Wheel hop

[2wheelsrbest]

Howdy folks. Gave forum a good looking over, just registered. My issue...

02 P5, new to me w/78k on completely stock car. Kumho Ecsta Supra tires with only a few miles on them.

Car launches fine in straight line, with nice, even wheelspin if you want it. Turn to the right and do same (free right turn) and there is hellacious wheel hop. I need to find a solution before things start to break apart.

Tires are in good shape and aired 32-34psi. Motor mounts are not torn/ripped, but are stock. Suspension feels tight--no slop/rattle/knock/clunking. Shocks "seem" tight, too, there is no porpoising after bumps and damping seems to work great.

The only thing I've done to test any particular theory, is to jam holes of motor mounts full of wooden dowel to stiffen them up (Don't get on me for hillbilly ways--for test purposes only!). This DID help things out a bit, minimizing wheel hop under right turn, but it is still bad enough that further solution must be sought.

Anyone have suggestions?

If urethane motor mounts are the answer, do ALL of your P5s have bad wheel hop without them?

 

[JCell]

i had really bad wheel hop b4 my motor mounts, but it's all good now

if u r trying to stay in warranty, then just get the front motor mount and change it b4 u go to the dealer, it is a 15 minues install, and u won't regret it

 

[2wheelsrbest]

2-22-05 follow up

So I left my car with a reputable friend who runs a local shop. He had his crew drive and look my car over.

They thought that everything (suspension and motor mounts) looked ok. They balanced front tires which were 1oz off each (prob not big contributing factor).

He had two things to suggest. First was that he did not like the Kumho Ecsta Supra tires. He said they had a stiffer carcass across the tread area, which has less compliance and therefore was more likely to slip (due to inability to conform to road surface) and then grab (soft rubber compound), creating this violent oscillation. Second, he found that higher tire pressures helped quite a bit.

Tire pressure after I had dealer check before purchase was approx 25psi (knuckleheads...). I aired tires to 33-34, higher than door sticker, but lower than 44 psi max rating on sidewall. He raised them to 38psi.*

Car does not ride any harsher with higher tire pressure. Wheel hop is greatly minimized with the current setup. So much so that I will likely call it good, aside from filling/replacing front and rear motor mounts for fun. Inside wheel slips and grabs a bit when spinning wheels in a corner, but the manner in which it does so is SO much less violent than before--I'd call it normal.

*Tire guy said that max rating on sidewall is max cold inflation pressure, not max attainable pressure. I understand to check tire pressure when cold, but had always thought that the 44max was pressure a heated tire should never exceed. He indicated that short sidewalls and reduced air volume sport tires liked to be run at this much higher pressure and I'd have to say the performance thus far has proven that.

Hopefully this can help someone in the future.