50% of the adjustment out of the Tarret front bar which was still on full stiff, left over from before the bump stops and found more optimum tire pressures for the surface. The car was easier to drive, if not quite as darty and had better grip. (I will try adding back 25%) No bouncing at all, the transition onto the bump stops is fine, the car is well-balanced and I finally drove close to the cones. I actually ran over the base of a cone once though I never knocked one out of the box.

I drove the final run yesterday about as good as I can drive. No mistakes, at the limit and my line was exactly as-planned. (As-planned may be wrong, however!) Still way off the pace of the top drivers/cars on a course that was good for the 944. I will drop 20 to 25lbs from the exhaust and get the anti-lock working but those are the only major things left, less head reconditioning.

Last year at Nats Day 1 on the corn side (dry) I was 1s off the pace of the top time in BS on a 60s course. If I give myself that 1s to the leader yesterday the car is about 1.5s off the pace.

As it is, 2.5s back from the lead on a 60s course would have put me out of the trophies in ES at Nats on the corn side last year. Not too far out, but out. That's the optimistic way of looking at it.

More realistically I was just a little faster than the Robinson brothers which would have put me right at the 50th percentile at Nats last year in ES.

Death To Miatas (and MR2s)

PS: Question- anybody think I could get a 245-40-17 RE71R on a 7" wide wheel and a 255-40 on an 8"? (Actually, the same sizes are available in Rival 1.5S)

Ed, I wouldn't read too much into results at zMax; that sealed asphalt gives a MASSIVE advantage to cars with low dynamic ground pressure. You're, what, about 3100lbs? And MR2 Spyder is about 2200? Same course anywhere else and the results could have been completely different. Same with balance; zMax appears to cause a large loss of traction to whichever end of your car is heavier: Front-engine cars tend to push terribly, and mid/rear-engine get super loose. The surface seems to favor Hoosiers and RivalS over RE-71R and RE-615k+, too.

I ran 255/35-18 RE-71R on an 18x8 wheel for several years. Extremely difficult to mount, but worked. If I recall, some of the S2000 guys are running 245/40-17 RE-71R on 17x7 wheels.

Thanks.

BTW, I'm thinking the car is ~2850lbs on low gas and no driver, but haven't weighed it yet.

Dennis Grant (Autocross To Win) says that an autocross car should be tuned for 2.5Hz in the rear and 2.2Hz in the front.

I found some authoritative (precisely measured) motion ratios for a lowered 944 race car and calculated what I think I've got when on the bump stops.

Rear: 2.5Hz (dumb luck)
Front: 3.5Hz (!!!!!)

Bump stops on the way that will bring the front down to 2.2Hz.

P.S. The wife objected to the idea of another set of wheels and tires.

Death To Miatas (and MR2s)

I don't know exactly about the bump stops, but I'd also bet they leave linear range with very little travel, similar to reaching coil bind on a traditional spring. I think there's a real chance your wheel rate is spiking to near infinite in some situations, maybe a lot of situations.

I guess if you're real bored you could switch to bump springs, which would probably stay pretty linear in rate up to ~80% of travel, but even a 2" bump spring only has maybe 1" of actual travel until coil bind, rate dependent.

I'm rating the bump stops after 1/2" of travel, so if a pair develop 200lbs of force at 1/2" total compression I call it 400lb/in. For 2 and 3 donut stacks they are all pretty linear up to about 3/4" of compression, which I figure is enough, but they're not bad even after that.

For instance, the green line on the attached chart is the curve for the 3 blacks (50A durometer) I'll be installing on the front struts.

As for bump springs I'm not clear on how to implement them legally. Glue (tack weld?) a spring together with two retainers and let them slide on the shaft? I don't know how they're usually done.
https://cimg7.ibsrv.net/gimg/rennlis...d22d871ac.jpeg

Good news and bad.

I took the car to a friend's house today for engine health checks. Compression was good at 200, 200, 205 & 205.
Leak down was ok also at 6%,4%, 6% & 9% (#2).

As I'm putting the spark plugs back in my friend pulls out a bore-scope. We look at cylinder one. (In this engine, like the 3.0 liter S2, cylinders 1 and 2 are siamesed together as are 3 and 4.) The piston looks good. Carbon in the middle but not around the edges. (I've done 2 Seafoam treatments.) The wall looks good with maybe a barely visible scatch or two. Then I see something strange: it looks like a drop of coolant running down the wall. Hmmm. My friend says he thinks it's oil. But, that's doesn't really make much sense to me and looks too thin to be oil.

I start the car and back out of his garage. He motions to me. There's a large puddle of coolant on the floor. More coolant has been trapped on top of the bottom panel and comes out when I back up more. It looks to have originated from the overflow tank vent line. (There's not a drop on my garage floor.) At our first event here in Huntsville some coolant came out in grid. At the time I figured it was just hot overflow from too much in the overflow tank, though I had filled it just to the mark.

Gotta be coolant pushed out by the 80psi leak-down pressure, right? Through the (failed) head-gasket?

Update on engine: bore scope shows all 4 cylinders have coolant intrusion to some extent. The good news is no white smoke, no overheating, no visible water in oil, engine runs fine, was unable to force coolant out with cylinder pressure or even hear any gurgling or see any bubbles. Still planning on a new head gasket sooner rather than later.

Update on setup: I changed the front bumpstops to get as close as possible to 2.2Hz with 1 yellow and 2 blacks on each strut. Ran local event today: increase in grip was evident. Front end moves and rolls some. I added a little more front compression and rebound at the lunch break. I won ES by a large margin and paxed 4th overall of 107. I expect to add a little more front bar for grippier surfaces.

On to Grenada Pro-Solo this coming weekend.

The Grenada Pro-Solo was disappointing, but instructive. Saturday was a flood and I didn't have Contis. I must have been the slowest car in the entire event. Sunday I had 4 dry runs before rain impaired the last 2 of 6. I matched my local guys, the Goofy Gomers (both have PHDs, btw) on the left side, but screwed up the right 3 times. Even on the left I was depressingly far away from the top, about 1.5s from first and 1s out of the trophies on a 32s course.

I've bit the bullet. I have a set of Cup 1's in 17 by 7 and 8 coming. Will go to RE71R 245 and 255, assuming my tire guy can get them on. 7.3% wider tire patch, in theory. And it will get me to 56mph in 2nd instead of 51. Most of the fast ES cars are running 225s on their 6" wheels. With my 225 on 7 and 245 on 8 I've had only slightly more rubber for a lot more weight.

I don't want to make it sound like it's all the car, it's not. I think the car has about as much grip as the Gomers now, but probably less than the 225 folks. Last run on the left side I finally woke up a bit and drove it better, unfortunately it was raining again by then. This momentum maintenance thing is tough. Very hard to know the correct trade-off between carrying speed and adding distance. Still learning that. Basically, I use the brakes too much leading to periods where the car is not at the limit and has lost too much speed. I could see that others were adding only a slight amount of distance in order to produce a much higher average speed.

I ran into Sam Strano at Charlotte. He knows me from my Corvette-driving days. He asked, "What are you driving now, something weird I saw?" I told him I went to a 944 in ES to learn momentum maintenance. He said, "Well, you picked the right car for that!"

245/40 on 7 and 255/40 on 8, RE71R Bridgestones. Badly scuffed-up 17" Cup 1's I got cheap that I'll plasti-dip glossy white.
Tire guy said only slightly more difficult to mount than normal. Didn't charge me any extra.

It will be a while before I get to test them out. Missing the next local due to a trip next week.


https://cimg4.ibsrv.net/gimg/rennlis...ef76beae45.jpg

https://cimg3.ibsrv.net/gimg/rennlis...ffefdd3263.jpg
I'm no longer a member of the Tiny Rivals club.

These 17s seem huge. 9bs heavier per corner, wheel + tire. Gearing change is very evident, as is the faster response from the Stones. The "true 8" wheel" variation in offset gives it a little more rear track as well as compared to the widened 7" phone-dials where all the new width went to the inside. Edge of rear tire is now +10mm closer to the fender on each side. (Still legal with the 7mm spacer.)

https://cimg4.ibsrv.net/gimg/rennlis...7efd2c1a27.jpg
Removed the cylinder head and took it to Memphis Motorwerks for reconditioning. The pic is of piston #1 mostly cleaned of carbon. I should have the head back next week. Little to no corrosion, not warped, so just a few thousandths skim of the surface is all that's needed. All valves cleaned up good. There was some pitting on the back sides of the exhaust valves. New guides, new springs.

The head gasket was in really bad shape, allowing coolant intrusion into the cylinders, as seen a few weeks ago by bore-scope. Some think you should wait until you see white smoke, poor leak-down or compression or other obvious signs. I don't think so. If you are losing any water in a 944 find out why. 944 fiber head gaskets should not go much beyond 100K miles in my book.

So I'll have a freshened engine for the Bristol events.

FYI, I've successfully had my local Firestone mount 275/35/18 on 18x8 for several years. It is a little sloppy but is the absolute maximum tire avail for 8".
My buddy has used this method to win a variety of NTs and Pro Solos with my underdog cars (rx8, 996, and most recently 997 GT3) over the years

Good info, but I can't go to 18" and there's nothing wider in 17".

The optional 8"-wide rear wheel on these cars was 16" diameter, so the legal diameter range is 15" to 17"

But, if I decide to go to Nats with my Corvette in BS once again and get beat by the M2's I could do 275/315-18 Rivals on the 8.5 and 9.5 wheels. It's a possibility depending on what happens in the 944 at Bristol in a few weeks. It's not clear yet that this new wheel/tire combo is actually faster than the narrower tires on 15" wheels.

https://cimg3.ibsrv.net/gimg/rennlis...cf33aa96a6.jpg
Got the head back from Memphis Motorwerks. Near mirror finish where it was surfaced, except for
dark spots that are areas of corrosion pitting. I plan to assemble with Permatex 51813 (Anaerobic gap filler) in these areas.

Got the engine reassembled and running fine. Had a test & tune on Sunday where I compared 245-17 on 7" (fronts) & 255-17 on 8" (rears) RE71Rs vs. 245-15 on 7" and 245-15 on 8" Rival-S.

Rivals faster by 1s on a 40s course even though had to shift up to 3rd and back down once. The 245 on the front gave awesome grip.

17" wheels/tires are almost exactly 2" diameter larger (gives me 56mph in 2nd but hurts acceleration and raises CG by 1") and 9lbs per corner heavier.

Lightness and lower CG win. Back into the Tiny Rivals club.

Edit: I also got runs in an SSR C7GS on Hoosiers (awesome), a turbo-Miata in SSM (don't like turbo lag), a CS S2000 (rolls too much without a front bar but they are great anyway) and a full-race old-school Camaro with who knows how much horsepower and a pneumatic paddle-shifter for the auto-trans and I couldn't hardly reach the pedals or the steering wheel with the fixed seat set for the very large driver and the harness wouldn't adjust enough to hold me in...(Yup. I spun it.)

Edit 2: Two of my ES competitors who drive a '99 Miata Sport each took a run in the Porsche. "You should never be able to beat me in my Miata with this car." was one conclusion. "That you have, in fact, beaten me tells me you're driving the crap out of this thing."

Goal achieved: Trophied in 3rd place in ES at the Bristol Match Tour last week.

https://cimg1.ibsrv.net/gimg/rennlis...ba34a0d13a.jpg

Awesome! Great seeing you, unfortunately I didn't get to see you run, other than hearing you come through the finish as I was pulling up to the start line.

Man, you were killing it in GS. 1st place in the Match Tour and a trophy in the Champ Tour. Congrats.

My lack of downshifting skill & experience killed my chances in the Champ Tour. I think I've got it down now, so hopefully can do better at Peru.

Peru was tough. I think we (co-driver and I) were losing a lot in the longish transition section, plus we had to do a lot of shifting while the Miatas did not.

Day 2 there was a 5-cone slalom and then a set of offsets after coming out of a slow 180 turn-around. The winning Miata hit rev limit right at the 4th cone in the slalom, which is 58mph. We were only at 50mph at that point, just shifting into 3rd. I suspect that section alone was the difference between my co-driver (2018 CS Pro-Solo Finale winner) in 5th and 2nd. I was way down in 8th. I went to school on the data from my co-driver and think I learned something useful.

On to Nationals. The car really pulls high lateral-G's now, so hoping for lots of big sweepers. It also sounds good with a lightweight cat-back system using a Burns Stainless. Lost 17lbs. Goal is to finish in the top 50%.

edit: in a big push to get ABS working. Modulator was totally corroded. New (used) one going in now, but I had to cut one of the brake lines to get the old one out. Learning all about DIN bubble flares.

edit: ABS is fixed!

https://cimg1.ibsrv.net/gimg/rennlis...72470275a3.jpg
Time to bring this thread to a close.

I took the car to Nats and it drove great. Power was good, even better with Miller's Nano racing oil in it. Handling was best it's ever been, thanks to some tweaks suggested by my co-driver. Pulled peaks of 1.25g's all over the place. OH, and the car sounds great with the Burns Stainless 2-stage muffler. A 3" cat-back system saved 17lbs.

One of the front bump stops was found to be ripped out on the morning of Day 2 as I was stiffening the front sway bar, but trapped within the spring coils. This seems to have hurt max lateral G on that side just a little. My co-driver was within striking distance of the trophies after Day 1 on the corn side. I sucked.

Day 2 on the plane side I think we both drove quite well (except for my co-driver coning his fast run) but all the shifting killed our chances. 4 upshifts to 3rd and 4 downshifts. I didn't miss a shift in 3 runs, but I think it was just too much on a speed-maintenance course.

I'll be removing the extra bump stops and doing a few other things to prepare it for sale.

Big congrats to PedalFaster and Burglar on their trophies!

This was an EPIC odyssey to follow, thanks so much for sharing the journey with us.

So, uh, what's next?

I vote Porsche 968 for C Street!

I'm set to co-drive a friend's BSP MazdaSpeed Miata next year. The owner just done blowed up the motor, however, so I'm taking the downtime to figure out what his shock valving out to be based on the Dennis Grant calculator. His Penskes apparently leaked enough fluid that the dyno showed they weren't doing much of anything.

BTW, I have curves for three different sets of Penskes that were speced for 3 different Street-class Corvettes by a well-known supplier. The shock valving is different for each (one GS and two C6Z06's) but there is one common denominator: the shock valving is insane in rebound, as in 200% or more critically damped. (One of them may have enough adjustment that set soft they will be okay.) I had co-driven the GS before and kept losing the rear when accelerating during an increasing radius sweeper. On concrete. Now I know why.

I did the calcs for my B-Street Corvette and have just enough adjustment to reset the Ohlins to get close for 90% critical damping in both compression and rebound with the soft stock springs. Driving it around it seems very different, but in a good way. I have an event to test at this weekend.

One last thing:

https://cimg2.ibsrv.net/gimg/rennlis...8daab7cb50.jpg

As I was readjusting the front sway bar softer for street duty I found this. These two pieces form a triangulated mount that comes with the Tarett 944 adjustable sway bar. I remember hearing a loud metallic ping during one of my runs on day 1 at Nats. Now I know what it was.

So, the FSB was unable to develop much if any force in either direction after being completely disconnected from the body on one side.

I'm getting kind of wound up about maybe doing a 986 Boxster S in CS next year. (I have a co-drive in a BSP Miata (that never happened this year) so this would be a backup.)
I faced-off the ND2 and the 03/04 Boxster S in the latest version of my autocross spreadsheet. Results below. I was kinda shocked. Assumes 8"/10" wheels for the Boxster as run by the winner of the last trophy in CS at 2018 Nats. Probably 255/35-18 on the front and 285/30-18 rear. Front could also be a 255/40-17 for maybe less weight.
Of course, intangibles like the lack of front camber are not included. But, even if that knocks 1 or 2 points off the Boxster S, it's still in the competitive range.
The wide range of tire sizes now available, especially the RT660, makes this appealing, along with the ability to stiffen it with bump stops, as I did the 944 and as is being done by all the fast ND2s, as well. But the stock Porsche bump stops are even longer than the Mazda.
Opinions?

https://cimg5.ibsrv.net/gimg/rennlis...931a7b46c.jpeg

About the ND2 vs. Boxster S: I did a thrust chart for the two which makes the ND2 look a lot better than just using peak torque as I usually do, especially with the new 215/35-17 Falken tire which is only 23.8" in diameter. I'm assuming the ND2s will switch to that tire from the 225 they've been running which is 25.0" in diameter. As a result, I factored the Boxster S thrust rating down to where it was a little below the ND2. This is a course-dependency where if the Mazda doesn't have to use 3rd it's in the gravy. If it does, the advantage goes to the Porsche. The resulting ratings have the two cars dead even and are shown below.

https://cimg3.ibsrv.net/gimg/rennlis...6dcaa6a17.jpeg

https://cimg0.ibsrv.net/gimg/rennlis...bd5425fac.jpeg


If the ND2 has the 225/45-17 on it then the Boxster S looks better. I'd probably call it a wash.
https://cimg9.ibsrv.net/gimg/rennlis...306bbba54.jpeg

Damn, that's a nice thrust curve for the ND2! I'm curious now- how does that compare to 987 thrust? My data's been showing ND2 out-accelerating my 987.2S and I'm curious.

The rear-weight bias of the Boxster will help put some of that power down on corner exit; not sure if that's enough to overcome the other inherent ND2 advantages. I think a 986S would be a fun build, though, especially now that Konis are available.

I'll try to find a good dyno sheet (dynojet) on the 987.2S. I think the weight on the rear of the Boxster is just enough to overcome the lack of an LSD, so a wash in my estimation.

What's the story on these new Konis? Single adjustable? Revalvable? I haven't liked Konis much in the past for autocross. I'd be fine with non-adjustable, as long as I can get them revalved to my specs.

Edit; looks like the 8740 model is another twin-tube, low-pressure type like they've been doing for 30(?) years. Nothing really wrong with it, cheap, but not a particularly large piston (meaning lower sensitivity and lower grip) and, AFAIK, not capable of high damping at low shaft speeds without getting too much at higher speeds. They claim it is revalvable, however. I guess I'd have to buy them, have them dynoed locally, then see what Koni could give me that would be closer to what I'd want and send them back out.

S: Tell me your rear tire and weight.

I've been running 275/35-18 on my 987.2S. Ryan was running 285/30-18 on his 987.1S when he won BS in 2017. My rear weight (987.2S Boxster S PDK) is 1706 without driver, 1834 w/ me.

Great, except I meant the total weight!

I found a good dyno graph for a 987.2 Cayman S. It'll have to do for now.

Oh, hah. Weight is 3064lbs in race prep at bingo fuel without driver, 55.67% rear bias. My car is likely pretty typical of AS prep. Driver weight is biased left and slightly biased front.

Do you have a source for this being legal? I’m 100% sure (having run one nationally for a season) that in the 2000s the largest legal wheel size was 7.5” F / 9” R.

I know that Exclusive options have since been made legal, so an order guide listing 8”/10” wheels as an Exclusive option would suggest that they’re legal now even if they weren’t back in the day.

You probably are getting beat, at least up to 45 mph. When the ND2s go to the new 215 tire with 23.8" diameter it will be even worse.
(It's almost like Mazda knew what they were doing re: autocross.)


https://cimg6.ibsrv.net/gimg/rennlis...c5ea0b155.jpeg

I don't, but the guy at 2018 Nats thought he did.


UPDATE: I was wrong!!!! The wheels were 8.5" and 10". These are the pictures I took that day at the dealership. I also took a picture of the order sheet, but I can't find it now. These are Carrera-look wheels but not the same as the ones you actually got with the Carrera, which I think were wider in the rear, probably 11's.

UPDATE and correction: these wheels were on a 2006 Cayman S, not a 986.




https://cimg5.ibsrv.net/gimg/rennlis...a0b73e1619.jpg

https://cimg6.ibsrv.net/gimg/rennlis...dbda677ab1.jpg

The owner's manual for 2004 listed 8x18+50 & 10x18+47 wheels as an option for 986 and 986S. Whether that alone would hold up to a protest, I'm not sure, but it's in the manual. 7x18+55 / 8.5x18+48 was also an option. But if he was running 8.5" front as it looks like, I don't think that would hold up to a protest.

The only Boxster in CS at 2018 Nats didn't finish very well (43/52), so I doubt anyone cared enough to throw paper.

I'm talking about this guy below who trophied in 14th and (I think it is him) said he was on 8s & 10s based on option data he got from a dealer, not on what the manual says. He was 18th of 53 in a BS 987.1 Cayman S in 2019. He was also 3rd in DS one year, only about 2 10ths out of 1st over 2 days, so no slouch of a driver.


https://cimg2.ibsrv.net/gimg/rennlis...0099ffa43.jpeg

UPDATE: Sorry guys, my apologies. PedalFaster is correct. I went back and found my original post from 2013 when I took these pictures. The car was a 2006 Cayman S, not a 986 S.

So, maybe Paul Dodd really does have proof of the 8s & 10s.

I was skeptical, but I know Paul! He's a standup guy -- he definitely wouldn't do anything he thought was questionable rules-wise.

It's pretty late, but I'll message him in the morning to ask about this, and stalk his Facebook timeline in the meanwhile to see if he ever posted about it. :)

That would be great. To me, the difference between 7.5/9 and 8/10 is an uphill slog vs. an almost even matchup.

I chatted with Paul today. Summarized:

The 8"/10" wheels are listed as IXRC ("Sport-Techno Rad 18" / 18" SportTechno wheel") in the parts catalog downloadable here: https://www.porsche.com/all/media/pd...SA_KATALOG.pdf.

The 8"/10" combination is apparently also documented in the owner's manual, but Paul points out that only means it was a factory-approved wheel combination, and doesn't prove that it was an orderable configuration.

When he bought the car he was under the impression that the legality of the IXRC wheels had been established like the legality of the XRR wheels has been for the 987, but as he's dug into the topic more, he's become concerned that the documentation may not be strong enough. He (and I) thinks you could have ordered a car like this through the Exclusive program, but can't prove it.

Thanks very much.

I think the only chance of proving legality is if we find a 2004 Order Guide which shows it. I found a 2003 Order Guide which does NOT show it. I think I'll go down to my dealership. Worth a try. If it's in the 2004 order guide it would only be legal for a 2004, I think.

Sidenote: You can still buy those exact wheels from Suncoast Porsche where they are listed as fitment specifically for the 986 Boxster and NOT the 987. Why produce a specific set of wheels for the Boxster if it was never an option to buy? Interesting, but doesn't prove anything.

As an aside, if you do end up buying a 986, it should probably get a new thread. :)

Also, I forgot to mention that Paul's opinion is that the car's uncompetitive even with the wider wheels. He pointed out that 2018 was the year of massive rain, and he had real rain tires (PS4S) in a mid-engined car.

Good info.

There you go crushing dreams again. I still want to do it.

I've always thought that weight has more to do with performance in the wet than anything else, though I don't know why. The ND1, being ~500lbs lighter, probably can't be beat in serious rain. I certainly felt that way with the 944. I had a good tire width to weight ratio which worked pretty well in the dry but in the wet I got hammered by the Miatas, and I consider myself reasonably fast in the wet. (Part of the problem may have been being unable to get the shocks soft enough, however, plus the harsh bumpstops.)

That said, I'm not discounting his opinion that the Boxster S is uncompetitive even with 8s & 10s.

Dixie Winter this past weekend was another case of taking a knife to a gun fight in CS (S2000 vs ND2). I enjoyed the challenge but being the fastest S2000 and 3rd place overall only goes so far. I discount day 1 because of unfamiliarity with the car, plus trying left foot braking and plus a course that favored the ND2 (the S2000s spent too much time on the limiter at 60mph while the ND2s forged ahead.) Day 2 the course was fairer, I used right foot braking and drove about as good as I'm capable of but still way off Rick Cone's pace. I'm not sure I want to assume the plucky underdog role again.

Man, the S2000 is a really fun autocross car! Especially when it's on properly-valved Penske shocks.