apex26

My car is a mostly stock C5z, which has been on Michelin PS2s. The alignment was about -2.6 camber front and -1 rear, the max I could get after lowering the car. The last mandatory first run instructor said I could go to advanced, but I'm not ready until I am comfortable really sliding the car around. Decades ago, I had this skill down pat, because as a kid I always drove a Corvette, all winter, and never bought snow tires. My reflexes are still "hyperactive", but now due to snow driving front wheel drive, the ingrained instant instinct is to lift--NOT good! My home track is Watkins Glen, far from ideal for learning to slide the car. I started doing auto-x, which helps, and am concentrating on slower tracks like Pocono infield, with runoff this year to provoke the car and save it over and over. Nannys are off. My front Michelins are worn bald on the outside edge, so o I bought a camber kit, and plan on upping the negative to -3, and maybe 1.5 rear, just for tire preservation. The Michelins are now 295/18 square. I also have a new mounted set of 305 square NTO1's, and a set of broken in Hooser A6's mounted from a buddy who has piles of Hoosier giveaway cheap, and insists I go to slicks. He put me on his T2 315/18 Hoosiers last fall at NJMP and I loved how they felt up on the slip angle, but know it would retard my learning to slide around. Oh, and I had to go to a front BBK, so the stock 17's won't fit on front any more. How did you get to where you are? People may have different routes to the same end, so opinions will differ, but how did YOU get over this hump? The wisdom here is amazing, thanks in advance!

jaa1992

Well you really don't want to "slide" the car.
Here is what I tell my students - pick a corner, any corner
Know your "comfortable entrance speed"
Increase it by a couple miles per hour until the street tires tell you they are losing grip

If you've been doing this long enough you'll get faster in the corners.

Number two - and I do this with "advanced" novices
Drive one lap on the line, next lap entirely on the right side of the track, next lap left side of track. Yea you'pick up OPR, but you will find the limits of the track. Do this a few sessions until you are getting almost the same lap times.

Number three - KNOW all the safe run off areas, by now you should be comfortable.

If you want to go to hosiers, talk to the guys running them on a similar car. Cause they stick like glue - until they don't! There is no warning! Find a sample corner on your home track, ask the fast guys what kind of entrance speed they are carrying, work up to it.

I remember when I went to purple crack and talked with the other guys. "oh yea, we are hitting 100+ going through turn 1". I was like no freaking way, I'm nervous at 75! But I took their advice and started working up and soon I was hitting the entrance at 100+. It takes big brass ones and nerves of steel. Cut 5 seconds off my lap times by increasing my speed through the critical turns.

63Corvette

Good advice

insertclevername

When you say advanced group, I'm taking this to be the advanced/instructors, open passing group.

Your focus is not to learn to slide or drive fast, it's to drive smart. You will NEED to know and watch the corner workers (most hpde solo drivers can't even tell you where the corner stations are). You will NEED to be watching your mirrors, and knowing where you are going to be overtaken without a signal. This could be in a corner (I think this is organization dependent on rules).

In my experience most the drivers in advanced group still give signals, but I have been knocked off apex/line a few times by full on race drivers (Konrad Motorsports ).

No matter how fast you are, that does not limit the ability to be in advanced, it's the mental ability to focus on everything like second nature and be safe.

If I were an instructor, I wouldn't care how much car control one has, if the driver has no idea where he is, and others. How many times have you been stuck behind someone without a point by. That driver isn't being rude, he hasn't looked in his mirror, at all! Yet there he/she is driving solo, so someone signed off on em.

redtopz

There's a difference between hoosier slicks and A6/R6/A7/R7's. The latter are DOT tires that most of us race on. They are very predictable and easy to drive at the limit. Unlike some slicks, they do not suddenly lose grip without warning. They are progressive and forgiving.

How do you know when you are at the limit and getting the most out of your car with the optimal line, braking, mid-corner speed, and throttle application? That's the question that keeps us coming back over and over again looking for those next tenths of a second. But as a beginner or intermediate, I think the most important concept that I had to learn on my own was to trust all 4 tires to get the car through corners, particularly letting the rear tires do their work mid-corner. The rear tires should have as much lateral load on them in corners as the front tires. This is completely different from driving on the street and it's what is meant by "slide" the car. A yaw angle is applied so the front of the car is pointed inside of the direction you are moving and that is what takes confidence and practice to get comfortable with. Once a beginner learns this they will see seconds fall off their lap times. Just remember your job as the driver is to balance the load on the 4 tires to keep the car happy at all times and maximize grip where it counts. You don't want to over-slide the car which might look impressive in videos, but is actually slower and overheats the tires. This is primarily done with the feet keeping the front loaded during corner entry, then transitioning to balancing all 4 tires mid corner, and gradually loading the rear on corner exit. Be smooth with your inputs and always keep your eyes up ahead where you want to go. That's the golden rule.

Bill Dearborn

Don't slide the car around. You aren't running on a dirt track you are on asphalt and the quick way around the corner is when the tire is gripping not sliding. Lots of good advice already but I like coaching students that have become comfortable with the line to start off line corner entries. The idea is you have a line through the corner that is best for you and your car as it is setup and when you go in offline you have to adjust so that by the time you are at mid turn you are back on your perfect line so you roll onto the throttle and exit.

Since your home track is the Glen there are plenty of places where you can do this nicely. Going into T1 is a good place to start. First run down the middle of the track into the turn, you will find you need to brake harder but will come into the natural line through the turn easily. Then practice coming in on the far right which means you have to brake even harder to get onto the line. Carry the brake to the apex of the turn and your normal line then you unwind the steering and roll onto the throttle. You can do something similar at the bus stop. Coming in on the far right requires hard braking and a quick snap to the right of the steering wheel, along with a strong roll onto the throttle followed by a quick correction of the steering back to the left to get to the normal line. Don't do this in 3rd until you have it nailed in 4th. About half way through the turn you will have to lift and reapply throttle to get the car to yaw sufficiently toward the exit but you can pretty much be wide open toward the exit at that point. If the car is sliding you aren't doing it right. Don't forget to unwind the steering as you approach the exit rumble strips on the left and then start your gradual right turn that takes you to about halfway across the old straight and down into the carousel intersecting the line on the far right no later than the emergency vehicle break in the guard rail. Hold that line until you are headed toward the track out point near the entrance to the Chute. Doing that you an go like hell through there and if you have a good set of tires and a proper alignment you an push close to 100 mph in that turn. I have run street tires through there at 90+ without breaking a sweat. Proper walking of the steering back and forth and use of the throttle to modulate rear and front tire slippage really works well there but you need to practice it a lot to get it right.

Turn 6 is a real hoot when you take it on the far left side Vs the normal one car width from the right side. You come down the chute wide open, move to the brakes push them hard and start following the left side line around the turn toward the apex. You will be on the gas to some extent while approaching the apex but as you intersect the normal line you should be able to go wide open and shoot out onto the straight heading to the toe. At the toe you an try entering from the far right which gives you a great braking area because you get a pretty sharp change in elevation that you can use to slow the car and then rotate onto the line and go wide open from there. Same an be done at T8 by going in on the far left, T10 on the far left and T11 on the far right.

Once you get used to doing that you will understand a lot more about those turns and what you an do to get around them fast including how to adjust as the situations change. When you go to another track you will see you also have a different appreciation for the turns there as well.

The C5 is an inherently trailing throttle over steer car. Once you know how to use the throttle properly you can use that trialing throttle to rotate the car into a turn and forget about using power to slide the rear of the car and catch it.

Ahh, just talking about driving the Glen makes me miss it. I sure hope I can figure out a way to get back there this year to drive on the new pavement. It is my favorite track, fast as hell.

Bill

apex26

Very useful pointers all. Maybe I'm putting too much emphasis on it, but you see so many guys lose the back end, fail to correct it, and shoot across to the inside and crash. Yet, the really accomplished guys apply opposite lock, maybe some lift--maybe not, and keep on going. That's the true safety in this, knowing how to come back from 101%, which is what I mean by slide the car. I have no interest in showing off, and know it's slower. So it's that loading of the rear tires a tad too aggressively, and knowing how to save the slide.

insertclevername

OP
How does the balance of the car feel to you? I see you're on 295 square with what looks to be a lot of front camber for streets.

By looking at your setup I would guess the balance is toward oversteer.

If you're spending a lot of time chasing the rear already and like it, great. However you may be able to make some changes to shift the balance toward understeer and gain more confidence while pushing the limits on track.

I had a loose setup for a couple track days and I spent time chasing the rear through corners. The car was quicker around the track by about 3 tenths, but I ended up setting the car with more understeer.

Something to consider, maybe adjusting the balance might give you the experience you are looking for.

apex26

As usual Bill, this is great advice, and some practice exercises that would have never occurred to me. I'll print it and try it to the letter. Even though it's not desirable, how do you tell students to practice fixing a power induced slide, knowing it's bound to happen...

apex26

More great advice. I have not run the square setup except on slicks just once. The 3 year old Michelins were fine, except spooky skitterish in the bumpy esses at the Glen. I began slowly deflating the rears, which settled it down, and the factory balance is great, hoping to preserve that. The car rarely sees the street, so no worries there. Did you just use tire pressure or some other method to change the balance?

Bill Dearborn

That is something that I don't encourage them to do when I am in the car. Being from Binghamton you should have plenty of experience just driving to and from work in the winter. Ice and snow are great for learning car control at speeds slow enough that you stand a better chance of not killing yourself. Autocross is a good way to find out about power on and trailing throttle over steer and making corrections to keep a car straight. STCC probably will do a couple of autocrosses at Cherry Valley Go Kart track and that is a great place to develop some car control expertise. GVC BMW Club Chapter may do some autocrosses there as well. However, they have a rule that if you go 4 off you are done for the day even if it is your first run.

Bill

Bill Dearborn

One thing about balance what tire pressures did you run on track? Another question is what is your rear toe in set at?

Bill

apex26

For track I started at the factory settings 30/30 as I recall, then realized the pressure was way too high hot, so adjusted down to 34/34 hot, which tends to be almost each session. Then, lowered the rears at the Glen slightly (like 2 lb increments) until it felt more planted in the esses. It still feels like less air would grip better. The tow front and rear was stock, slight tow in.

SouthernSon

Not much to add to the aforementioned except be cognizant of the loading and unloading of the suspension. Every driver starts out understanding lateral G's (yaw) but to finesse those last few percentages of control you have to think in 3 dimensions (yaw, pitch and roll). The only way to get a seat of the pants feel for this is track time. The speed sensing will come with experience and, as mentioned, the input from others with similar vehicles. Always ride with someone more experienced when you get the chance. Try to keep up with a faster car observing their line, braking, turning and throttle inputs. I don't know how far Putnam Park is for you but it is absolutely the safest and easiest track to learn all the basics. And, always remember to look far down the track to where you want the vehicle to go. This will address the correct countersteer and correction inputs, the timing of which only comes with experience.

insertclevername

I would suggest trying the mid-high hot ap's (36-42psi) with street radials a little more. For more grip to address balance, raise pressure in 1psi increments to the axle you feel needs more grip. Then lower by .5psi when you aren't feeling gains from adding the 1psi.(ex. you added 2psi and the last 1psi did not give you a benefit, lower by .5psi test, then lower by .25psi test if needed) I typically run .25- 1.5psi more hot in the rear. In my experience this has helped me on corner entry balance. I run more of a slow in fast out, late apex line.

Best thing you can do is first go coarse with your ap settings, try 32psi front rear hot, then 42psi front rear hot. Then try 37psi front rear hot. Take the setting that seemed to run consistent throughout the session. If you take temps across the tires this will be verified with driver feedback and data from the tire temps. Say you pick the 37 psi hot, now analysis the balance from your feedback. If you are getting understeer (it could be you are entering too fast, amongst other) try either lowering your rear ap, or raising the front ap, just use the same adjustment increments I explained earlier. Opposite goes for oversteer. There's only so far you can go with this. Each tire will have a unique spot. Once you go over it, you will need to come back down. It comes down to slip angle vs effective spring rate with adjusting ap. They work against each other.

Quote Andy Hollis
"It really depends on the tire in question, the rim being used, the weight of the car, and the alignment, among other things.

In general, increasing pressure does this:

1) Increases effective spring rate of the tire
2) Increases the amount of sidewall support
3) Increases the tire center support
4) Decreases the slip angle that the tire runs at

Decreasing pressure does the opposite.

#1 and #4 work against each other. For example, adding more air to the rear will up the rear spring rate compared to the front which makes the car tend more towards oversteer. But oversteer is defined as the condition where the rear slip angle is larger than the front (taken to an extreme, the rear slip angle goes to infinity). So more air also brings the rear slip angle in line. But the slip angle bit only works within a range whereas the spring rate bit has more range of adjustment.

#2 and #3 have to do with the shape and deformation of the contact patch. The optimal air pressure will have enough air so that the sidewall is properly supported (no excessive rollover) and that the center is equally supported. In this regard, adding air pressure will decrease sidewall rollover up to a point, then nothing. So you need at least enough air to keep the sidewall supported. Adding air will also the "height" of the tire center. You want enough air to equalize that support relative to the tire's edges.

Optimizing the contact patch is especially important for tires with lousy sidewalls (i.e. many street tires), tires that are under-rimmed (e.g. 225 Hoosier on a 6" rim), or tires with less-stiff belt packages (e.g. Hoosier)

So, there is no one answer. It really does depend a lot on your situation. The best answer is to test. That way its your car, your tires, your surface, your courses, and your driving. Trying drastically different air pressures is one of the easiest and cheapest kinds of testing you can do.

--Andy"

apex26

This is rich with such high quality information it will help countless others trying to refine their driving. Thanks for taking the time to help those behind you. Putnam park is to far away but Pocono is close and similar--you'd have to try hard to hit something. I've come to realize I'm entering corners too fast and can't safely put down power after the apex because the car is on the hairy edge of grip on the arch. There's simply no grip available to transfer to power--so slow down a tad and safely practice progressive power at about apex. As for the tire info--there's so much there to process--the notion that slip angle is ADJUSTABLE with pressure is like a light bulb going on. Again, notes taken of tips to practice and refine. Great stuff!

63Corvette

Every time Dad takes me to the track to get some seat time in he has me read every thread on the forum and then quizzes me after. So, wish me luck. We're off to TWS this weekend.
--- Sarah (the daughter)

PS....Sarah Soloed by CHIN on Sunday:-)
Dad

SunnydayDILYSI

Most folks don't think twice about it, but getting mentally prepared for a track day is huge. I like to go out to a high speed kart track the night before to practice driving at the limit and beyond (much lower cost if you don't catch it vs a vette at the Glen). It builds confidence and gets you ready for the real thing. Also look into prep exercises in "Ultimate Speed Secrets" the book. This will improve your lap times by a huge margin on stock hardware with NT-05s vs all the mods you listed above without mental prep. Once you have fully plateaued on lap times (within .2 second lap after lap) look into the hardware.

NT4HIM

Sounds like good advice to me and exactly what I'm doing to prep for this weekend at TWS. Look me up and we can compare notes. I'm the blue C7 in garage 2. We lady vet drivers need to stick together, and I know your dad will have great instructions.

Daveselim

Great information here. Also Bill Dearborn. Thanks

Now that I think about it I am still pretty novice but understand the concept of yaw as you describe it. I cannot for the life of me do it on the track. I realize the key is more seat time and practice.

But thanks for explaining the concept so clear. This gives me something to work on this year. In small increments of course.

Of course I stumble into a decent turn every once in a while and think, hey that felt good, what did I do.

I am the guy that slows way down before the corner and rolls through it slowly while getting passed. I can slide my off road vehicles under control very easily but can't seem to figure out this proper techique on track. (i.e. not sliding) I think it is fear of driving the car versus offroad vehicle. I marvel at the guys that can take a relatively stock car and turn it quickly through the corner while observing the proper yaw as they leave me behind.

My buddies suggested that I need a cheaper car to practice. Or maybe a go-kart. They have (fast) karting rentals at my local track. Do you think I can learn this concept by Karting? Everyone has told me yes.