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Post by Rigrock on Jul 24, 2005 23:40:47 GMT -5
Any of you guys have trouble running the et street radial and getting into wheel hop? If I launch soft its ok, but transbraking or spraying off the line and it wheel hops all through 1st gear. This is on a leaf spring Nova running 10's on the 275 tire. Tried air pressure all over the map, but didn't help much. Possibly shocks are the next trial but wanted some opinions or someone who already went through this. What shocks have you guys had luck with?
Thanks
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Post by Mike Stark on Jul 25, 2005 11:13:31 GMT -5
Good shocks go a long way. Check you pinion angle. Sounds like it's off a bit. Should be about 4 degrees down. What bars are on the car? Calverts? Slappers?
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Post by Rigrock on Jul 25, 2005 17:19:01 GMT -5
Pinion angle is 4 1/2. I was unning slappers with j-bolts, and just went to the caltrac last time out. I tried both the upper and lower holes, both were the same. My rear shocks are the CE 3 ways on 50/50. I was looking to go to something like the Rancho adjustables, but I think they only adjust the extension, not the compression.
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Post by Rick Robinson on Jul 26, 2005 8:32:24 GMT -5
I'll give it a shot. Real wheel hop is caused by spring wrap up which should be eliminated by the use of Cal-Tracs. Extension adjustable shocks are what you need. Double adjustables are nice but in most cases, not necessary. More than likely what's going on is tire paddling from not enough air pressure. Have someone take a look at the tire marks after you launch. If the tires are too low in pressure..they will see a distinct pattern..that shows skipping vs a nice smooth pattern. If the rearend is really hopping..then there must be a bind somewhere..or like Mike suggested the pinion angle must be severely off. I'm assuming your pinion angle was measured negative..if it's a positive 4 degrees then you already know the problem. Good luck...call me if I can help. Rick www.motorsportsengineering.net317 627-RACE |
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Post by Rigrock on Jul 26, 2005 9:35:24 GMT -5
Thanks for the responses. Yes, it is 4 1/2 down. The air pressure I tried was from 18 down to 12, everything in between. I also thought the caltrac would eliminate the wheel hop the way it hits the top of the spring. I'm wondering if its just bouncing off the track due to the stiff sidewall, the Hoosier DOT is soft and absorbs the shock of the tire. It actually skips on the track, and the other guys I race with can hear it in the pits when I leave. The harder I leave, the worse it is. I think I've lost a few fillings out of my teeth ;D trying to fix it. I was actually thinking that increasing the compression of the shock would help it from bouncing the tire back into the wheelwell. I see QA1 shocks adjust both compression and rebound at the same time, but I think the Strange only adjust rebound? I'm not sure about the rancho, but I heard they don't last long. I'd like to stay with a single adjustable shock $.
Thanks again
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Post by Mike Stark on Jul 26, 2005 21:06:02 GMT -5
Top secret Caltrac settings:
Bottom hole. Set with 0 preload on drivers side. Put about 1 flat of preload on the passenger side. should run fine there. Make sure the car is at race weight and you are in the seat. Have a buddy make the adjustments.
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Post by Rigrock on Jul 28, 2005 6:06:24 GMT -5
Thats real close to how I have them set up. One thing I noticed watching the video is the car initially seems to bite as the front end lifts, but just as the front end reaches full travel, thats when the hop begins. Maybe this is where the rear shock rebound comes into play?
Thanks
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Post by Mike Stark on Jul 28, 2005 22:16:05 GMT -5
Slow the front end rise down. When the front control arms bottom out it shocks the chassis and unloads the rear. This is your biggest issue right now. Try a 70/30 setting and see what happens.
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