Originally Posted by simsgw

That preparation is about what I guessed from your questions or I wouldn't have bothered with a detailed answer. As many of us will confirm, a few days with Skip Barber in Formula Fords or at Porsche's performance driving school are worth more than a year of DE days.

The brief answer to your question is yes. Less briefly, to justify that:

We need a brief diversion into terminology. To an R&D engineer, the pattern of the vehicle's thrust is more important than the edges of the road, so I tend to think of the apex as being the inflection point in that curve, the point where you transition from braking *** cornering to acceleration *** cornering. And if you have a cornering sequence that requires the tires' grip be devoted to maximum cornering, with neither braking nor acceleration (except from drag), than the apex would lie at the point where acceleration began again. If it was noticeable at all, then a second apex would precede that for analysis purposes. That would be the point where braking had to be abandoned to permit that maximum cornering grip. (Usually the point where a good driver completely releases brake pressure isn't noticeable at all. In geek terms, it doesn't cause an inflection.)

All very theoretical and not what my driver's intuition calls an apex of course. We think of our apex as the closest approach to the inside of the corner, which sometimes includes putting the inside wheels off the pavement. The theoretical approach is needed for analysis, if only because we often race on courses that compel an apex that may be a hundred feet from the edge of the pavement. Converted airport tracks are notorious for this. If I must achieve 200 degrees change in direction in a couple of hundred yards of WWII pavement, does the lack of an edge mean I had no apex? Of course not. And novices at such tracks are taught to pick up on the past rubber deposits and think of those as the track surface, planning their apex by the closest approach to the edge of that pattern of rubber on the much much wider pavement. For DE days, they add pylons of course to make these things more visible.

Okay, with that pettifogging out of the way, let's stick with a driver's intuitive meaning of apex. That's the one you'll see in books by non-engineers so we better use it. That means the answer is yes. Many corner complexes require acceleration to begin before reaching the inside edge of the track, before that intuitive apex. The reason in racing is that speed at different parts of the track has more effect on the lap time than others. If the section following the upcoming corner is one we want to take at the highest speed possible, then we take a "late apex" allowing us to accelerate before the apex and leave the corner at a higher speed. The apex comes after the "thrust inflection" of us engineers, but it also is positioned further down track because we did so much of the cornering before reaching it to allow early acceleration. That makes it 'late' even to drivers' intuition. I believe it was Graham Hill who first brought this to public notice back in the seventies. (By winning this way of course.)

The converse is also appropriate although it worries us when teaching novices. An early apex is one where the inside edge is reached before you finish trail braking, or at least before you can begin acceleration. We need an early apex when the preceding track segment, like a long straight perhaps, is more important to the lap time than the segment following. For the best lap time we need to carry the speed as deep into that corner as possible. We also use this to pass other cars, but that really isn't covered in early training. The early apex means a very delayed start of braking and that means using as much of the corner as possible to scrub off the rest of that oh-so-desirable speed that now is keeping us from getting the car turned and accelerated into the following segment. It may be less important than the preceding straight, but we do want to traverse it from the track surface instead of hanging on a tree limb or spinning off into the desert (where I live now, we don't keep trees. At least not around race tracks.). And when racing, if you use that late braking to pass, then you don't want the other driver to do an "over and under" move by using a late apex and early acceleration to blow past your desperately cornering car. (But I never mentioned that. You never read that here. This isn't race training by e-mail. Honest.)

On public roads, I don't even consider an early apex. And they are not taught to novices at DE days either. In fact, I think the PCA doctrine for instructors is not to teach trail braking either. It's that same issue of learning first to blend acceleration and cornering instead of learning the more difficult skills. You need to have building blocks in learning. Even when we know the theoretic basis for more advanced techniques, we need to let our motor skills progress by the one-step-at-a-time approach. Besides... if you get a late apex wrong, you simply blow your lap time. Backing off on acceleration saves you from departing the track for example. But if you blow an early apex, you're already committed and likely to need a vacuum cleaner to get the sand out of places you never knew it could reach. You will go faster if you get it right, but you must get it right or spend time communing with desert tortoises. Or a tree. Including "must do it right" segments isn't the way you teach a subject like driving or flying. Uses up students for one thing.

So the overall answer is yes, once you learn to hit your apex, which isn't a trivial skill, then you learn how to start acceleration beforehand or finish your braking afterward. Either skill should come later, but in fact the safety benefits of a late apex usually mean that that technique is the way people are taught "the racing line" even when real racers might be using an early apex at some of the same corners.

For now, just learn to hit the apex wherever an instructor tells you it should be. Learning to put the tires over particular spots on demand is itself a fundamental skill you want to learn. Later you can learn to pick the apex yourself for the best lap time.

Gary

Originally Posted by IAA-C63

BTW, are you an engineer? I am, and I gathered from your post that you might be too.

Originally Posted by Rodolfo

Heel and toe is not really necesary with modern syncronized transmissions.

It was a most, maybe 30 years ago, but now, if you match your car speed with your engine speed, gears almost can go in without using the clutch.


Try going full speed to fourth or fifth, then brake really hard and downshift to fourth, third and second. Gears will go in with no problem.

Most of the downshifting will go down before you enter the corner, and you will be controlling the throttle before you get to the middle of the corner.

Originally Posted by buckwheat986

Are you referring to on the street?

On the track it is certainly necessary. At least in my experience.

Originally Posted by Rodolfo

It was a most, maybe 30 years ago, but now, if you match your car speed with your engine speed, gears almost can go in without using the clutch.

Try going full speed to fourth or fifth, then brake really hard and downshift to fourth, third and second. Gears will go in with no problem.

Originally Posted by Rodolfo

Yes, I ment on the track, I only use it on the street if I am laisy and want to shift form 4th to 2nd, On the track I will got 4th, 3th, 2nd, and no rev matching will be necesary.

Not meaning to start an argument, but when do you use it on the track?

Maybe we could share points of views, and improve our driving teknics?

Originally Posted by Rodolfo

Next time you are on track, or on the street, go full throttle to 5th, then brake hard and start downshifting the gears.

ALL THE TIME YOU CONTINUE BRAKING

Clutch, then put 4th, then de-clutch
THEN
Clutch, then put 3th, then de-clutch
then
clutch, then put 2th, then de-clutch

STOP BRACKING

gears will go down rather smoothly, and you are ready to turn into the corner and start giving thorttle.

Just try it, today at the street, or this weekend on the track.

If you think that damages the transmission, you should give more credit to your 100k car.

But as I say, first try it, and then come back and post your opinions.

Originally Posted by Rodolfo

Next time you are on track, or on the street, go full throttle to 5th, then brake hard and start downshifting the gears.

ALL THE TIME YOU CONTINUE BRAKING

Clutch, then put 4th, then de-clutch
THEN
Clutch, then put 3th, then de-clutch
then
clutch, then put 2th, then de-clutch

STOP BRACKING

gears will go down rather smoothly, and you are ready to turn into the corner and start giving thorttle.

Just try it, today at the street, or this weekend on the track.

If you think that damages the transmission, you should give more credit to your 100k car.

But as I say, first try it, and then come back and post your opinions.

Originally Posted by utkinpol

as of syncros allowing gear to get in - it is never a problem, problem is to complete all transitions smooth without upsetting car`s balance.

Originally Posted by IAA-C63

1. At what rpm do you typically shift from 1st to 2nd? I find 1st to be kind of annoying because you have to shift fairly soon to 2nd, whereas the car needs decent speed to handle 2nd without bogging, so getting the car off the line fast is a bit of chore. But maybe I'll get much better at it with practice (which is certainly my goal).

Originally Posted by Rodolfo

Of course if you are mid corner, and you want to go from 4th to 2nd, then you should heel and toe a bit, but this just aplies if you want to do something like that, from 4th to 2nd, or from 5th to 3rd, and in this last case not as much.