JCP911S

Greg F.... I define "apex" as that point where the car is clipping the inside of the track. I agree that every turn has a "geometric apex" that does not change.

Every corner has an optimum line for a given car and driver that minimizes lap times. This is really a personal thing. The apex as I define it above is simply an aiming point to tell you whether you are on your optimum line or not. I would say every car/driver combo has a slightly different optimimum line.

There is nothing magic about an apex. It is really no more significant than any other reference point other than giving you an indication of whether you nailed the turn or not... which is an important piece of info. But "hitting the apex" won't help you if you go off the track anyway. I mostly use it to determine when I can flat-foot the gas.

a4944

It also depends on the approach to the turn. If you are coming down a long straight then you can brake into the turn further with an earlier apex, carry your speed longer down the straight. You have to consider both the approach to the turn and the exit from the turn.

It may also depend on gearing. You may be able to stay in a higher gear and slam the car into the turn and scrub some speed off while staying more on the throttle. I used to do this with the Audi. The pedals are terrible for heel and toe (at least for me). I would stay in a higher gear and compensate by slamming the car into the turn and using throttle to control the drift and rotation. I'm experimenting with this approach with the 944 Turbo since it does not have limited slip and I have trouble getting power down in some turns when I down shift. It also takes a small amount of time to shift and you can save that time by staying in a higher gear. Note that this is for an understeering or neutral car. I'm not sure if it's any faster yet, just something I'm experimenting with.

One of my favorite quotes from an instructor when I was an advanced student ...
"Slow in fast out is good, but fast in fast out is better."

Mark

JCP911S

To quote Hans Stuck (I believe) "In slow- out fast... In fast- out dead"

Seriously, this depends on the car and the turn. Certaily a 911 is much safer with a slow-in/fast-out style. A more neutral car is more tolerant of mid turn corrections..

Also this is apprpriate when exit speed is a priority... such as entering a straight. Finally, you don't want to carry so much entry speed that you are struggling for control through the turn... IMHO it is always best to keep the car as tidy as possible.

mitch236

Why not? As long as you make it to the apex and don't have to scrub off speed to stay on line, go as fast as you can! Remember, if it feels like your car is on rails, you're not going fast enough (I forgot who said that)

JCP911S

mitch236... there is a fine line here between drifting the car a bit and scrubbing off speed. I was talking about trying to carry so much speed that you get the car out of shape.

In theory the tires have maximum grip just at that point where they start to slide just a bit... thats where you want to be... any more slip angle and you are slower.... if I ever can actually do that, I'll let you know if it works.

JackOlsen

A simple way for lass-experienced drivers to see the difference between fast-enough and too-fast entry speeds is to look at the point they're able to get back on the gas. Earlier is better, and exit speed is almost always more important than entrance speed, at this experience level.

The point a lot of these posts miss is the difference in skill levels and goals for drivers at different points along the learning curve. I remember that ColorChange thought it was a good idea to work on trail-braking before he had much of a clue about the importance of the driving line. He's probably revised his opinions on this since then, but it illustrates my point. Newcomers to track driving need to put together a basic skill set and work up from there. First you work on the driving line. Then you work on exit speed. Finally, you work on entrance speed. Beginners typically try to re-arrange this sequence, and it usually slows their progress as drivers, in my opinion.

Rich Sandor

That's actually a really good point. I found my driving a got lot smoother (and faster) when I prioritised my goals in that order.

JCP911S

J.O. Great advice.... wish I'd thought of it. You could take the same approach with apexes... start late and move it earlier and earlier until you go off the track, and then turn it back a click later...babbada bing baabada boom!

JackOlsen

I missed the typo. Obviously, a driver's experience with the ladies is not really significant when it comes to cornering.

TD in DC

Who says? I thought the whole point is to be smooth and know the lines!

On the other hand, I am not so sure about this slow in, fast out business.

ColorChange

TD

LOL

Geo

Excellent post.

Back when I started karting I used to dive into corners as hard and deep as I could and thought I was setting the world on fire (for the equipment I had). Then I smoothed things out and started braking a bit earlier and damned if I didn't get faster. Eventually I braked deeper into some of those corners again, but usually not as deep and hard and with a whole new appreciation of what the effect of getting it wrong was on the back half of the corner.

Also, at the SE-R Club DE a couple of weeks ago, the single biggest error I saw, including from some experienced track pilots was going in too deep. You may be able to keep it on the track to the clipping point or whatever, but invariably they were slower out of the corners.

One last point... On the "Drive to Win" video of about 20 years ago with Mario Andretti and Gilbert Pendault the comment was made that the most common mistake that is made is driving too fast into slow corners and too slow into fast corners. I've thought about that for all these years and continue to think about that and for sure evaluate that as I go to a new track. I think generally it is VERY true.

Geo

That is usually rather deceptive. Of course everything is relative. What is too deep for me isn't for say Prost, but it's really easy to go too deep to get maximum exit. Too often your front tires are still scrubbing speed as you try to get them to turn.

Geo

Stirling Moss.

"I'd rather go in slow and come out fast than go in fast and come out dead."

Larry Herman

Time to add a little more to the mix, seeing as this has morphed into a slow in - fast out theme. Along with having the proper car atitude, there is a specific slowest point in every turn. Coming off the straight, you are braking down to that point. Once you pass that point, you are accelerating away from it. For me, that point is usually early in the turn, somewhere in the first third. I am braking down to that point, then I am at full throttle accelerating past the apex, and out of the turn. That point, the transition point, is where I go from the brakes to the gas.

I find that I drive most turns this way, with the transition point being very early in an increasing radius sweeper, and quite deep, sometimes almost in the middle of a decreasing radius turn. Regardless, I try and take a line that lets me brake down to this point and then transition to WOT as immediately as possible. In double apex turns, such as Lime Rock's Big Bend, I treat the part between the two apexes as a very short straight, and yes, I am at wide open throttle between them, even if it is only for a second or two. What are you doing?