Rear diff bushings

[jaymzz]

My rear diff is hopping around pretty bad since I put a new clutch in. Buschur offers solid or urathane bushings. I do a lot of drag racing and autocross. Would the solid bushings be better? Not to concerned about road noise. Thanks in advance.

[Warrtalon]

How do you know the rear diff is hopping around? A clutch wouldn't cause that unless you mean you're getting wheel hop? If so, then that requires a change in driving style. Bushings are not a solution for what you've explained so far.

[jaymzz]

I figured it was the rear diff. It does it when I am in stop and go traffic pretty bad also. When we had it up on a hoist, the rear diff moved around a lot. If not the rear diff, then what could be jerking around so badly in the rear end? Doesn't matter if I launch it, or take off slowly it hops around badly.

[Warrtalon]

I don't know - it depends on what you mean when you say "it hops around badly." I've never heard of such a thing, so I figured it was just a case of not knowing how to explain the sensation. Are you saying that the car shudders when taking off from a stop, or are you saying that your rear diff physically bounces up and down under the car when you start driving? I would be extremely concerned if that were the case. If it's just the shuddering that I mentioned above, then that's what you get with a stiff clutch - usually a pucked clutch - and requires taking off from a higher rpm.

[jaymzz]

I will try taking off from a higher rpm. The car does shake around pretty bad when I take off. It doesn't do it all of the time, but does it enough to where I am not comfertable with it. The last time I drag raced it, it had some severe wheel hop or the rear diff was hopping. I tried different rpm's when launching it. Tried 5000, 5500, and 6000, but seemed to not stop. Never had this problem with the stock clutch.
Thanks for your help Warrtalon.

[Warrtalon]

Yeah, the stock clutch is very weak, so it shouldn't happen except when launching on a really grippy service occasionally.

What clutch did you put in? With my Exedy 4-puck, it would shudder badly going into 1st or reverse from a stop, because that's just how it works. It required high rpms to just get moving normally in 1st, but when launching, it was in its element. Now, my Exedy Twin Carbon is wonderful and engages like the stock clutch while providing 3-4x the power holding ability.

[jaymzz]

Running a 6 puck ACT. You just described what it is doing. Tried starting off with a little more rpm's today and it helped a lot. Also tried a few launches at work and seems to have really bad rear wheel hop. What would be a way to stop this? The only upgrade done to the suspension so far is coilovers.

[Warrtalon]

Just going to have to figure out the right combination of RPM, clutch release, and tire pressure.

The 6-puck is not for the faint of heart...

[jaymzz]

Cool, thanks for all of your help.