autobonrun

That is an excellent parts diagram. I like the way it lets you pick an choose.

I looked at some of my old receipts and they total around $2500 in suspension mods on my 79SC for the parts I upgraded. I didn't do all the upgrades shown in the diagram.

I only ended up 1) replacing my stock shocks with 4 Bilstein Sports 2) Replaced the stock torsion bars with 21mm front/27mm rear hollow Weltmeisters 3) Installed Neatrix bushings for the stock units that were flattened due to age and 4) lowered the car to around 24"/24.5" and got an alignment. I also changed the tires to Bridgestones but I didn't include that in the pricing.

These changes alone improved my track time on a 2 mile circuit by about 8 seconds. The car is much more planted and predictable. My SC came with Woodhead shocks as the OEM and the Bilsteins really brought the car back to life.

Here's a good technical article that I used in selecting how much additional stiffness I wanted via the upgraded torsion bars. It also shows what the stock torsion bar diameters are for SC's and Carrera's.

http://www.pelicanparts.com/techarti...rsion_bars.htm

I did all the work myself except the lowering and alignment. I must say that replacing the rear spring plate bushing is the most difficult project I've done to date on my SC. You literally have to cut or burn the bushing off. I ended up using a torch and it comes off in a hundred pieces although I've heard some that have been able to get it off in one piece. In hindsight, that's one job I'd pay to have done.

Bottom line is if you still have stock suspension parts on a SC or Carrera, these changes will really improve the handling of your car. IMO.

One last thought, I spread out the upgrades over a 2 year period to spread the cost and so I could evaluate each change rather than just throwing parts at it. First I did my shocks, then drove the car at a track event to see the effect and determine if I needed to change my torsion bar ratios. It meant I needed two alignments but I had a better idea of what ratios to use.

r911

The downside of ITBs is that you cannot resonance tune the intake plenum like Porsche does.

onboost

Shannon, if your looking for a cost effective suspension upgrade.. DARISC's combo on is pretty much spot on..

You may be able to find the 26mm t-bars relatively cheap as they were factory 930 bar size.. On a cab, I like them with a 21 mm front bar, and the Bilstein HD in front along with strut bar... just in an attempt to cut down on cowl shake. I'd go through and replace the rubber bushings as needed also... with new rubber ones, again.. just because its an open car. Just a thought!

Do it soon.. can't let those miata things get that close!

P-

DARISC

Good point - I'd neglected the fact that it is a cab.

911vet

Thanks for the advice. I've been trying to figure out what size t-bars to use. What are the stock sizes? Just wondering something here... if 26mm is larger than stock, won't that stiffen up the rear and actually induce more oversteer?

Is there a reason to go with Bilstein HD rather than Sport? And are you suggesting Sports in the rear and HD in the front?

I will definitely be adding a front strut bar. And I figured new bushings and ball joints were probably needed.

I'm talking to the guys at the body shop about welding together a bar to stiffen the chasis in the passenger area of the cockpit. My roll bar makes a significant improvement in chasis stiffness and handling. But I've been advised against using it with stock seats (due to possible spinal injury in a rear-end collision). But I was thinking (dangerous) that maybe my buddies at the shop could weld some kind of bar that runs across the floor of the passenger compartment.... what do you think? Anyone ever done such a thing?

I would rather spend money on suspension upgrades than the $2000 it would cost to get Recaro seats, harnesses, seat braces, etc just to use the roll bar. Then again, that would allow me to use it at DE school.

What to do, what to do.

dsmith

correct, but onboost is recommending that with the 21mm front bar, also bigger than stock. There may be a better site, but the link below has a good synopsis of changes/effects. In general, stiffening one end relative to the other from a current setup will reduce traction on that end. Finding the balance that YOU like, based on your driving style and competence is the journey.

http://www.rallylights.com/other/stuning.htm

911vet

Thanks for the link. I went through this with my bimmer a few years ago. But I've never dealt with torsion bars and I have to admit they are still abit of mystery to me.

dsmith

Just think of your TBs as the springs.

911vet

Yeah, that's what I'm trying to do. I was used to the languare of springs (spring rate, 400lb vs 500lb springs, etc). But when someone says a 26mm t-bar I have no basis of comparison.

I will turn to you guys for advice on good set ups. Thanks.

murfysflaw

Hilarious!

justinsrx7

I couldn't agree more. My 1993 RX-7 TT compared to my 911 is light, easy to drive, blazingly fast, and handles like a dream. That being said, I love driving my 911. I owned a BMW and it was by far the worst car I have ever owned. Spent a ton of time in the shop and didn't even have all wheel drive. For winter driving, I am now an Audi fan and have been driving one since 2000. Amazing in the snow.

By the way, the Audi never even enters into conversation when I am talking about my sports cars.

schnele

I have had an E30 M3 my first new car, an E24 M6 built by Don Fields of Autosport Performance in NJ, an 850 for a brief stint (way too mature for me) nothing feels like my 930 not even the two 993tt I have owned excites me like this car. FYI my 930 is not stock and while I have not driven it since the EFI conversion it did make 394 at the wheels before the EFI now 558 at the wheels at 1bar with nearly matching torque numbers.

racer

If it was a brand new M5.. were talking V-10 with about 500hp. 8,000rpm redline. He was just toying with you. Likely still keeping it under the "break-in" rpm guideline too... Heavy, yes. but massive brakes and motor. Certainly makes it feel lighter than it is.

Was this what you saw? : http://www.bmwusa.com/vehicles/m/m5sedan/default

DARISC

Yeah, but....one is dangerously sensory deprived if one cannot feel the profound difference between hurling 2700 lbs as opposed to 4500 lbs into a turn, no matter how adroitly the bigbig car deals with overcoming the law of physics that doesn't want that to happen .

Slinging 2700 lbs around at speed is fun. Slinging 4500 lbs around at speed is, to me, kinda scary and unnatural.

Molly

These should summarize what you where up against..

http://www.youtube.com/watch?v=dy5Twk4Wd7o

http://www.youtube.com/watch?v=_zYWOqm_Zkc