Wheel hop under braking
10-16-2007, 02:42 AM
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Wheel hop under braking I was just at an auto-x this weekend after putting new rotors and pads on the car. It brakes so much better, that I am getting the rear to hop under very hard braking. What will help keep the rear planted so it doesn't happen? I am planing on new sway bars next spring, and may also get some shocks if i have the money. What else?
10-16-2007, 07:22 AM
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That can be a big problem with 98+ cars. Shocks can help. Upgrading the torque arm to a stronger, full-length, stock-like version can help a little. Stay away from most of the torque arms that are shorter than stock (anything that doesn't mount to the transmission). Lowering the rear tire pressure can help a little. Braking earlier and more smoothly can help a lot.
The Unbalanced Engineering Decoupled Torque Arm will eliminate most or all wheelhop, and help you hook up better at the launch. It is expensive and takes some work to install and tune (think of installing headers compared to installing a lid). It can also exaggerate clutch chatter with an aggressive clutch. I did have to do some retuning when I switched from a Spec2 to an original Textralia (not their new milder dual friction disc). I've got that working very well now, though. A 1000hp, radical cam, triple disc setup might be a b*tch to set up for good street manners, but that's probably true anyway, and it wouldn't be an issue while driving "in anger".
There's a lot of discussion on this topic at frrax.com. You may have to register to see most of it. Try searching on hop, UETA, and decoupled. If you're interested in the UETA, there's also a very long thread with "breakthrough" in the title that's worth reading all of. There's several generations of breakthrough documented with theory mixed in along the way, so be sure to read all of it. In a nutshell, the early adopters had to do some experimenting, but at this point I think we know what works and what doesn't.
A month or so ago, a C-Prepared driver came over and asked how I managed to set my car up to be so well behaved while launching and braking. Usually you have to trade one off against the other.
There is disagreement, of course. Strano is not a big fan of the UETA, so read all of his comments too. Shocks and tire pressure are still important. I wouldn't bother trying to change anything else until you take care of the shocks. And, no matter what you do to the car, braking too late going into a turn is slow. The UETA will let you brake somewhat later, but you still have to drive it.
The Unbalanced Engineering Decoupled Torque Arm will eliminate most or all wheelhop, and help you hook up better at the launch. It is expensive and takes some work to install and tune (think of installing headers compared to installing a lid). It can also exaggerate clutch chatter with an aggressive clutch. I did have to do some retuning when I switched from a Spec2 to an original Textralia (not their new milder dual friction disc). I've got that working very well now, though. A 1000hp, radical cam, triple disc setup might be a b*tch to set up for good street manners, but that's probably true anyway, and it wouldn't be an issue while driving "in anger".
There's a lot of discussion on this topic at frrax.com. You may have to register to see most of it. Try searching on hop, UETA, and decoupled. If you're interested in the UETA, there's also a very long thread with "breakthrough" in the title that's worth reading all of. There's several generations of breakthrough documented with theory mixed in along the way, so be sure to read all of it. In a nutshell, the early adopters had to do some experimenting, but at this point I think we know what works and what doesn't.
A month or so ago, a C-Prepared driver came over and asked how I managed to set my car up to be so well behaved while launching and braking. Usually you have to trade one off against the other.
There is disagreement, of course. Strano is not a big fan of the UETA, so read all of his comments too. Shocks and tire pressure are still important. I wouldn't bother trying to change anything else until you take care of the shocks. And, no matter what you do to the car, braking too late going into a turn is slow. The UETA will let you brake somewhat later, but you still have to drive it.
Last edited by sgarnett; 10-16-2007 at 07:37 AM.
10-17-2007, 03:08 AM
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Thanks for the advice. I will look into it.
It wasn't so much braking for the corners that I had a problem with. I am a very smooth driver. The finsish was set up where I was doing about 45-50mph and had a very short distance to brake after the finish. My last two runs I wheel-hoped after the finish. I just don't want to encounter the wheel-hop in an emergancey braking situation on the road (like for a deer on my way home at 2a.m.)! My car is my daily driver, even in the winter. I would love to, but I can't realistacly lower the car with my parents drive way and the back roads I take to work. I am already scraping the K-member on the ground in a couple of places. I would like to put the 35/22 sway bars on the car and get some good shocks. I have heard koni's are good. Any suggestions on shocks?
It wasn't so much braking for the corners that I had a problem with. I am a very smooth driver. The finsish was set up where I was doing about 45-50mph and had a very short distance to brake after the finish. My last two runs I wheel-hoped after the finish. I just don't want to encounter the wheel-hop in an emergancey braking situation on the road (like for a deer on my way home at 2a.m.)! My car is my daily driver, even in the winter. I would love to, but I can't realistacly lower the car with my parents drive way and the back roads I take to work. I am already scraping the K-member on the ground in a couple of places. I would like to put the 35/22 sway bars on the car and get some good shocks. I have heard koni's are good. Any suggestions on shocks?
10-18-2007, 10:11 PM
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Shocks are easy. Koni SAs in the front with 3rd gen Koni SA Sport shocks in the rear make a good combo. The 4th gen rears are easier to adjust, but have a smaller piston. Either rear shock should be fine. In practice, only the soft end of the rear adjustment range is useful anyway. In practice, you'll probably only use the two softest settings on the 3rd gen rears, and fine-tune with the fronts. I have used the 3rd stiffest setting, but my PHR is lowered a little bit.
