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951 suspension & To lower, or not to lower...

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Old 12-13-2007, 05:10 PM
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cb951
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Default 951 suspension & To lower, or not to lower...

Looking ahead to suspension upgrades.

'86 951 -- daily driver with occasional DE. I'd like something a bit stiffer than stock, but not too jarring on the street.

Based on RL research, the possibilities are:
1. Koni yellows with GC (Paragon) coilover front conversion (maybe 300# springs), torsion bars (maybe 28mm). Good for the street, I think I might outgrow it for the track.
2. Bilstein Escort coilovers (probably 300# fronts and rear rate to balance using re-indexed stock torsion bars). Great for track use, but might I regret it for street use?
3. KW Variant3 coilovers (double adjustable damping; not sure about available springs/rates). Just discovered these, and need lots more info.

----------------------------------------------------
EDIT (added 2/5/08):
Now leaning toward the KW V3 kit, but am also interested in the Cross kit (available currently at a "special blow out" price which puts it around the same price or cheaper than the KW kit, AND includes adjustable camber plates).
-----------------------------------------------------

Sway bars:
A. M030 30mm FR and 19mm RR.
B. Weltmeister.
C. Tarett (probably overkill for my purpose, and $$$$).

Then there's the issue of whether or not to lower the car (1"). I know about the benefits to handling (and looks).
Q: Is it worth it to lower the car if it's mostly street driven? I'm concerned with potholes, speedbumps, driveway inclines, etc., not to mention the added difficulty in jacking the car for service. Any regrets from those who have done it?

If the car is lowered, then I need to address control arms. I understand that, for DE, most PCA regions require some sort of aftermarket control arms if the car is lowered. I'm aware of the reasons for this.

The leading contenders for arms:
a. Charlie arms (Wrightwood Racing) -- very nice, difficult to get, and VEEERY $$$$. There's a thread about a possible group buy for $1895 per set. That's a 20% increase over the already prohibitive price of $1500. (Stable Energies still shows them at $1595.)
b. Racer's Edge -- seems to be the new leader due to Charlie arms availability. I believe $1595 from Paragon.
c. Kokeln -- I believe $1758 from Stable Energies.
d. Lindsey Racing -- chrome moly round tubing (look similar to Kokeln) for $1595, but includes the rear castor block.
e. Marcus Blazack -- square steel tubing, less refined looking, a bit cheaper.
f. Various claims of modified stock arms, which I don't trust.

The cost of control arms adds a lot to a full suspension package (plus machining the spindle hole from 17mm to 19mm) and, if I didn't already have a torn bj boot, I wouldn't even consider them at the start. But, if I need to replace the arms anyway (and I don't want to go with any of the rebuilts), then the cost of aftermarket arms becomes the difference between that of stock and aftermarket. (The "in for a penny, in for a pound" attitude has resulted in various mods I just finished, and can't afford.)


So, to sum up --
I need to do suspension (not immediately, but before I DE again). Should I lower the car? Which strut/shock/spring/torsion bar set-up? Rates? Which sway bars? Which control arms?

I wish I could drive or take a ride in cars with various set-ups to get a "feel" for them. Anyone in the NJ area willing to get together?

Thanks in advance for your advice.

Last edited by cb951; 02-05-2008 at 11:20 PM.
Old 12-13-2007, 06:22 PM
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Spidey944
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I would start with sways, struts and shocks w/camber plates. Then make your disicion on the control arms. You may find that driving with upgraded shocks/bars etc it a lot of fun. Albeit for a while. You almost have to save something for upgrading later IMHO. I love having something to look forward to later, and since I don't feel like pulling the motor and going through it just yet, the suspension has been my focus as of late.

I am VERY happy with my manual steering rack, 26.8 sways and bilstein HD on the rear for now. I am contemplating the Bilstein Firehawk setup myself, but for some reason, no one ever talks about them as being good or bad. My other option is to source some early strut housings and modify them to accept the Bilstein inserts and to fit the 86 spindles as I have heard this is a good way to go also.

I see you have already done the engine side of the performance of the car. I have always been a big believer in suspension to handle the extra power b4 engine mods, but it sounds like you have a great platform to build on already.

You are now faced with the ultimate desicion, the same one I toss around in my head all day long, "What is best for me?" If there were more people with mod'd suspension setups in my area, I'd LOVE to drive them, but I am stuck waiting till maybe next years GTG in Ohio to drive/ride in some other cars for comparos. As you are in NJ, and there are a few more ppl in your area, I'd try to arrange some drives/rides if you can, and get some feedback in person. This is a big choice, I just can't bring myself to make it yet.
Old 12-13-2007, 06:25 PM
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jpk
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On the early car, I piecemealed the suspension upgrades a bit at a time; first 250# lowering springs in front, then koni yellows all around, then finally 28mm Tbars. This was done over the course of 2 years. When it was all done, I was pretty happy with the car; it was a bit firm on the street, yet not overly harsh, and it was pretty tight and well ballanced on the track.

When I got the 968, I thought about doing something simmilar, but when I added up the cost of replacing the springs, struts and t-bars, it wasn't much of a stretch to go with the KW coilovers. I went with the "standard" 968 set up in the Var3; they're like 340f/285r spring rates. The rears work along with the factory t-bars, but you need to index them back (I went 2 splines on the outside, and it was more than enough to get the full range of rear height adjustment)

I also installed the racer's edge camber plates at the same time. I just recently had to replace the KW plastic spring hats with billet aluminum racers edge because the bearings in the camber plates were chewing up the spring hats.

I'm still using the factory sway bars right now. New bushings are on thier way, but it don't think I'm going the change the bars themselves yet.

Right now, I'm a bit over 1" lower than stock, and there are no clearance or binding issues with the control arms. I'll keep an eye on the balljoints, but I don't think it's a problem with only 1" drop. If and when I do have to replace them, I'll rebuild the stock arms.

I'm really happy with this setup.The car is nicely streetable, yet fells pretty well composed on the track. It still has a much heavier feel than the early car did though.
Old 12-13-2007, 07:13 PM
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Darwantae951

 
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There are places that sell kits to rebuild your ball joints with longer ones to correct the geometry on lowered cars. You shouldn't "have" to get all new control arms.

Check www.rennbay.com and click the ball joint rebuild kits link in the upper left.

-Darwin
Old 01-10-2008, 04:15 PM
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cb951
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Any other opinions?

Anyone in the northern NJ area willing to take me for a test drive?

Thanks!
Old 01-10-2008, 04:49 PM
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Waterguy
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My car sees similar service as yours, perhaps more track oriented. I have a similar set up to your option #1: Paragon/Koni coil-over fronts, 300 lb coils, Ground Control camber plates, Welt 28 mm sway bar, Koni shocks, matched rear spring rates (combination of heavier torsion bars and 968 M030 coil-overs in my case), Welt 22 mm rear sway bar. I am very happy with this set-up for DE and autocross purposes. I find that the car is at my limit for ride comfort in street car. If I were to go any stiffer, it would quickly become a dedicated track car. Surprisingly, the stiffer shocks seem to affect the ride comfort more than the spring rates, though.

You might consider the 968 M030 sway bars; they are lighter than the Welts and not as stiff. I do like the added adjustability of the Welts, and do use it to balance my car as I am becoming more comfortable with trail braking, car balance and throttle oversteer.

Regarding ride height, I would not lower the car any further than M030 ride height. Further lowering screws up the suspension geometry, lowering the roll centre, which induces extra body lean. My car looks like the rally/off road version compared to some lowered 951s at the track, but has less body roll using equivalent spring rates. YMMV. I believe it is more important to level the car front/rear and to get a good corner balance and alignment.

You might also skip the adjustable camber plates and go with the fixed monoball plates. You can't adjust the camber without screwing up your toe-in anyway (ask me how I know!)

Plan on replacing your spring plate bushings when you do the torsion bars, as the original rubber bushings will be hammered out of round by now. Elephant Racing makes a nice set; bit of a bugger to install but worth it.

Since I don't recommend lowering your car, I don't see the need for aftermarket control arms for simple DE uses. Racing would be different.
Old 01-10-2008, 04:59 PM
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Techno Duck
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Chris, do you know a guy named Vaino from the NNJR PCA? He has a 968 with the KW Variant 3's. From what ive read he liked them alot. I can try and get his contact info if you dont know him.

I have no direct experience running the KW V3, but from what i have read about them on other applications (Subaru and Evo's) they area fantastic setup and well liked as being streetable and VERY track capable. If it means anything, im pretty sure the M3 CSL that just recently set the street legal car lap record on the Nurbugring was using KW V3's.
Old 01-10-2008, 05:37 PM
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cb951
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Waterguy,
Thanks for the great, detailed, on-target info. 300 lb fronts (with matching rears) being at your limit for street comfort sounds like what I would expect, though I'm trying to arrange some test drives/rides to "see for myself".

What is the M030 ride height (lowered by how much vs. a stock '86 951 standard suspension)? I'd consider lowering my car about 1". I appreciate your recommendation to not lower, but I also want to consider the possibility of lowering it in the future. If I do, then I'd have to consider upgrading the control arms and, since I now have a torn bj boot, I'll probably have to go for some arms anyway. I don't want to get stock arms and replace them with upgraded arms later.

I'm pretty sure I won't need adj camber plates at all (at least for a VERY long time). I hadn't considered rear spring plate bushings, but you're probably right, even if I end up with a coilover kit and just re-index the stock TBs.
-------------------------

Jon,
I don't personally know Vaino, but I've read some of his posts on the NNJR forums. He seemed happy with the KWs a couple years ago. I would like to get in touch with him to possibly get a test drive/ride. I guess I could pm him through the NNJR forum, but I'm not sure how long it might be before he checks there. (The NNJR forums don't see a lot of activity.) If you have his direct contact info (and you don't think he'd mind if you gave it out), then I'd appreciate that. You can pm me.

The KWs seem to be gaining popularity and I'm interested, but I'd like to find out what springs they use (not just rates, but mfr and compatibles), for the ability to change spring rates later.
-----------------------------------

Thanks for the input.
Old 01-10-2008, 08:01 PM
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jpk
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KW makes thier own springs I believe. They are just a hair smaller ID than a standard 2.5" spring (maybee 1-2 mm), so when I added the racers edge aluminum hats (upper spring perch) I had to press it into the helper spring. It shouldn't be a problem to use a 2.5 inch spring instead of thiers though.
The stock Var3 setup for the 968 has 340# front and 285# rear, but they will send you any spring rate you want. Somewhere on thier website, I found thier full line catalog which lists part numbers for everything. I'm pretty happy with the stock rates though.
One thing I really like about the coilovers is that I can adjust the ride height at will. I started with the car lowered nearly 2 inches, but I'm back up to within pretty much an inch of stock now; I'm guessing it's pretty close to the M030 settings. Swapping out the springs would be pretty simple as well - it shouldn't even affect the allignment settings if you're careful.
Come on over to Michigan and you can try mine out
Old 01-10-2008, 08:06 PM
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Techno Duck
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Chris, try to PM him on the NNJR forum as he will probably get a email notification. Otherwise im not really sure how to get a hold of him. Thought i had his email but cant find it.

BTW, it really depends how much you want to spend on your setup. Im my opinion the KW is the way to go if your willing to drop some coin on it (i think going rate is $2800 right now). The Koni coil over setup will run you less than $1200. The Bilstien setup is nice, but i cant help but think it hasnt been improved on since the late 80's when it was used. But then again, it is a RACE CAR setup..and you know how they say if it aint broke, dont fix it.

As for control arm options, being you have an early offset car i would go with the Markus Blazak control arms. Ive heard nothing but good about them..and if my car was early offset, i would have used those also.

For camber plate options, if you dont need the adjustability the KLA monoballs are a very nice option and also the pair is about half the price of ONE factory strut mount.

For sway bars, i think Z-Man (also a NNJR guy) was using a 30mm 968 front and a adjustable Weltmeister rear which he always talked highly of. I felt like i didnt need that much adjustability so went with a 26.8mm front and 19mm adjustable rear on my old 944. This was to try and dial some of the understeer out of the car due to my 200lb front springs and stock rear torsion bars. Other than cost, the big downside of the Weltmeister bars is weight.
Old 01-10-2008, 08:06 PM
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J Silverman
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Originally Posted by Waterguy
Regarding ride height, I would not lower the car any further than M030 ride height. Further lowering screws up the suspension geometry, lowering the roll centre, which induces extra body lean. My car looks like the rally/off road version compared to some lowered 951s at the track, but has less body roll using equivalent spring rates. YMMV. I believe it is more important to level the car front/rear and to get a good corner balance and alignment.
.
Right on the money. Basically you want to lower the car until the control arms are paralell with the ground. Anything past that point and you are too low and roll will increase. Ive got my car slammed right now, but thats because the sprigns are too short. Ive got a pair of longer springs that should bring the car back to a decent ride height.
Old 01-10-2008, 08:24 PM
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Techno Duck
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I used to run around my car slammed also. It really looked awesome, but i had to avoid going to places due to steep driveways / entrances .



I was also using the longer balljoint pins from Rennbay. Surprisingly i never had issues with bump steer.

My 951 is at factory ride height and did not come with any adjustable suspension, just Koni's and stock springs. I actually love the way it rides right now, firm but dosent have the same 'edge' my old 944 had on the bumps. I do want to lower it a tad, but nothing crazy like how i used to run my 944. Its nice not having to drive up on 2x4's to jack my car up, or sticking two 2x4 pieces as stand offs when putting it on a lift....etc. Just pain in the butt stuff like that. Also i want to put a AIR front splitter eventually..and i hear even at stock rideheight those can be difficult to keep in one piece!
Old 01-10-2008, 09:23 PM
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KLR
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Surprisingly, the stiffer shocks seem to affect the ride comfort more than the spring rates, though.
I think this is very true. My car has stock springs and t-bars, but received Koni yellows all around when the original shocks/struts wore out. The ride quality and impact harshness in my car is very stiff/rough, and certainly doesn't seem particularly worse than cars with 300-400 pound springs and matching t-bars that I've been in. The rebound on the shocks is adjustable, but I've never messed with it because the car doesn't show any evidence of the rebound rate being too high (i.e., jacking down, etc.) and I don't see why the rebound rate would affect the ride quality.
Old 01-10-2008, 10:00 PM
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cb951
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Originally Posted by jpk
...Come on over to Michigan and you can try mine out
John,
Thanks for the KW info. I had checked their site, but didn't see any specifics about other springs. I'll have to check again...Michigan is a little bit far, even in a Porsche, but thanks!



Originally Posted by Techno Duck
Chris, try to PM him...Thought i had his email but cant find it.

...Im my opinion the KW is the way to go if your willing to drop some coin on it (i think going rate is $2800 right now).

For sway bars, i think Z-Man (also a NNJR guy) was using a 30mm 968 front and a adjustable Weltmeister rear which he always talked highly of.
Jon,
I'll pm Vaino. Thanks for checking.

I've seen the KWs at $2360, and two weeks ago, one place had a sale at 20 percent off the 2007 price (about $1960 or so), but only through the end of '07. They might still do that price, but I'm not ready now anyway.

I've been in touch with Z-Man. Trying to arrange a test drive/ride with him. He's running the Koni/Paragon co kit at 400 lb. May be too stiff for me, but there's only one way to find out.
--------------------------------

Thanks to everyone for the info. Please keep it coming.
Old 01-20-2008, 04:29 PM
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cb951
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I sent Vaino a pm on NNJR on 1/11 and then emailed him on 1/18, but no reply. Anyone know how to get in touch with him?


Anyone else in northern NJ with KW suspension on a 951, 968, or 944 series?


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