3 times ago at the track, I launched, had awful wheel hop, and broke my transfer case front diff. I put a new transfer case in, and replaced all 4 stock motor mounts with the Avid aluminum mounts to stop the wheel hop. I went back to the track and had no wheel hop at all, just ludicrous amounts of wheel spin when my tires were set to 36 psi of tire pressure.

I went back this past Friday, and aired the tires down to 25 psi all around. On my launches, I felt a pretty bad "wheel hop" type feeling, so I let out immediately, since I did not want to repeat my broken transfer case like weeks before. All night when I was having people watch my car, they said it was spinning the tires, and I kept telling them that it felt like it was coming from the rear of the car.

Later that night I got home and watched the video from my launch where I let out due to the hop, and I am indeed spinning the front tires, and it looks like there is no hop at all in the front (23 seconds in to the video):

http://www.youtube.com/watch?v=iwEX1...e=channel_page


So..... could this be my rear suspension hopping, or possible the rear diff bushings giving, and the diff itself hops up and down? My car weighs 2875 so it is extremely light, I make 356 awhp on a mustang dyno, and launch with an exedy triple plate clutch at 9 psi of boost and 6,000 rpm. What do you think of this?

I don't mind spending money on the buschur rear diff mounts and such, but I don't want to waste my money there if it is not the problem.

-mark

 

Bump, any drag racers on this site? lol

 

well, first off, i am not wiz but in the drag section i was reading (depending on the tire) to run like 18-20 psi of tire pressure, are you running street tires or slicks? also try posting this in the Drag section.

 

Anyone else get this?

 

When we show the first sign of hop, I drop the front tire pressure by 1 psi and begin making adjustments to each tire (front the same, rears the same, but 1 psi different). It's always helped us eliminate the problem. I didn't look at the tires, but which brand and type?

 

I have BFGoodrich KDW's. At 35+ psi, I was roasting the tires bad like this:

http://www.youtube.com/watch?v=PbZPOyvFOw0

At 25psi, I still spin the front, but get hop in the rear like in the video in the first post. I just don't know what a common spot for hop is, but I am almost certain it is coming from the rear.

 

I have been reading and watching videos of launches and it seems that springs definetly help the car launch better. I am looking in to picking up some myself to help with my launch.

 

Springs on front and rear are the ticket. A bouncing car is not ideal.

 

My next purchase will be the meagan coilovers then! Let's just hope it's not the diff, i'll be sad spending a grand on coilovers, when it's not that, lol.

 

The rear diff doesn't cause wheel hop.
Wheel hop CAN cause broken diffs however.

 

Oh, I am well aware! I am just saying, I am not 100% certain if it was wheel hop or not, I just felt a violent "banging" in the rear of the car. I assume it is wheel hop, but if diff banging around was a common evo problem, I would like to fix that fast.

I assume those bushings are fine, and it's the suspension, I am just looking for advice.

I may do the suspension, AND the diff stuff, just to save weight. It would be RIDICULOUS to have my car under 2800 lbs