Ever since I have the Viper, I keep working on it to improve handling and stability. The weakness of that car, IMO.

Already made pretty much all the usual modifications: good tires (Kuhmo ACR's), solid sway bars w/TKO links, TKO bushings, coilovers with stiffer springs, Wavetrac diff... And I'm on my 3rd alignement setting.

I'm satisfied with the front-end stability. Made few errors first (too much camber/not enough caster, too much toe-in, tire pressure too low for street, etc...) but now it feels very good.

On the other hand, I'm still stucked with the rear-end problem: under hard acceleration, the car struggle to keep a straight line. Especially felt on a roll, not a standing start.


And I'm not sure what causes it, what is the culprit for that behavior.
Don't get me wrong, it's not that bad, it's a RWD without traction control (gen3) and a lot of torque, I don't expect miracle. But I'd sure like to fix that issue the best I could.
Can't imagine it could be a tire or diff problem. Maybe the BC coilovers or springs? Doubt it, but possible. So what's left?, alignement?


The alignements I tried so far:

Camber F -2.6 :: R -1.7 :: Caster F 6.6 :: Toe-in Total :: F 0,20deg :: R 0,34deg
(1st - basically ACR specs)

Camber F -2.1 :: R -0.8 :: Caster 7.3 :: Toe-in Total :: F 0,38deg :: R 0,44deg
(2nd - less camber to get more caster, and a lot of toe-in)

Camber F -1.6 :: R -0.6 :: Caster 7.8 :: Toe-in Total :: F 0,08deg :: R 0,38deg
(3rd - even less camber for even more caster, lot less toe-in front)


The 3rd one feels the best for street, especially the front-end. I'm basically maxed out for the caster while having decent camber. Having a lot of toe-in on the front was an error but I wanted to try anyway. Just a tiny bit of front toe-in seems perfect.

Now, back on the rear-end issue, my educated-guess would be to try more camber and/or more rear toe-in to keep that snake straight and stable under hard acceleration.

Any comments or tips?