Running Time Attack today with my 92 Player's Z28 (stock except for Koni yellows, Hawk HP+, and Kumho XS) I'm getting rear wheelhop when braking uphill and the rear end gets light at the top. It shuddered like that a couple of times and then I had a dead speedo and a VSS code. Limped it around the track like that for testing, tried a few different braking zones and now I get the shudder every time, no matter where on that hill. No wheelhop anywhere else on the track, ever. With the CE light on the car likes to stall. I'll probably start by replacing the VSS at the trans (T5.)

Thoughts?

 

Yeah that'll fix the VSS code and the speedo, maybe; won't have any connection with the wheel hop though.

Sounds like a combination of nose dive and rear lift.

What springs are in it?

 

Stock 1LE

 

So, you're trying to say you're attempting to competitively race 20-yr-old wear-out parts?

I'd suggest some new springs that aren't all used up. Start there, work outward. Shocks probably next. Unless those are still OE as well... in which case, they need to go at the same time.

 

Pretty much

Konis are new, springs unknown. It does pitch a bit under braking.

Found trans mount to be toast. Should I replace the TA bushing at the same time? Any reason NOT to use polyurethane?

 

Trans mount being toast will cause probs.
Some claim a trans vibration with a poly trans mount. I run both a trans mount and a tq arm poly. Both are good parts even if you pickup a lil vibration..

 

On my Koni yellows, I turn the rears to full stiff. Still get axle hop sometimes on bumpy sections, but it's a lot better than it was before. I did this on my old LS1 Camaro (the LS1 cars being notorious for axle hop) and I rarely had issues.

Pat