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-   -   ABS at the track (https://www.corvetteforum.com/forums/c7-tech-performance/4053709-abs-at-the-track.html)

desmophile 10-12-2017 04:55 PM

ABS at the track
 
Do those of you that track a C7 intentionally use ABS in any specific situation or do you try to go right up to it?

Would you do so only in braking in a straight line or begin turn in when it was still active?

My track experience is about 1200 miles in our '17Z06/Spring Mt. I now have one track session where I have used PTM/press the accelerator to the floor at apex, and now have faith that it works (dry PTM only so far), and it seems like it is kinda cheating-makes me look better than I know I am:D. Using the ABS going into corners/starting a turn, seems a little like the opposite of this-exiting a turn and letting the electronics keep the car going where you are pointing it by keeping the tires from spinning.

So I just thought about asking those with much greater experience if you choose to use the ABS going into a corner, maybe begin turn in while it is still active, or use it like I have as a back up? Seems to me the car brakes a little harder just before the ABS kicks in.


Here to learn. thanks, paul

MitchAlsup 10-12-2017 05:40 PM

I find using the brakes hard enough to "induce ABS stuttering" upsets the fine line one can keep the car on.

rrsperry 10-12-2017 09:41 PM

Be a man, pull the fuse.... you'll be a much better driver.

rb185afm 10-13-2017 02:34 PM

ABS is not good on track. If engaged while your rotors are glowing red, warped rotors will follow.

Bill Dearborn 10-13-2017 07:00 PM

I haven't used ABS on track except in an emergency. With Slicks I can slow the car very fast and hard without locking up a wheel. I have used ABS on track in emergencies or dangerous situations. One time at the Glen I was following another car out of the Carousel turn into the Chute. There is a little crest as the transition is made and you can't see anything on the track surface. The first I realized there was a problem was when the car ahead of me started slowing and going sideways. Then I saw the oil on the track. I was in the oil in a blink and was fast closing on the car ahead. I touched the brakes and the ABS kicked in and let me coax the right side tires out of the oil and get control of the car. The Corvette in front of the car in front of me dumped its power steering fluid right in the driving line.

Bill

Dane@LGmotorsports 10-14-2017 04:14 PM


Originally Posted by Bill Dearborn (Post 1595760326)
I haven't used ABS on track except in an emergency. With Slicks I can slow the car very fast and hard without locking up a wheel. I have used ABS on track in emergencies or dangerous situations. One time at the Glen I was following another car out of the Carousel turn into the Chute. There is a little crest as the transition is made and you can't see anything on the track surface. The first I realized there was a problem was when the car ahead of me started slowing and going sideways. Then I saw the oil on the track. I was in the oil in a blink and was fast closing on the car ahead. I touched the brakes and the ABS kicked in and let me coax the right side tires out of the oil and get control of the car. The Corvette in front of the car in front of me dumped its power steering fluid right in the driving line.

Bill

^ Driver

Paul- ABS pulsates the brakes allowing ability to steer but ultimately slows deceleration. Total lockup makes the car similar to a globe, turning the steering wheel isn't really affecting direction of the vehicle itself just rotating the contact patch on an axis while momentum takes its course. The most effective way to slow a car is threshold braking, pressure to the very edge/line where lockup or abs engagement would occur. You have two limiting factors in braking, well three if you count yourself. The one most talked about is braking force (caliper/rotor/composition/heat/fluid), the other is tires, you can have all the force in the world to slow the wheel but it does nothing if the tires aren't gripping the surface. Bills reference to running slicks is solid advice. Slicks allow the maximum contact area along with a soft compound so that the highest possible amount of braking pressure/work is translated to the ground and in turn the car slows much quicker.

spearfish25 10-14-2017 08:24 PM

As these guys have said, ABS should not be a habit. It's a safety if needed. I've found that hot Cup2s have so much grip that I'm sometimes pushing my knees against the dash during braking. Happens every time I brake for the turn 7 hairpin at Sebring despite locking my belt snuggly before the session. I feel like I"m going through the windshield, push my knees against the dash and wish I had a full harness. Every time. But no ABS activation.

mcoomer 10-15-2017 09:10 AM

ABS shouldn't be a habit anywhere, street or track. It is meant to help you not lose control of the vehicle when your brain tells your right foot that you're about to die. If you're getting into the ABS regularly you're doing something wrong. Moreover, as Spearfish noted, I've found it hard to get the system to kick in. The hardest I've ever stood on the brakes was during the CCB rotor break in and as hard as I was standing on the pedal it never came on.

Mike

Poor-sha 10-15-2017 02:29 PM

The ABS is working on this car all the time if you're braking hard, but it's usually in the form of it dynamically adjusting the brake bias so you might not feel it. Check out this chart of the ABS Active and Speed channels from a lap of VIR.


https://cimg6.ibsrv.net/gimg/www.cor...7b80a846dd.jpg

mcoomer 10-15-2017 05:26 PM


Originally Posted by Poor-sha (Post 1595769610)
The ABS is working on this car all the time if you're braking hard, but it's usually in the form of it dynamically adjusting the brake bias so you might not feel it. Check out this chart of the ABS Active and Speed channels from a lap of VIR.

Poor-sha, please help me understand your chart and your statement. I wasn't aware the ABS was capable of adjusting brake bias. I assumed it was simply waiting for its sensors to tell it you were in need of assistance. Interesting to hear that it's lurking and working all the time. Your statement implies that it's modulating the pressure to the calipers all the time. Am I understanding this correctly?

Thanks,
Mike

Poor-sha 10-15-2017 09:10 PM

Correct, I believe the C6 had this as well but it's dynamic brake bias. It adjusts rear brake pressure based on steering input and other factors. I will say that it was far more noticeable on my 2015 Z06 than my 2017 Z06.

Racingswh 10-15-2017 10:25 PM

I use abs probably imperceptibly every single lap but most noticeably into turn 7? at NJMP Thunderbolt. I know that when I am rolling through 6 and come up on 7 which is about a 65 mph corner I stand on the brakes hard and relieve pressure as I enter.

Right at the moment I stand on them I feel a pulse or two no matter which car I am driving. Must just be the lack of grip right there on that pavement for just a moment.

I can not think of anywhere else I noticeably use them even in threshold brake zones.

I can say though I have seen where the fastest guys lean HEAVILY on their ABS and watched on two separate occasions with two different drivers during ABS failures flat spot all four tires in an instant. They were using ABS to the fullest extent possible.

BrunoTheMellow 10-16-2017 05:21 PM

Hitting abs at the track means you're braking the car to the limits of the tires. I've learned that you should be just a hair below abs levels but its ok to hit it once or twice a lap.

Now your other comment that you;re going WOT mid corner and letting PTM DRY pull you out, you are losing a ton of time doing this. First of all, PTM DRY uses SPORT suspension, so you're not fulling utilizing the capabilities of the suspension. Second, DRY is fairly aggressive with traction and stability control. Swap to SPORT 1, most drive on this mode. I run sport 2 when tires/brakes are at perfect operation and want to let the back end out every now and then to eliminate bogging down. I rarely ever feel the system kick in so I don't find RACE useful.

desmophile 10-19-2017 08:21 PM

using ABS on the track
 

Originally Posted by BrunoTheMellow (Post 1595777181)
Hitting abs at the track means you're braking the car to the limits of the tires. I've learned that you should be just a hair below abs levels but its ok to hit it once or twice a lap.

Now your other comment that you;re going WOT mid corner and letting PTM DRY pull you out, you are losing a ton of time doing this. First of all, PTM DRY uses SPORT suspension, so you're not fulling utilizing the capabilities of the suspension. Second, DRY is fairly aggressive with traction and stability control. Swap to SPORT 1, most drive on this mode. I run sport 2 when tires/brakes are at perfect operation and want to let the back end out every now and then to eliminate bogging down. I rarely ever feel the system kick in so I don't find RACE useful.

Thanks for all you guys replys!!
Since I want to learn to drive, I am good with the plan to pursue the limits of the car/mine and have the ABS as back up for unexpected events such as oil/debris/other traffic issues.

It has seemed to me that deceleration is harder if you don't get into the ABS so that seems like the edge to aim for.

thanks, paul

village idiot 10-21-2017 10:45 AM

I go straight to Sport 2 and sometimes even race.

I rarely get ABS engaged, but if you do, it's not a big deal. Do the same thing you'd do if you lock up the brakes- take some pressure off the brake pedal.

I like ABS because I don't have to buy new tires when I flat spot them. Also, it's a $70k car. I'll take a little bit of time off for a lot of security against spinning into a wall.


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