Gen1 handling upgrades? (Aldan? KW?)

[obaa996]

So as the driving season is pretty much at an end, I'm planning out my upgrades for the winter. Already on the list are some better brakes and new wheels, but I'm also wondering what I can do in the handling dept.
I currently have some Eibachs on mine, with the shocks set halfway on the front, and 3/4 on the back (back being softer than the front). Alignment was redone to '95 specs after the lowering. I've been autocrossing with the suspension setup like this, along with some Pilot Sports set at ~36psi.
It seems to me that the front pushes a lot. When going around a steady state corner, I can get the front howling, but any surface irregularity will cause the rear end to step out in a big way. The car also seems to crash pretty hard over bumps/potholes/etc.
Would reseting the shocks help with this (stiffer? looser?)? They've got ~40k on them, so perhaps they are due for a rebuild? There doesn't seem to be many other suspension options for these cars, and I don't know what they will buy me. I've seen Aldan and KW options available, but there's a huge spread in cost (4x), and having the Koni's rebuilt will like be in the range of the Aldans. Just wondering what sort of suspension tuning others have done, and what the bang-for-buck results were. So going to a genII is out...

 

[KepRght]

a set of lighter SSR wheels with 335/30's on the front AND rear will be a huge improvement in that front push you describe. you could go 315 in the front if you fear the 335. Tires; go with mich pilot sport CUPS or hoosier A6(autocross) R6(RoadRace), swap this set in for auto cross will be a huge improvement.

40k-60k on a set of shocks is about max before replacement or rebuild, i would think the stock oil filled adjustable koni's are better then the gas filled aldan's, but that's just my thoughts on shock construction. you might consider a set of new stockers. or (low mileage) stockers from someone who upgraded. if you can go all the way 4500$ penske's are amazing.

consider sway bar bushings in urethane.

also consider upgrading control arm bushings to Delrin ((but)) that will make the ride even more stiff over *** holes. your comment on the *** holes and bumps is true; stiff shocks and bushings are great for good handling, and bad for ride quality over bumps. its a toss up & OEM mfgrs usually go for a soft ride to make people comfortable. that jaring ride over bumps is what gives you good high speed handling characteristics.

gl with the project!

 

[Tom F&L GoR]

Perhaps the rears need to be softer to not come around. I have fronts full stiff (5 out of 5 half turns) and rears softer (1.5 of 5 half turns.)

The clutch type differential uses a friction modifier to provide smooth engage and disengagement. I found over bumps when one wheel gets less traction, the two rear wheels tend to come to the same speed and stay together rather than split/share the load transfer. Acting like a solid rear axle will produce oversteer. The FM wears out, so adding another bottle from Dodge may help. And after 40K, maybe it's due.

I modified the stock shocks to be able to put other springs on; 550 front and 800 rear. It rolls over less and I think you'll run lower pressures and still keep tread on the ground.

This might help:
http://solotime.com/browseproducts/Carroll-Smith-Engineer-in-your-Pocket.html

You can purchase aftermarket sway bar bushings that will make transitions noticeable quicker and you won't have to anticipate and play catch-up. That may help you feel what else you want to mod...

 

[Early93Viper]

I have Kumhos V700s on mine along with stock shocks full stiff up front 2/5 on the rear. The car handles great on a road course. A lot more Predictable than stock with mild oversteer. Although it still will snap around on you if your not careful. But Kumhos do a lot. Defiantly you’re best handling bang for your buck.

 

[RedEnuf93]

Tom, you would not happen to sell those schocks for us GEN 1 drivers?

I am also in need of upgrade, the right front shock went south (leaking) so I am looking possibly Aldans. Or some modified stuff like Tom's!

I intend to tear down the suspension too, since the car is 13 years old (and I have nothing to do when it snows in PA) .

Any bushing info would be GREATLY appreciated!!!

 

[FrankBarba]

You can add sway bars, Gen 2 Upper A Arms, Different Shocks that have perches on them so you can change your spring rates. To add additional stiffness during cornering email me & i will explain the best that i can what i did to accomplish this....Less roll....PS...if anyone is looking for different spring rates let me know. i have some sets for sale. $ 50.00 per spring.

 

[obaa996]

Wow; lots of good info. Thanks!
Is there a site that might have wheel weights? I've got a set of '01 wheels; they seem to weigh a lot. I'm pretty much narrowed my wheel choices to CCW classics or BBS LM/ACR. As for tires, I've got a small stockpile of Pilot Sports I need to go through first (or sell).
315's up front? That must be on 12" rims; certainly not the stock 10" size? They will fit without rubbing? That should definitely help with the understeer, although I have a hard time visualize such a huge front contact patch! I can try softening up the rear some more. Is there a limit to how big the difference should be between the front and rear settings?
Penske/Ohlins/Moton would be nice, but realistically out of my budget. I didn't know they even made a fitment for the gen1's. It seems rebuilding the stock koni's are probably the best bet. At least one of the Koni authorized places was implying that they could convert them to double adjustable shocks (not that I would know how to adjust them properly) and possibly add adjustable spring perches. They could revalve the shocks to put the current adjustments back into to the middle of the range, and check to make sure the shocks and springs dyno evenly.
My local shop was recommending this route over the Aldans (they aren't familiar with the Aldans, no experience with them, etc. so didn't want to recommend them). They thought the cost of the mods would be offset by the cost of having to create custom shims (in lieu of adjustable spring perches) for setting corner weights. I'm thinking this is a necessary step for my car, because I seem to be consistently locking up the right front tire. They also suggested that they could set a more reasonable ride height for street use along with alignment settings for better tire wear, and then do a measured drop (calculated by counting threads on the spring perches) for track use, which would also result in increased camber for better handling. It sounds like a good idea, though I don't know what amount of drop would equal what degree of camber.
What spring rates are the Eibachs? I'll have to call them, and see they compare to what you guys are running
I'm open to the idea of poly bushings. The stock shock bushings are definitely hammered and I'll bet the control arm bushings are in similar shape. The only thing is the noise; the ones on my truck squeak and groan. I can deal with in a truck, but not a Viper... Is there a way to mount them such that they don't do this?
Are there adjustable swaybar droplinks? One thing that was mentioned during my last alignment was that the bars were preloading the suspension somewhat. Adjustable links should fix this, but I've never seen them for sale?
The rear diff fluid was changed at ~35k, and I put in one bottle of the Mopar additive. Would it get consumed in ~6k miles?
Frank, I'll be sending you some mail....

Thanks!

 

[Tom F&L GoR]

Lauri, I have another set of shocks (from eBay) I had always planned on modding for a friend with another '94. The problem with selling them is that I need some shocks to work on first, I can foresee owners not wanting to buy them (because they think theirs are "newer"), and others won't want to return their old ones. I can also see folks not wanting to send them to me first and letting their car sit for a while.

On the plus side, it's kind of like Dave's brakes (actually Dave only sells brackets): modding the shocks is unique, but not high-cost, and everything else is store-bought parts. If you have any ideas about this, let me know.

WARNING: If you are going to press the bushings out of the shocks, plan on supporting the body very well. They are extremely tight fits and you can bend the body and/or rod.

The service manual shows how much camber you get for an amount of wheel travel, for both front and rear.

For autocross I've run shocks full stiff in front and full soft in the rear. It's OK for a short course since you can yank on the wheel all you want and not get initial oversteer.

That all changes with rear brakes that do something. If the rears do some work, corner entry is more "classic" in that you have to brake in a straight line, braking on entry leads to drifting or oversteer (followed by throttle steering) and being able to rotate the car (less long-turn push.)

You can get rid of the sway bar preload by putting the car on a flat surface, loosening the body mounts, and adding shims under the one that is not flush on the frame.

No, 6K miles should be fine with diff fluid.

 

[obaa996]

I'll check the service manual tonight to see what the camber changes are. I think they mentioned a difference of ~1 degree camber difference between street and track settings, so maybe that falls within the range.
Thanks for hints on sway bar preload. Aren't the body mounts rubber? Will the shimming be counteracted by the body mount compressing?
Does the additional braking from the rear cause a loss of traction, leading to the rear stepping out?
I did some checks about getting the shocks rebuilt. The place was quoting ~$237 per shock for a rebuild/revalve, and $225 labor to modify all 4 for using sleeves/adjustable perches. The sleeves and perches ran $63/set, and take 2.5" i.d. springs (the Eibachs should be 64mm, so they should work).
If I wanted externally adjustable shocks, they would charge $387 each. Finally, they sell new custom valved single adjustable Konis for $450, and double adjustable for $550.

 

[Tom F&L GoR]

The sway bar uses a metal bracket around a rubber sleeve over the bar itself. If you loosen both brackets, car is level and flat, one bracket will be flush with the frame and the other bracket will not be. Put shims between frame and bracket in the gap and tighten. The bar should then not have any preload.

The rear braking will cause some rear wheel drag and depending on where you are in the friction circle, may induce oversteer. While this sounds bad, at least in my case, it was that I got used to having no brakes in the rear and it seemed like now I had to pay attention. However, it is what the experts call trail braking and it becomes another tool you have to use. And you learn you should brake in a straight line. Once you reacquaint yourself with decent brakes, you can still fine tune it with the removal (or not) of the proportioning valve spring or cup seal. The alternative is external plowing into corners...

Will that place accept putting on sleeves and adjustable perch work without having to do the rebuild? $225 to convert OEM Viper shocks is not a bad labor charge. For an additional $63x4 for parts and ~$65x4 for springs you would have lots of adjustability.