Best shock/spring combination for street/track

[Anders Dahlquist]

Just received my 2002GTS after selling my 96GTS. I do some track time and the stock system is too soft and too much rebounce.
Urethane everything is ordered but what do you guys think is the best spring rates and shocks brand/type that will be great on the track and not kill my back on the road. I have price quotes from 1'600$ to 5'000$ and don't want to do it twice. Thank you.
Anders/Geneva/Switzerland

 

[CitySnake]

Anders:

Try posting your question in the main RT/GTS section. You'll likely get more responses there.

 

[Anders Dahlquist]

Thank you for the advice.
The counselling(!), obviously not from here, is as following for you other beginners:
Springs hard versus soft: prevent the car to rock in longitudinal direction during hard acc/braking and sideways in turns.
Shock absorbers: do the same(!) but when the movement is a short burst.
Conclusion if you do a long braking or long turn, the springs are prioritary otherwise shocks are.
What does the swaybar do? Prevents the car leaning in turns as the springs do. Conclusion: If you put big swaybars you can have softer springs(also softer on your back). Weight transfer during braking/accelerating will still be a concern.
My first step is: Sway bars.
Any opinions??

 

[99 Sidewinder]

Just like yourself, I wanted better handling but I did not want to get beat up on the street.
I upgraded my 99 RT/10 with the Koni ACR Shocks and love them for aggressive street driving and AutoCross. The factory spring rates in 99 were 200 lb/inch front and 400 lb/inch rear. The Koni ACR's are 400 lb/inch front and 750 lb/inch rear. The Koni ACR's have plenty of adjustment for bump and rebound dampening as well as ride height adjustment. You may be able to test ride a VCA member's 99 or early 2000 ACR. (They are also 8lbs lighter per shock.)

I am very happy with them. Also... Not one single rattle.

 

[jrkermode]

Anders,

You were somewhat misled on the influence of shock absorbers. The latest, fully adjustable shocks are tunable for low and high speed response in both compression and rebound. Consequently, shocks can tune your car's performance even in relatively long transitions. You may wish to search for a very similar thread posted within the last 2 weeks.

The short answer is, start with the most adjustable and rebuildable shocks you can afford. If you still can't tune the handling to your liking, then start experimenting with springs. If you start the other way around, springs first, you may end up choosing spring rates too much for your shocks to control.

The stock GEN II suspension geometery has a nearly perfect amount of anti-dive and anti-squat. Consequently, the springs that work best to prevent dive and squat typically come real close to being what you want for roll control. Here's a hint: virtually nobody offers replacement swaybars, virtually everybody offers shocks and springs.

If you're running street tires, you may also wish to rethink the urethane suspension bushings. They will indeed enhance feedback from the suspension (what some people call harshness). However, their primary benefit is more precise control of wheel travel. This is important for race tires which are relatively sensitive to scrub, camber, castor, etc.... Street tires, though, are more forgiving of these small movements, leaving you with just the harshness which you mentioned you didn't want.

 

[RockyTop]

I have double adjustable JRZs (Moton shocks are virtually the same as the guy there came from JRZ). The spring rates I have were intended as a base to start from and are 600 F and 800R. The Viper Days racers are running like 1200 R and who knows up front (probably like 700-1,000).

My bump is set at 7 clicks front (1 being full soft) and 10 rear. My rebound is set at 10 front and rear (1 being full soft). I used to have them at 4 bump F&R and 6 Rebound F&R. Changed them at VIR and picked up 1+ seconds.

 

[Anders Dahlquist]

To jrkermode,
Good advice about the urethane.
I have had another source saying the same.
A friend has a street legal historic race Camaro and since installing urethane doesn't use it on the street anymore.
So anybody wants to buy a polyurethane kit?
I have installed a 2 way spring/ shock set up frome Snake Oyl/Collectors Choice.Good price, nice service and in stock. It's like another car. Fantastic. Scared the hell out of me on a mountain road: nothing beats physics: you can't drive way to fast in corner and get away with it.
Took it also on the race track: great and I love the ABS on the wet.(Blew away a Corvette and two Porsches and some unfortunate Vipers). Okay some guys were faster but they cheated.
A very happy ABS owner,
Anders