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Old 10-18-2009, 08:52 PM   #1
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Default Unpredictable behavior on carpet. Help!

Hey guys,

I had my first ever carpet race (13.5 rubber) yesterday at a local track, and I had an interesting problem that I couldn't figure out. I was wondering if you guys could give me a hand figuring it out.

The problem I had was that 1 or 2 minutes into the race, the car would loose rear grip and start spinning out. Funny thing is, at several corners the car still pushed .

I tried quite a few things to alleviate the problem; I tried decreasing the amount of physical steering, putting the thickest sway bar up front, removing the rear sway bar, laying down the rear shocks and putting less camber up front. The changes had no effect on the problem but made the pushing worse .

If went back to the pit, cleaned the tires and went out again, it would drive OK for two minutes or so and then everything would start all over again.


What could it be? The car drove fine on asphalt last weekend. I looked at a carpet rubber setup sheet when I got back but couldn't find anything obvious that was different.


One thing that comes to mind is that the fact I was not using any traction compound. The track was Jack the Gripper only track and I did not have it yesterday. Since on asphalt the car was fine without any traction compound I thought I would be fine. Could that have been the culprit?

I also found out that after each run there was a layer of black gunk / crud buildup on tires that was very hard to clean.



I am fresh out of ideas. Would appreciate any help. What could possibly be causing my problem?
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Old 10-18-2009, 09:39 PM   #2
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It would be helpful if tell what car you are running as well as the entire setup. Also if there is a thread started for your car already you can fine useful info by posting this question there as well.

If your tires are developing a layer of traction compound, it could cause some of the problems that you described. You can also cause that when your tires heat up too much. Hard to say without that other information.
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Old 10-18-2009, 09:41 PM   #3
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This is fairly typical at my local carpet track as well...if there aren't a lot of cars running (especially foam tire classes), the rubber tires cake up with the gunk you described, and not saucing will make the build-up even worse. Clean the tires well (some people use motor spray, I use whatever I am saucing the tires with), then apply the Jack and let it soak for 20 minutes or so. Wipe off the excess and you are ready to go.

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Old 10-18-2009, 09:55 PM   #4
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Quote:
Originally Posted by PrimeAKF11 View Post
Hey guys,

I had my first ever carpet race (13.5 rubber) yesterday at a local track, and I had an interesting problem that I couldn't figure out. I was wondering if you guys could give me a hand figuring it out.

The problem I had was that 1 or 2 minutes into the race, the car would loose rear grip and start spinning out. Funny thing is, at several corners the car still pushed .

I tried quite a few things to alleviate the problem; I tried decreasing the amount of physical steering, putting the thickest sway bar up front, removing the rear sway bar, laying down the rear shocks and putting less camber up front. The changes had no effect on the problem but made the pushing worse .

If went back to the pit, cleaned the tires and went out again, it would drive OK for two minutes or so and then everything would start all over again.


What could it be? The car drove fine on asphalt last weekend. I looked at a carpet rubber setup sheet when I got back but couldn't find anything obvious that was different.


One thing that comes to mind is that the fact I was not using any traction compound. The track was Jack the Gripper only track and I did not have it yesterday. Since on asphalt the car was fine without any traction compound I thought I would be fine. Could that have been the culprit?

I also found out that after each run there was a layer of black gunk / crud buildup on tires that was very hard to clean.



I am fresh out of ideas. Would appreciate any help. What could possibly be causing my problem?

From what you are saying it sounds like you are running a spool I experienced the same issues before and always like ball diffs and one ways. But I finally got a setup to work for me using a spool and I like it.

Next time you go make sure you have jack the gripper and make sure you use it always. That way you can work on your setup while using compound. I believe why your car was getting loose after about 2 min or so was because your front tires got too much traction and was whipping you around. If your car was still pushing on a few of the corners afterwards it was probably because you softened the rear too much or either you had your dual rate cranked to try to get the car to turn in the first place.

I would go back to the starting setup you had, but this time make sure you use compound always and see how it does.
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Old 10-18-2009, 10:14 PM   #5
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This has been an issue on our new track as well. Were still working through it, but some thngs that seem to help:

Clean the tires thouroghly after each run with motor spray.
Sauce full rear tire and half the front. Experiment with how long you sauce.
Try a stiffer setup.
Do everything you can to avoid getting out of the groove.
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