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Discussion Starter #1
Hopefully this is a good place to ask how to cut down on the rear end breaking loose in AX. I have a GXP with, DDM backbone, LV brace, probeam and ZOK front and rear swaybars running on RE -1 tires. I've tried lowering tire pressure, but does not seem to help. The AX course I run is fairly small with allot of tight turns. Any ideas would be appreciated.
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Gypsy1Sol
 

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Two things. If you don't have grippy tires, get them. Michelin Pilot Super Sports or Dunlop Direzza Star Specs are good choices.

Second is change the wheel alignment. DDM did mine and it both eliminated most of the understeer but also hooked up the rear better.

After that, it is driver skills. Gently apply throttle and plan for the boost kicking in. Especially on tight corners, make sure your front wheels are straight before giving it gas.

It takes some learning. I have been autocrossing for several years and this is the first year I haven't spun it .... so far!

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Forgot to say about the alignment search this site for posts by SnaponBob onwhat he did. He gives specs.

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Discussion Starter #4
Thanks for the advice. I'll check into the alignment and continue to practice. Timing the turbo on a short course is a challenge also.
 

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Was at the Maryland mod meet on the weekend and had my alignment set by DDM. Totally different car as before every time I went hard into a corner the rear end wanted to rotate around. Not any more, turns out my rears were toed out 3/16"

Before spending money for tires, have the alignment done by someone that knows what they are doing. If nothing else, it'll make the new rubber last longer.
 

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Hopefully this is a good place to ask how to cut down on the rear end breaking loose in AX. I have a GXP with, DDM backbone, LV brace, probeam and ZOK front and rear swaybars running on RE -1 tires. I've tried lowering tire pressure, but does not seem to help. __________________
Gypsy1Sol
Gypsy - lowering the rear pressure is exactly the wrong thing to do if you are suffering from oversteer. RAISE the rear tire pressure a few psi (maybe 3 to start with) and go drive around in tight circles in a big parking lot and see what happens. There will be a point of diminishing returns, but I think you'll find that this will work for you.

Once you find out what front rear differentialk works for you, note it down for future use. Each course will be a little different and weather and temperature will affect things as well, but if you are experiencing mild oversteer, the higher rear pressure should reduce that and balance the car a bit better. And don't forget that you can pick up 10 psi between cold and after you've run the car a couple of times.

If you have incorrectly set toe or camber etc., that would have to be addressed, otherwise you are just 'bandaiding' the situation, but often a small pressure differential is all you need (it's what we always do on the race track every time we go out).

Other than pressure, there isn't a lot you can do unless you buy a tiore pyrometer and start learning about temperatures and what they mean, and then do fine alignment adjustments based on that data.
 

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Discussion Starter #11
Thanks for your input. I've run the rear tire pressure as high as 40# without much help. I'll have to look up my alignment specs when I've time. If memory serves I got the specs from Krazed Kanary or one of the other AX drivers. The alignment guy is a racer so I did not get much of an argument from him, just the store owner. I'll continue to play with the tire pressures and try to tune them to the course, mindful of temperature and other conditions. Thanks again for the help.
 

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Hopefully this is a good place to ask how to cut down on the rear end breaking loose in AX. I have a GXP with, DDM backbone, LV brace, probeam and ZOK front and rear swaybars running on RE -1 tires. I've tried lowering tire pressure, but does not seem to help. The AX course I run is fairly small with allot of tight turns. Any ideas would be appreciated.
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Gypsy1Sol
You didn't mention if you have the factory authorized reflash for your turbo setup so I will assume that you do which means you have approx 310 hp on tap for a rather lightweight vehicle. I am running the DDM stage II supercharger with similar HP available at the rear wheels. Going by your setup it appears that you have a really stiff chassis and suspension if you are running the DDM backbone, LV brace, probeam and Z0K bars which inevitably means that when cornering hard (such as on tight small courses) that you are overloading your tires initially with understeer (this is an assumption)followed by some counter steering and then induced power on oversteer by punching the throttle (which happens a lot on small tight courses because most drivers lose patience in tight turns and just want to get on the throttle as soon as possible). Learning to control the throttle by squeezing the pedal in a rapid but increasing pressure manner will produce better results versus treating the throttle like an on/off switch and mashing it to the floor when you want to get on the gas. When running Hoosiers I've been running 32 psi in the front and 28 psi in the rear. The car is light enough to operate at those tire pressures without much rollover at all. Reducing the psi in the rear will help with reducing oversteer (think about drag racing where a softer tire grips better on launch), but be careful about rolling the tire over on hard corners. Also New England has colder pavement temps than others do nationally...especially this time of year, so there isn't much grip to begin with. I run -1.8 front and -1.2 rear degrees of camber on my car (it's also a daily driver) and have good success with those settings and it's not too harsh of a street setup and is somewhat easy on tires. Good luck.
 

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Hopefully this is a good place to ask how to cut down on the rear end breaking loose in AX. I have a GXP with, DDM backbone, LV brace, probeam and ZOK front and rear swaybars running on RE -1 tires. I've tried lowering tire pressure, but does not seem to help. The AX course I run is fairly small with allot of tight turns. Any ideas would be appreciated.
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Gypsy1Sol
I will second what wspohn wrote about tire pressures. More pressure in the rear tires in relation to what the front air pressure is. There are several things that will make your car loose and your right foot is one of them. Assuming you have already have an AX alignment with a bit of rear toe in there will be a few things you can do to cure your oversteer condition.

1. 5 lbs more psi in the rear vs the front.
2. Stiffer front sway bar. Drill another hole in your ZOK bar.
3. Softer stock FE2 rear bar or just loosen or disconnect your rear ZOK sway bar.
4. More rear toe in.
5. Do you have dual adjustable shocks? More front compression and/or less rear rebound.
6. Less front to rear rake so your car corners out at 51/49 percentage of car weight front to rear.
7. Brake sooner and roll back into the throttle sooner and get your front tires pointing straight ahead before using full throttle.

One or more of these suggestions will help you. Good luck.
 

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Considering tires are probably the most important part of the equation for AX, on the solstice with a proper set up and inherent specs it is quite neutral, I found it very odd the OP has never mentioned anything. He may still be stock (crazy, but like me unfortunately). Is he stock, high performance, new, old, DOT race, slick, oversize and if so how much, etc, etc. Until then I would recommend considering all recommendations so far as secondary.
 

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He posted he was running RE-1 tires, or at least that is what he/she seems to post.
 
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