ZDan

Major part of your problem. Don't "adjust" anything until you get out there on some real trackworthy tires.

Street/track usage?
Have them maximize front camber (up to ~2.5 degrees, anyway), ~2-2.5 degrees rear camber, zero to maybe 0.2degrees total toe out up front, ~0.1 to 0.2 degrees total toe-in in back.

"Factory spec" is a very broad range, and not ideal for track usage anyway. Most importantly to reduce understeer, make sure front camber is maxed (assuming stock suspension), and rear toe-in is minimized.

Despite posts indicating the opposite above, getting ON the power generally induces UNDERsteer, and getting OFF the power or on the brakes generally induces OVERsteer. The idea is to trail-brake into corners, which will help turn-in MASSIVELY. As you get on the power exiting the car will NATURALLY tend to understeer to track-out. This is performance driving 101, folks...

ZDan

Turning in while still braking (this is the right thing to do btw) gives OVERsteer, not understeer.

As a driving instructor, I *totally* disagree. Doing all braking in a straight line, getting OFF the brakes, and THEN turning into a corner will give exactly what this guy is experiencing: UNDERsteer.

I expect my students to trail-brake from the get go. The car behaves MUCH more naturally. Trying to force students to do all braking in a straight line only hinders progress. Even "oversteery" cars like the AP1 will not want to turn in without some trail-braking.

Exactly. And most people do this a lot more easily and naturally than trying to do ALL braking in a straight line and then try to turn in with zero braking.

I suspect that his understeer could be the result of lack of trail-braking.

I just HATE to hear people being instructed to "brake in a straight line", or the idea that trail-braking is an "advanced technique". It's way way WAY easier and more natural-feeling to students to trail-brake than to try to turn in completely off the brakes!

At a ZCar Convention AutoX day one year, a friend's wife was having difficulty in their 350Z, having been out with her husband and another track driver (both non-instructors), so they asked me to go out with her. After the VERY FIRST TURN, which she executed perfectly well for a beginner, she apologized for "not braking in a straight line"! They had been FORCING her to not trail-brake! I told her that she did the corner entry fine, that she's *supposed* to turn in while still on the brakes, and basically didn't have to say anything else. She went 2 seconds faster and had a MUCH easier time doing it.

saving4one

I went auto-xing for the first time this year and was understeering quite a bit (stock rims+tires on an '03 with Eibach sway bars set to softer setting). The tech guy told me to up my tire pressure by 10 lbs all the way around and wow what a difference. For the rest of the season I just played with tire pressure to find the best balance. I would try tire pressure first for an easy no-cash adjustment. Next season I'll start to adjust my sway bars and get R compound tires.

ZDan

What works for autoX might not for track driving. At the track, you'll gain ~8-10psi from heat, a lot more than you'll gain in an autoX run. For me, ~28-32psi puts the tires at a conservatively high 38-40psi hot. If he adds 10psi to standard cold pressure and runs 42psi cold, that would almost certainly put him *way* beyond the ideal pressure range once warmed up.

S000M

Ok, got some good stuff here. My car is not loose. I've been driving it for 5+years now. Prior to this I never auto-cross or tracked my car. I like to think I understand all of the dynamics involved in the discussions here. I know I don't have the best tires for tracking this thing but I'm stuck with them for now. I'm sure they are part of the problem. I probably need more camber, but I won't know that till I get it on an alingment rack & see where it's at now and go from there. And I like the trail braking idea. I can see where that would reduce understeer if done properly. As for tire pressure, nix the idea of increasing pressure. The heat builds up pressure fast on the track. On my first run I almost spun it in a hairpin because tire pressure went too high on rears. I dropped them a good 4 lbs and it was much better, a little less in fronts.

I appreciate all the input. You all make good points. Now it's up to me to sort through it all and make adjustments, or not, accordingly. Next time I know what to expect. I'm planning another go at it January.

Thanks again

austincrx

Look man, it's all relative. Braking at 100% into a corner and not turning in SMOOTHLY will cause understeer. Seeing as how he has only been on the track once, he's probably not as smooth as you or I am (I've been racing cars for the better part of a decade, I don't know everything, but I only try to offer some suggestions based on my own previous experiences).

About the trail braking, yes, that is much faster, but if you're a first-timer (or second timer) shouldn't you be worrying about car control and not crashing first, then once that's down you can look into going faster? I'm glad I had an instructor that taught me very good car control skills first, then taught me how to go fast.

Lets go for an example here to help my point: If you teach student Joe, on his first time out, that he needs to go faster into the corner, push it, push it, etc. Then maybe he has some good, fast lap times, but what happens after he over-cooks a corner and starts to get sideways. What if he doesn't know how to control a slide, what if he's in over his head. He instinctively and suddenly lets off the gas, the car catches and spins the opposite direction, he slides off passenger side first into a tire wall, his car is totalled, his day ended, and the reason is because his instructor didn't take a little time to teach him good car control first, or atleast make sure he knows how to control his car before getting him to drive the car on the limit of it's abilities.

Just some food for thought. You are correct about trail braking, it's faster in a lot of cases.

Edit: Atleast we agree on one thing: the tires up around 36+ psi is WAY too high. Depending on what type of tires (race tires build heat more than street tires, although all tires will build some heat), I wouldn't want hot pressures to be more than 40-ish psi. I know the Hoosiers I run will build 10-12 psi on the drive tires and only 7-9 on the non drive tires. I think the last time I took my street car to a track day I didn't see that much pressure increas on street tires, but that was 3 years ago.

ZDan

You are right, still being hard on the brakes can induce understeer at turn-in, but I honestly can't think of a time that's happened at the track, driving or instructing, except in the wet.

Also worth mentioning that simply entering with too much speed will give apparent understeer, so to the OP, part of the answer is very likely "slower in, faster out". If you're not making the apex, brake earlier, possibly turn in earlier as well, with less speed, and MAKE that apex.

For me, trail braking is a critical part of car control and smooth driving. In my experience, students often do it somewhat naturally anyway. I don't do anything to discourage this unless they do something obviously wrong like stab the brakes mid-corner. I always preach trading braking for steering input, never "only brake in a straight line" (which I think only hinders progress and makes the car more difficult to drive).

That's not my approach at all. Start out slowish, somewhat below the limits of course! Then initiate braking later and later as progress is demonstrated.

I've had some students that did get fast very quickly, most do not. For sure, the ones that developed quickly had already demonstrated good car control before they were actually doing relatively fast laps. It's a prerequisite.

Again, I'm not trying to get people to overcook it into corners, but I am all about having them trail-brake very early on, from the first turn of their first lap is fine.
Trail-braking *is* good car control, it's practically required to get the car to turn in. I will never sign a student off to solo until he demonstrates excellent car control and can consistently drive right at the limits and repeatedly demonstrates proper responses to loss of grip. If he's not trail-braking, he's not there yet and doesn't get signed off by me.
Over the past 10 years as an instructor, I've had students spin, never had one damage sheet metal.

Faster and *easier* as well! Again, I'm *not* talking about king-of-the-late-brakers stuff here. Just allowing the students to trail the brakes past turn-in, which is the natural way. I'm sure most instructors do this whether they realize it or not. Imagine forcing a driver to do literally ALL braking in a straight line, then he has to jump completely OFF the brakes, and only *then* can he initiate the turn. That's slower, and it's also much HARDER to do consistently, and the car will NOT want to turn in at all!

Probably depends on the tires. Interestingly, in both the 240Z and the S2000, on Extreme Perf street tires or track tires, I get about +12psi on the rears, +10 on the fronts. I usually start out with 30-32 front, 28-30 rear and then bleed down to 38 hot (which is pretty conservative for most tires).