Race gurus, share thy wisdom on under-steering

I've read the archives on this issue but can't draw any definitive conclusions. Simple sceanrio is this: There is this sweeping curve near my house that I can take easily in just about any car at around 40 mph. In the 911, I can take it around 50 but at that point, I feel the car "skipping" to the outside of the curve. I feel that should be more of a difference between a Porsche and any other (reasonably sporty) car. How do I stop this understeering? Row suspension? Angle of attack? Throttle gymnastics? Tire pressures (I follow the factory guidelines on them)? What say thou...

Understeer can be caused by three major things... Driver, Car, road Taking the wrong line and or doing the wrong things can induce understeer. Car set-up. Most street cars even Porsches are set-up to have just a bit of understeer built in. The theory is that understeer is safe. Road conditions can play a big role in how car handles. In reality road race car set-up is always a balance and rarely can a car be made perfect for every corner. The best teams just learn WHICH corners are the one to set-up the car for to be fast overall or to overtake. In the rest it is just up to the driver to "do their best". Sounds complicated right? Well it is! Best place to start is autocross and Driver's Ed. (If you have not already). Here you will learn what the car wants to do in various types of corners and what you can do as a driver to improve it. After this type experience you will start to have some idea as to what best to do to your car to make it feel the way you want. <img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" />

If you are using the factory pressures of 36/44 I would start there. But seriously the street is not the place to test these types of things. Head to the track.

All sorts of things come to mind but first is.........you are diving a Pcar in Chicagoland, in the winter.......if you are running summer Z rubber, then we needn't go further. On the other hand, even all-season rubber on dusty salt-covered pavement isn't the greatest scenario.

Besides ther lifelong learning process of improving our skills, you can start by ROWM030 which besides improving handling, it reduces understeer tendency (unlike US MO30), a set of grippy S03's, and also lower the tire pressures bellow recommended, I drop 2-3 psi on my 18" sport designs. 25% increase in curb speed over other reasonably sporty cars in a slow bend is not bad anyway...after all you are also braking later into the bend and stepping on the gas earlier on the way out too

As Greg says, tire pressure is the place to start. (conventional wisdom for a 993 is approx 34F-36R and varies by tire make, not sure about a 996) But the street isn't the place to do your testing. Join the local PCA region. there is an autocross school on april 27th. Should help a lot, in terms of figuring out your car. I hope to work that schedule permiting. There are track events at Blackhawk in early may -- one day for novices, the next week for experienced drivers (or vice versa). that's a great way to try different things to dial in your suspension to your liking. You should be able to get to a set-up you like without pouring a lot of money into suspension mods. That said, mods are the next level of fun

As it's been mentioned, several things contribute to under or oversteer. The primary factor one needs to understand is weight transfer from front to rear (or vice versa) and corner to corner. The best way for me to start learning basic car handling has been to first read about it, then attend local DE events. The DE events are the most fun. I also participate in go-kart events when ever I find time, and that really makes you understand the car dynamics and control. My first suggestion for books is Vic Elford's Porsche Performance Driving, and then Skip Barber's Going Faster. I personally learned more from Elford's book than the Skip's but Skip's also gets in to some other details that Elford does not touch on. Good luck.

It hasn't snowed here for a while and the weather was nice so I pushed it the other day. But the point to experiment on the track is very valid and understood. I've just joined PCA in Chicago and am most definitely looking to attend the novice day at the tracks to figure things out. Meanwhile, I'll lower the pressures by couple of psi all around and pray for an early spring! I'll also drop by a bookstore to pick up the Elford book on driving faster. On a sidenote, I don't know how people go thru the winter w/o driving their Porsche. The maximum I have ever gone is 7 days and it just kills to look outside the window and see another 'no porsche day' in the making <img border="0" title="" alt="[Frown]" src="frown.gif" />

Chi996 Elford's book is currently on sale at Classic Motorbooks [phone removed] for 1/2 price $10.98 (no affiliation, but I did enjoy the book) Mike

I drive my ttX50 frequently in Chicago winter weather, and in fact drove it a lot yesterday and today (temps 26-36). The roads are icy in places and wet in places. Traction is no problem. For the typical track-inexperienced driver, severe understeer is generally a problem of early apex. If you consciously apex late (like 2/3 of the way thru the corner) you accomplish 2 things. First, you can let the car take a "set" can then accelerate out of the corner. Second, you give yourself lots of room at the outside on exit. On the track, you know you've apexed too late if you're leaving room on exit, or you're tricking the car into oversteer. On the street, all the extra room is safety margin, which you definitely need. Having said all that, if you are really getting the car to skip over the bumps, you're going too fast for the street. Lastly, a 10mph difference thru a 40 mph corner is HUGE. Even 1 mph difference on exit speeds leads to a huge gap on on entry to the next corner if there is any significant straight in between. If you figure it out at 60 vs 61 mph, each extra mph is one foot per second, so every 10 seconds opens up a 1/2 car length gap. On a track, it's insurmountable. If you're 10 mph faster (50 vs 40) that's 73 ft/sec vs 58 ft/sec, so you're opening up a gap of 15 feet every second. That's a car length a second. If you want that gap to be substantially larger, you're going to need suspension, driving lessons, and race slicks. By the way, if you want all the practice in the world, why not come to Gingerman on Tues., Wed., or Thurs. nights. It's all the track time you can possibly stand for $50.00. It's about 2 hrs from downtown Chicago if you leave before rush hour. Hope to see you there. AS

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Alexander Stemer: <strong> On the track, you know you've apexed too late if you're leaving room on exit, or you're tricking the car into oversteer. </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">What do you do to "trick" your car into oversteer? I tried some candy but that didn't work. Suggestions appreciated.

Greg, with the cars you have, you're certainly the oversteer "meister". I'm curious about the 97 RS since I've never driven one. How tolerant is the car of throttle lift in a corner? Can the car be trail braked? I enjoyed a great afternoon with a Bondurant instructor, I think his name is Chris Cook, at Gingerman. He showed me how to trick his rental Taurus into oversteer, full 4 wheel drifts, and mid track 180's. Then he pointed out what I was doing in my Elise 190R that overaccentuated oversteer in my car. That guy is so good, you would swear he'd given the car candy. But then he was Tony Stewart's road course coach, so I guess he knew a thing or two. Tell us about the RS. AS

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Greg Fishman: <strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Alexander Stemer: <strong> On the track, you know you've apexed too late if you're leaving room on exit, or you're tricking the car into oversteer. </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">What do you do to "trick" your car into oversteer? I tried some candy but that didn't work. Suggestions appreciated.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva"> : Candy's dandy.... but... LIQUOR'S QUICKER :