bobt993

Patrick, for comparison the distance factor has been locked so" under the curve data" can be compared. I was comparing and helping another driver with his laptimes. He is looking for another second in a 993 so displaying the blue car ahead of him does nothing for his game plan. Knowing where he is slower and by how much does. Making up time in entry/mid-corner can be worth a couple of tenths per corner. On an 11 turn track this adds up to a couple of seconds. Late braking seldom is the key as it causes entry problems unless you have that sorted already. If your going to analyze data use distance and speed for the simple reasons:

1. You know where you are on the track and where to make changes.
2. You have an idea of what speed differential you are looking at while entering, apexing and exiting the corner. You can spin your speedo to the appropriate position and mark the target on gauge with a small piece of white tape. Start working up to it by taking less speed down the approaching straight even getting into the proper gear early. No brake drills also help with this process. Instead of doing 130mph for the entire straight slow it down to say 80mph if your target entry is 60 in the turn. This slows down the transition managements and allows you to focus on corner speed.

FWD car is a very different animal. A buddy of mine has switched from FWD to a Porsche and it took him a little time to get his racecraft adjusted, but now he is flying. Rolling is the final transition from trailing and you may drift slightly before the apex, but it should feel just on the edge after apexing as steering is ready to open up. Getting on the throttle is the easy part. When I was instructed by a pro coach he explained that if you hit the apex every time your throwing away entry speed. It should be that hard to get to the apex.

333pg333

Interesting points Bob. So you're really emphasising corner speed over braking in this case.

I was going to work on something along those lines next week at a mid week trackday. I liked the idea of slowing down early on the main straight and working up towards trying to get through the fastest corner on the track flat out....(there's that phrase again). Then I wanted to just start getting deeper before the corner to carry more speed. Eventually getting both down to my current maximums. Either that or spinning into oblivion...
Thanks for the graph and explanation. Appreciate it.

Earlierapex

lateral acceleration and friction (tires and wind) slow a car dramatically, so you have to apply a fair amount of throttle to maintain a consistent speed through a turn.

After the apex, you are, generally, unwinding steering angle which decreases lateral acceleration and increases tire grip available for straight-line acceleration (or more technically higher speed lateral acceleration).

Said another way, lateral acceleration is a function of two things 1) radius (how tight is the corner) and 2) speed. Taking a corner in a car, you don't actually follow the exact degree of curvature of the turn. With a late apex, you turn the car more early in the turn to "straighten out" the back part of the turn to give yourself more room to get on the throttle earlier and accelerate longer on the following straight.

The "throttle balance" described above is simply adding throttle as the "radius" lateral acceleration decreases after the apex so that the speed part of the lateral acceleration can be increased.

Your car will experience peak lateral acceleration between the point of greatest rotation (unless you have 700hp) and the apex (think of "fighting" the car to the apex). The point of greatest rotation occurs earlier in the turn for a later apex and generates more lateral acceleration earlier. So a later apex requires slower corner entry speed because you have to use tire grip to rotate the car more earlier in the turn. Said another way, the later the apex the sharper the actual curvature the car takes through the turn, but the more time and room you have to correct a mistake because the "sharpness" of the turn occurs early.

To increase corner entry speed, you have to take an earlier late apex which results in later, and less, car rotation. Move your point of rotation (max steering angle) closer to the apex.

Keep in mind, you are now going faster and rotating the car later, so the margin for error is much smaller.

The best way to do this in a FWD car is to sell it and buy a RWD car.

M758

Corner speed is MUCH more important than braking. Corner speed = lap times. Braking just one method getting to the right corner speed. Of course the key to high corner speeds is a balanced chassis. This means you need to have the chasssis balanced for that corner speed and all braking needs achive the proper corner speed with the car balanced properly. It is very easy to go into corner so deep that by the time you get to the rigth corner speed the chassis is loaded such that you cannot turn. Bad news. This is why when you are looking for ultimate corner speed you brake sooner and softer. This allows the chassis to be more balanced at turn in and corner entry. Only then can you work on moving braking point deeper, but maintian the proper chassis balanced needed to make the corner.

333pg333

Yes Joe, I guess I see them being pretty interlinked. Listening to some responses in here and another thread makes me more secure about what I'm doing because it seems more like what I'm feeling in the car rather than some of the confusion from reading some books. Not that there isn't something to be gained from all these influences and texts...but it does become a little mind boggling when you go from a purely instinctive driver (which most of us probably are) to a more methodical one. I see data logging as crucial to make advancements now.

https://rennlist.com/forums/racing-a...ley-et-al.html

M758

The actually drive on track needs to be instinctual to be effective. This menas you just do it. Thinking about what to do costs you time and is just not possible in racing since you need to concentrate on racing the the rather purely making the corner.

That does not mean you don't use a logic and methodical approach to testing and learning. If you are learing a new skill or trying to eliminate bad habits you have to think about it.

jrgordonsenior

I think I mentioned this in previously, but if you're going to go out and practice threshold braking stiffen up your front sway bar a notch or two. This allows you greater control over the rear of the car and was instrumental in building up my confidence. I spun the car repeatedly trying to get the transition to throttle down right until we went full stiff up front. Then I had more control and could focus on the actual braking and when/how to transition to throttle.

I had a moment at Laguna last weekend entering T10 when it started to get away from me as I lifted/transitioned off the brakes. All that practice gave me the faith to continue to throttle and not brake or over correct the wheel. Worked out just fine thank you, it really is a learned art form....

333pg333

Something you said before JR struck a chord with me. When you said "It's ok to coast". In my mind (not always reliable terrain) the idea of all this "you must either be 100% full on brake or throttle" syndrome just doesn't 'seem' right to me. I just have images of the car being so unbalanced. There are times when I'm sort of just feeding the brakes on initially before applying harder pressure-then releasing/back onto throttle. I think this is what most amateurs do and I've also noticed with pretty much all the pros I've been with that they have a harder initial brake cadence or moment in most instances. So I guess it's about finding that 'balance' as per usual that nets the quickest times.

Cheyenne

Thanks for the feedback.

Between doing some reading here, and reading a driving book I've been playing with my technique, and now realize why I don't use more corner entry speed: I'm already waaaaay past where I should be on the street. It was fun, but removed my margin for error.

I'm going to get a Miata with all season tires to keep training on the street, with late apexes for plenty of margin, and finally get my butt to the track to play with those speeds that just seem to harsh for the street.

FWD has been good to me, I can rotate to any angle I need in almost any situation, but I'm long overdue to learn RWD technique. Got to drive a 'vette once, but they wouldn't let me turn off the stability control and that thing pulls the plug on the power for a loooong time if you get just a bit sideways. I can't afford a toy like that so can anyone tell me if any RWD, but with poor traction, can be used to learn, or is the combo of big tires and big power a much different animal that small tires and using a lot of momentum? If so, I'm just screwed...Here's hoping my first DE is in the rain, regardless of the car.