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Need handling tips guys....
Took my car autocrossing. First time. The car has alot of understeer. Even with no brakes applied into the turns the front wheels just slide, they're just not biting. I have a pretty agressive setting on the front sway bar. Rear bar is stock front camber is at 1 degree with a little toe out up front. front tires are Toyo Proxies (street tires). My buddies car (He's an instructor)is setup the same except he has hoosiers. Can the tires make that much of a difference. Even he say's my car seems to have more push than normal. Any of you autocrossers out there have any recommendations on suspension setting changes to give me more bite in the front.
Thanks, Leon 78SC |
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There are a zillion little tuning possibilities here, but you might start by either loosening your front swaybar slightly or tightening the rear (if it's adjustable.) Also, don't want to start ANOTHER tire pressure thread here, but tire pressures can make a huge diff. Yes, tires themselves do too, but you should be able to dial in very respectable and predictable handling with your current tires.
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Did your instructor/friend mention to you what tire pressures to run? Generally to get rid of severe understeer, you would want more tire pressure in front, so a good starting point is to reverse the 'normal' Porsche pressures ... try 35 psi in the front and 28 psi in the rear.
It would also be a good idea to 'loosen up' the front anti-roll bar stiffness, and increase the rear stiffness ... you can do that by going to all poly-graphie bushings on the rear bar. Eventually, I would recommend an adjustable 19 mm or 22 mm rear bar. You should notice a big improvement with the above changes, and you may want to discuss them with your friend ... or maybe not if you want to surprise him! Dick Turner from Lancaster, TX, does Police, Security, and autocross training on a private course, and has a book and video on autocrossing ... you may want to get them to get some useful hints and techniques for the future. Hopefully your introduction to autocrossing was pleasant, even with understeer! ------------------ Warren Hall 1973 911S Targa |
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Of course the tips above are the ones to follow but here's a new learning for me: Tires make a HUGE difference. When I've autocrossed, it is almost comical the difference between the 'stock' classes and the modifieds. When the stock cars run, the engines are barely audible but the tires squeal, squeal squeal. With the modifieds (Hooziers), the engines are making all the noise. the tires are silent.
------------------ '83 SC |
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Thanks for the tips guys. Warren, thanks for the name. I'll try to track down that book and video, and yes, I had a real blast. I live close to Lime rock park in connecticut. I'm going to do all the autocross events that I can this season, and sign up for all of the drivers ed events at Lime rock for next season. Anyone else with tips please chime in, I'll probably try them all. Hoosiers are next on my list.
Thanks, Leon 78SC |
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I am not making fun here, but I read something that I am either misunderstanding, or would happen in a 911. You said that "the front end won't bite, even with the brakes off". This is of course true, even more so if you are are actually applying throttle. If the front end wont bite and the car won't "turn in", you are probably not settling the car beofe entering the corner. possibly also getting back on the gas too early. Try feathering the throttle more and don't rush the exit. As far as a cheap adjustment, try a little more toe out in the front. (the car may get darty at highway speeds though).
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In these driver education events, you have to decide if you want to learn how your car handles at speed or if you want to just drive really fast. There is a difference, and I am as guilty as anyone on driving beyond my limits. Track tires will just take you there that much faster. I had my car at an event in April that had rain, snow, and Ice, and never felt close to the edge of control with high performance street tires. My last event in July, I had warm sunny weather and spun my car 360 with track tires. Did'nt go off the road but I would rather not do that again. I guess my point is that high performance racing compound tires can take you to a higher level, but your margin of error at very high speeds is very slim. It is even worse if you are not absolutely sure of how your car performs at this level. Just be sure how your car handles. Good Luck, Michael.
[This message has been edited by 89911 (edited 09-11-2000).] |
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Michael has a good point, and I don't recommend making any modifications and spending a bunch of money during the first year of your autocross experiences. Play with your tire pressures until you can't make any more improvements, then start learning the best approach to the different course elements. If the course is so tight you stay in first gear the whole time, it isn't a 911 course, it's what I call a '61 Bugeye Sprite/'58 Speedster kind of course, and you will NEVER have a chance for top time of day! If the Sprite/Speedster guy doesn't show up, a guy/gal in a Civic will beat you! Don't get hung up on winning trophies! The idea is to get to know your car and have fun.
Back in the early '70's I knew a guy who had a brand-new '71 914, and got tired of me beating him time after time in my modified Beetle, even though we weren't even in the same class. He didn't have a clue how to get the 914 to handle better ... and he got paranoid about winning a trophy! So he asked around amongst some of his USAF buddies, and bought a race-only Bugeye Sprite on a trailer. Blew the engine first time he took it to an autocross. Spent about $1.5K and three months buying/installing a new, less than full-race engine with help from six or eight guys. Finally did beat me in the modified class, only cost him $5.5K to do it, but no FTOD trophy that year, the 1750 cc, street-driven, Super-90++ '58 Speedster was riding high that year on the short courses, and the '66 Corvette took my fast course events! ------------------ Warren Hall 1973 911S Targa |
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