M758

I once drove my car in track with 3 old tires and 1 really old tire. Result was really bad understeer in right turns. The course had mostly lefts so the understeer only hurt me in a couple spots. IN one spot I just had to slow down. In the other I adjusted my line to allow the car to slide a bit more on that tire and worked hard to rotate the car a bit more. The idea was to simply allow to slide a bit and still have the car placed properly.

In the end I was able to make reasonble speed there, but that entire effort was really a band-aid on the real problem. Given I was there as an instructor and wanted to a little "driver training" vs car testing it was fine for that day.

The right fix was to fix the understeer, but as you know in racing sometimes you need to learn how to race an ill-handling car.


In hindsight the adjustment to my line where probably in the 3-5 feet anyway.

Larry Herman

Man, there's a lot of good info condensed in this thread. How to judge when you've got the right apex point, the attitude of your car at the apex, how to handle a series of turns, etc. One item that I can add is that you need to have early power in order to have exit speed. By that I mean you want to take a line where you can floor the gas as soon as possible. For me, in most corners, that means the transfer from the brake to the gas is to the floor. Easy to do in a low HP car; much tougher but just as necessary in a high HP one.

I find that there are more than a few experienced drivers who slowly feed the gas to the floor, sometimes not getting there until well after the apex. This is not only slow IMHO, it leads to a false sense of where to apex. I find that these drivers tend to apex too early, and then compensate by feeding in the power even more slowly. First thing we do is to go deep, turn the car hard, and floor it. Then as they begin to get it, we start turning in earlier and apexing earlier until we start running out of track.

TD in DC

The way I have been driving the '44 lately is that I am on full throttle nearly immediately after turn-in. Of course, I have been working on increasing entry speed and I really am braking way less than I used to going into corners. Nonetheless, an instructor who looked at my data recently noticed how soon I was on the gas, and told me that if I can get back on full gas before the apex, it just means that I can enter the corner faster. Her theory is that unless I am modulating the throttle with that "oh God . . . I'm not gonna make it" feeling at least until the apex, I have overslowed before corner entry. What say you?

I totally agree that it is easy to be on full throttle early in a low HP car. Another benefit of a low HP car, though, is that I can hear/feel the engine straining, which helps make me realize what actions scrub speed and slow the car (e.g., not opening the wheel early enough . . .)

Larry Herman

Well, I disagree with her. With 150 hp, if you ain't on the gas all the time, you ain't goin' nowhere. Really, why would you want to modulate the throttle up to the apex? Where would that get you more speed? Why would you need to modulate the throttle to get to the apex? It seems to me that if so, you didn't rotate your car enough during corner entry. Maybe she doesn't advocate trail braking and so every approach to the apex is fraught with understeer. Get her to explain why she feels this way.

TD in DC

She says that the fact that I can get back on the gas so quickly is de facto evidence that I overslowed, sacrificing speed in the braking zone and slowing below the limit, which she says is the only reason I am able to be on full gas immediately after turn in. She says that the fastest way is to be at the limit all the way through the corner, which she says necesssarily will result in some period during the corner when I cannot get back on the gas so quickly/fully.

SundayDriver

What a load of $&^%
Different corners demad different things. Let her try that in T6 at Laguna (but make sure she takes video - I love to watch good crashes). You just can't throw absolutes around like that. Yes, there are some corners where that is true but going for all the entry speed is where the real danger is. Does she understand that? (T11 at Mid Ohio when taken fast is a pretty late throttle IF you carry big entry speed and it is high risk.)

What qualifies a DE instructor? You survive enough DE's, get into a training program, which may not be much, prove that you can communicate and teach students to be safe. There is no requirement that DE instructors be able to drive a car turly at its limit or very close to it. IF she holds any REAL lap records (fair number of cars, not a one car event on a seldom used track/config - I know all about those, I hold a few of those too) then she is probably qualified to instruct you how to go really fast.

She would probably go nuts looking at data of lap records in SRF's. Those guys must be making the same mistake.

TD in DC

I agree with you about the fact that every corner is different. It may be inexperience on my part, but I generally feel "better" when I am on the gas -- aggressively -- or on the brakes through the corners. All brakes or all gas, or at least a steady transition from one or the other, is easiest (of course there are corrections, like trying to induce TTO to rotate the car, etc . . . ). I think that is because it is easier to control the weight transfer when you are being deliberate as opposed to trying to "modulate" where the weight is at neither end of the car and thus harder to feel when it is about to transfer rapidly on you . . . Am I making sense?

Now, even if her theory -- or her articulation or my understanding of that theory -- isn't right, I am sure I am leaving time on the table by overslowing still, but I am getting better

Larry Herman

Todd, just think about the friction circle and realize that this is all about, God help me........G Sum
Yep, it's about maximizing the combined lateral and longitudinal G forces of the tires to stay on the edge of the friction circle for as long as possible. Here a typical corner:

1) You squeeze on the brakes up to threshold, maximizing their longitudinal Gs
2) You ease off the brakes and start turning into the corner, shifting some longitudinal Gs for lateral Gs
3) You get to full steering input, off the brakes, and generate maximum lateral Gs. This is the slowest part of the turn, and you are circumscribing the tightest radius at this moment.
4) You start to exceed the grip of the rear tires, the car starts to rotate, and you transition to the gas, full throttle , shifting the weight onto the rear tires, and holding them at their maximum grip.
5) As the car starts to accelerate you will need to unwind the wheel to keep either the front tires at maximum grip (in an understeering condition) or to keep the back tires at maximum grip (in an oversteering condition).
6) As acceleration increases the longitudinal Gs on the rear tires, you will need to decrease the lateral Gs by unwinding the wheel.
7) You get to trackout and the lateral Gs end, and everyone wonders how the hell you got through that turn so fast.

SundayDriver

Something I learned from the guys at the Mid Ohio school (and I posted about it long ago) is to determine which end of the car you drive. Your mind, as you feel the balance, is going to either focus on the front tires or rear.

Force yourself to drive the reat tires. It makes you get on the power sooner and (at least for me) tends to pull my eyes up so that I am watching further down the track.

TD in DC

Maybe I am being dense, but how do you do that?

SundayDriver

It is just a matter of focusing yoiur attention on what the rear tires are doing. Feel the weight tranfer to them, rather than feeling it transfer off the fronts, for example. If you are very aware of the rear tires as you approach the exit of a corner, you will feel that they are not carrying as much weight as they could. You fix that with more throttle.

At this stage, I think you should be going for exit speed, exit speed and more exit speed. Don't worry about entry speed until you are getting all you can at exit.

}{arlequin

that's right td, be a friend of the gators.... if you're not 'there', then you're not there.

for me it's usually... wait, wait...
..... wait... Wait...
.....Wait... WAIT!!!....
....oooooh.... you got premature apexation again....

Z-man

Technically, a pitcher needs to follow-through to ensure his form is proper, similar to how a batter needs to swing through the ball...but I digress...

and
I'm with Todd on this one.

This winter, at our advanced driver's seminar, we had Ross Bently speak. He asked a question, "Do you think Schumi makes less mistakes today than he did years ago?" Bently said that Schumi most likely makes just as many mistakes at he did when he first started racing. The big difference is that he's correcting those mistakes far sooner:
- A typical newbie driver doesn't realize he's off the apex until he's past the apex - at that point, his corrections are typically futile, especially if he's carrying too much speed into the corner.
- An intermediate driver will probably notice he's off the apex at or just before the apex. At that point, some corrections my help keep him on the pavement.
- An experience driver will notice he's off the line just after the turn in point. At that point, the experienced driver has the opportunity to use the many tools in his toolbox to correct and still makes something out of the corner.
- As for Schumi - per Bently's comments, he knows millimeters after turn in that he's off - and starts correcting much, much sooner than most. It looks like he's hitting the line perfectly every time - because he knows EARLY what to do to get the car there.

That is the key difference between expert and beginner drivers and corners - the experts know sooner they are off, and start correcting earlier.

I am discovering that this driving stuff is much more analog than digital. Braking, throttle inputs are to be analog (smooth inputs) and not digital (on/off switch). Similarly, you can't just 'set the car' into a corner and get a perfect line - there are minute corrections that you must do in the corners - EVERY corner to be able to hit the line - after all, our cars are analog as well - the conditions are constantly changing a little - tires heat up, brakes fade, the car weighs less (via fuel consumption). And most importantly, the driver is analog as well - he's not either "On" or "Off" he's constantly in an area between the two - hopefully more 'On' than 'Off.'

-Zoltan.

PS:
Did someone say G Sum? G Sum makes Homer dizzy...

analogmike

VERY COOL!!! That is why I have problems going from the '73 to the '04 car.

With the '73, I always drove the front tires, when the outside front was planted I could do whatever I needed to do and the car would let me. And it may be the fast way to drive that car as it keeps the rear planted well. I worked hard to get that front tire planted, I would tell people I was driving the front tires although I never heard that phrase from anyone else.

With the cup car, I can't get the car balanced on that front tire as it's a real race car and set up for pro drivers who drive the rear tires. Sometimes I am able to do that powering out of a turn like after the esses at Road Atlanta but not often.

I have to start thinking of driving the rear tires more... thanks for pointing that out.

Professor Helmüt Tester

Amen, brother. The kernel of genius...so pay attention, kiddies.