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Another day at the track, but with rain..help with understeer

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Old 10-23-2010, 02:23 PM
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wtfpenguin
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Default Another day at the track, but with rain..help with understeer

I went to thunderhill yesterday and was dreading the rain and it was dry until my last run.

The car was on rails for the most part, running cheap street tires and they held up okay at best, once they got hot they were really mushy, but other than the tires the car handled great. For suspension I have stock shocks and H&R springs and bbs re 18s 225f/265r.

Anyways on the last run it was starting to rain, and the track was damp. Coming down the front straight usually around 125 and into turn 1 at 80-85. It was wet so I decided to take it slower, and gradually work my way up to speed. As I'm turning in ever so gently the front is just sliding, and sliding, and I slowly lift off the throttle as I put 4 wheels off the track, and then continued back on track, just took the turn extremely wide.

Next time around I'm going into turn 3, medium throttle, and the car is just being pushed to the outside of the turn, as I'm turning into the apex the car wants to go the opposite way. And more throttle just makes it understeer more. So I slowly lift off the throttle, and then bam oversteer, so I get back on the gas and correct.

Any advice for driving these cars in the rain? If I had gone out again I would have probably lowered the tire pressure in the front, but anything I could change with my driving style?
Old 10-23-2010, 02:35 PM
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SleepRM3
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Yes these cars are tricky to drive in the wet. They're set up for understeer (stable situation). The wet conditions make the understeer worse, and occur at lower speeds. You'll need to be very smooth with your steeering, braking, and throttle inputs (squeezing and releasing the brake and gas inputs), and be ready to correct with opposite lock. Remember that after you catch the slide with opposite steering lock, turn the steering wheel back to the neutral position at the "pause" (when you catch the slide), otherwise--the rear end will swing back in the opposite direction resulting in the laughable "tank-slapper" pendulum slide series (ha ha).
Old 10-24-2010, 05:27 AM
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i was thinking what if I went into the turn fast and lifted to get the rear to come out and then get on the gas. Kind of like putting it in a controlled slide.
Old 10-24-2010, 06:52 AM
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I wouldn't set that as my goal, trailbrake more aggressively/turn in as you're coming off the brakes. You can still powerslide out of them if that's too boring. :P
Old 10-24-2010, 07:09 AM
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Originally Posted by wtfpenguin
i was thinking what if I went into the turn fast and lifted to get the rear to come out and then get on the gas. Kind of like putting it in a controlled slide.
Definitely NOT the way to deal with understeer!
Old 10-26-2010, 07:30 PM
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thinking about putting 245s up front...thoughts?
Old 10-26-2010, 07:45 PM
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A friend of mine was complaining about how his 996 (GT3 coil overs/sways) was understeering @ VIR turn 1. He's an intermediate student. I'm an instructor and occasionally do time trials, anyway I had the car oversteering through the same turn, without much of an effort. He wasn't happy with the way his car drove until he put different tires on it. I thought there was an improvement with tires also, but I thought the set up was just dandy before the tires as well.

It's like any other car, the more traction you want from the tires, the more weight there needs to be on them. Better/more tire will help, but really driving technique is what you probably need to work on. Think about the weight distribution of the car, it's already pretty oversteer prone despite Porsche's best efforts to mask it. We're not F1 drivers here, but I assume since you're asking this question, you're a pretty decent driver, so I don't feel bad suggesting you do more turning while still on the brakes. The 996 rotates pretty well.
Old 10-27-2010, 03:46 AM
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Adjustable Swaybars can also help with this.
Old 10-27-2010, 11:30 AM
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Too many variables but most likely just the rain mixing it up with whatever oil was on the track as it had just started raining. Certainly the larger front tires will help with understeer, but you really need adjustable sway bars to tune for rain or just disconnect them altogether....

Also you want sufficient tire pressure in the rain not less. Higher pressure opens up the treads and grooves allowing them to displace more water....
Old 10-27-2010, 11:50 AM
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Originally Posted by Ahmet
It's like any other car, the more traction you want from the tires, the more weight there needs to be on them. Better/more tire will help, but really driving technique is what you probably need to work on. Think about the weight distribution of the car, it's already pretty oversteer prone despite Porsche's best efforts to mask it. We're not F1 drivers here, but I assume since you're asking this question, you're a pretty decent driver, so I don't feel bad suggesting you do more turning while still on the brakes. The 996 rotates pretty well.
Agreed.

Keith Code's motorcycle books have a very heavy emphasis on contact patch management and understanding how every action and reaction effects what each tire is doing. Obviously it's much more critical on a bike but I found my bike background very helpful when I transitioned to the 996. They're a very good read in my opinion even if you're not tracking a bike.
Old 10-27-2010, 07:10 PM
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I'll adjust my driving style next time I go out and trailbrake. I remember watching a 7gt3 coming around in the rain, and he was hitting the brakes mid turn. I'm going to laguna seca on monday, so I really hope it's not raining, there isn't a lot of places to go off track.
Old 10-27-2010, 09:36 PM
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Originally Posted by wtfpenguin
I'll adjust my driving style next time I go out and trailbrake. I remember watching a 7gt3 coming around in the rain, and he was hitting the brakes mid turn. I'm going to laguna seca on monday, so I really hope it's not raining, there isn't a lot of places to go off track.
If it's wet stay off the blue & white gators.....
Old 11-02-2010, 02:59 AM
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Just got home from Laguna Seca, what a beautiful day!

Other than getting the meatball after the 3rd lap on my first run, 94.5db, then the girlfriend tagging along, wanting to go for a ride, then having a panic attack on my second run, I finally got the track down after lunch. It was my first time at Seca, and I was watching a lot of the other drivers if and where they brake after the corkscrew into turn 9.

Most people didn't brake. So I tested more gas down the hill trailbraking into the turn. I don't know if other people get annoyed when someone is braking where they normally don't.

Anyways I understeered 95% of the time out of turn 9, and if I slightly lift throttle it snap oversteers, same with turn 2 (the hairpin). I don't know if this driving style, or if I should start looking at sways and bigger tires for the spring. Would a lack of LSD have anything to do with the understeer?

Turn 9 scares me silly!
Old 11-02-2010, 03:28 AM
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I had a Lotus spin out and stop on track at the bottom of the corkscrew last time I was there! :O Awesome track none the less.

Sorry that you continued to have understeer issues, hitting the brakes mid turn is obviously not the elegant way to handle things. Of course car set up can help, (most LSDs will actually increase understeer on power), having been in your shoes, I still say you ought to be able to drive around it. The 996 is very eager to rotate, though once you get past ~85% of the car's abilities, it takes some finesse but it's oh so rewarding!

If you make it to the east coast, I'd be happy to have you jump in for a ride or go in your car, I plan to instruct more regularly again this year. Have you had instructor input? The last event I ran out west, most hadn't even heard of instructors on track...
Old 11-02-2010, 04:40 AM
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at the auto-x the instructor had a 993, and I learned A LOT that day.

The next track day the instructor had an m3, and the next time a mcoupe. The rear engine is WAY different in my experience.


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