ColorChange

M758
I agree completely. What you guys really need to do is get a data acquisitions system installed so you know if you are on the friction circle or not. It is an invaluable tool if you are technically oriented.

turbite

Out of curiosity, How would the data acquisition know that?
I'm curious about what data your talking about and how you interpret it.

ColorChange

Dirk, a g-g plot shows how you transition from braking to turning to acceleration through a turn. Good systems are not expensive, under $2k. I use an Aimsport system.

http://www.aimsports.com/index.html

The data is amazing but you do need to be fairly technical to interpret it (I'm an engineer). For example, you can plot steering angle as a function of lateral g's and see if you are understeering or oversteering in particular corners, ...

DrJupeman

Z-man, I recommend simply braking less.

(Sorry, I thought a little flavor from the GTC board might make you smile here, too.)

- Jupe

turbite

Tim,

I guess what I don't understand is how the data acquisition knows where 100% is.
If I'm turning at .5 g's and slowing at .5 g's, how do you know that this is x% of the maximum.

I could see it would be useful in the very least to show how smooth this transition is.

DrJupeman

Dirk, the data acquisition doesn't know where 100% is, but you can decipher where YOUR 100% is from all the data. In other words if you're pulling 1.2 g's in one corner, and you're not in another, you know you should be able to go faster (pull more g's) there.

The comment earlier about using that data in trail braking is that you should be at max adhesion at every point through the turn. Sometimes trail braking is the way to get you to do this.

I do not do much trail braking myself, but with my new-to-me car with 100% locking rear under deceleration, I plan on learning quickly!

Z-man

Thank you sir, may I have another!

-Z.

Ken

Z-man, here's an interesting article about braking I read the other day. The most important thing I got out of it was about the "backwards braking". I don't know if you've read this before, but I just found it.

http://www.homestead.com/redlinerenn...13Braking.html

Jerry

The quickest lap times are achieved by taking most, but not all, turns in the slow in (a relative term) and fast out approach.

ColorChange

Jerry, that is wrong. The quickest lap times are achieved by staying on the friction circle as much as your car allows, and by choosing the proper line. The best race car driver does two things (lets skip traffic for know, or mechanical issues), selects the optimal line, and maximizes g forces. In your specific example, enter fast, apex fast, exit fast. Now, should beginning drivers enter slower and exit faster, absolutely, but not top racers.

RedlineMan

Hey All;

great stuff as always guys!!!! A bit late to the party here. Trying like HE!! to get my fuel cell done!!

Trail Brake - Used in corners where the entrance is fast but the apex can be difficult to negotiate (decreasing radius, for instance). Helps rotate the car for early acceleration. Braking only in the straight would be slow in such a turn. Is the progenitor of "outbraking" and related to "oh $hit I've entered too fast" braking, but SHOULD NOT be confused with either.

Big Bend is a perfect example. You brake a bit going in to settle the nose and take off a little speed. Then you release the brakes and scrub speed going past the first "apex." Then you brake harder again to help rotate the car before the turn in point for the exit.
-----------------------------------
Braking late (or "charging" the turn) makes drivers slow because they do not have the time or experience to multi-task and blend the speed reduction portion of the recipe with the turning portion. They are still separating the two by the compartmentalization of inexperience instead of flowing them together. This is a function of thought and seat time! Further, trepidation caused by their late braking point uses up concentration reserves needed for turning.

See this article in my Pilot Emeritus Series;
http://redlinerennsport.homestead.co...inessCone.html

The no brake exercise is OUTSTANDING for taking the emphasis off of "one aspect-then another-then another" turning rituals. It FORCES you to blend them all together smoothly, and perhaps subconsciously teaches you that this blending of braking and turning should be used ALL the time. "That is how the car should feel in a turn. Now shoot for the same feeling at normal speeds!"

Given the Z-man example turn (one shift, classic 90 turn). I use a real hybrid approach. I brake somewhat earlier than many people, hardly ever to threshold (unless I've blown it!). At the appropriate point I pull my H&T downshift. Then once I have completed 80-90% braking I switch feet and transition to left foot brake for any additional straight-line or trail braking necessary. My right foot adds throttle somewhere in the mix and acceleration begins simultaneously while braking ends. Ultimate recreation of no-brake cornering smoothness. Guess I should get one of those g-meter doohickeys to see for sure, eh?

The cornering sequence you read about above is offered by a highly trained amateur. Don't try this at home.

forklift

I have a question related to this thread. Coming down the straight at my local track at about 130 down to a 50 mph turn, I apply maximum pressure (a hard squeeze, not a slam) and have yet to activate the a.b.s. I have tried panick stops from many different speeds and still don't activate the a.b.s. At least I can't feel any vibration through the pedal, and the tires never lock up.

A buddy of mine just bought a 993 w/ shot tires and we could activate the a.b.s. easily until he replaced the tires.

What would it take to activate my a.b.s. on my 964? I have Pagid Oranges and the car stops very quickly.

RedlineMan

Hey Fork;

Trail brake and find a bump!
----------------------------------------------------
Seriously, one of the main drawbacks to trail braking is finding bumps mid turn. Really gets dicey then. I get wheel lock in quite a few places at various tracks because of this.

I had an off in the left hander at Lime Rock last year caused partially by this. I missed my brake point (distracted... on someones bumper!!). There's a patch right in the middle of the track in the transition from left side trackout to the right side turn in, and when I broke I hit that patch/bump, locked for a second, and then decided to drive off instead of spin!

Therefore it is reasonable to assume that waiting till the last minute to brake does not leave a lot of margin for error!! Sure... we can all do it.. but what's your point?!?!?

mitch236

Wow, I've missed alot. There is a wealth of good advice here. As for the no brakes to find the speed a given corner can handle, that is a little off. No brake cornering is great for learning smoothness and car control, but one can go faster through the corner using proper braking techniques than can be done without brakes.

I think it was Mario Andretti who said, "I'm amazed at how many drivers think that brakes are for slowing the car"

Brian P

True, but the context is for someone who thinks they may be overbraking. Generally an overbraker (speaking from experience) has the car so far out of balance that they limit the speed that they are capable of through a corner. By going to a "no brake" technique, they can get the car well balanced entering the corner and then they can get a much better idea of the true speed potential. After that, then they can work on integrating braking technique.

I've found in other sports that sometimes a person just needs to do something very different from what they are currently doing to break a bad habit. I.e., an overbraker should go to "no braking" to rid themselves of the habit of late braking. This forces them to pay much closer attention to all phases of the corner as they are doing something completely new. After they have broken the bad habit, they can then begin working on the correct way of doing things.