ABS and Brakes lock up??

[NSXDreamer2]

I got very confused that how our ABS worked (on stock size rotors and stock caliper). When on high speed (say calling for full braking around 140 to 65-80ish, it stopped perfectly, no ABS feedback, no tire squeaking)

Now for lower speed, (well it's a bumpier session), I would expect the ABS will engage but all I hear is lock up and tire squeak... There's a time I missed the braking point into a slight banked slow corner and really just stepping on the brakes and clutch (which is around 80-30 ,or 25ish) ABS kicking in but no tire sqreeching...

It's just not quite make sense to me...

 

[nsxtasy]

I got very confused that how our ABS worked (on stock size rotors and stock caliper). When on high speed (say calling for full braking around 140 to 65-80ish, it stopped perfectly, no ABS feedback, no tire squeaking)

My guess, based on your description, is that you did NOT engage the ABS on these stops. The ABS generates a noticeable pulsing in the brake pedal, and you will hear the ABS pump engage. The fact that these symptoms were not present indicates that you did not engage the ABS.

This is not surprising; the NSX brakes are very, very good, and the car can feel like it is stopping amazingly even without engaging the ABS. In fact, on a test ride once, I tried engaging the ABS and had to try numerous times before I could get it to engage - just because I didn't realize just how much pedal pressure was necessary.

Now for lower speed, (well it's a bumpier session), I would expect the ABS will engage but all I hear is lock up and tire squeak... There's a time I missed the braking point into a slight banked slow corner and really just stepping on the brakes and clutch (which is around 80-30 ,or 25ish) ABS kicking in but no tire sqreeching...

It's just not quite make sense to me...

I'm not sure what you're describing here. First you say that the brakes lock up and the tires squeal - which both imply that the ABS is not working (and perhaps there is a problem with it) - and then you say that the ABS is kicking in, which implies that the ABS is working fine.

In any case, keep in mind that the objective in track driving is to execute "threshold braking", meaning braking just on the threshold of locking up the wheels, but not actually locking them up. With proper threshold braking, you will never engage the ABS.

 

[NSXDreamer2]

I'm confusing Ken big time again

It's actually happened in two different corners... I pointed out the later just to make sure you understand that my ABS was working fine, (w/ a lot of Seattle rush hour driving, you know I mean?)

I'm understanding the tire squeak is not desirable on track... At the same corner I squeal tires, I actually did it everytime, and I couldn't brake without doing that, unless I really want to brake very deep into corner and risk carrying too much momentum into the corner. One thing I know for sure is that there's a dip there and it's an infamous Porsche dip ( the instructor told us that Porsche car had always lock up their tires when they do that.) Exactly what I experienced.

I guess this is my real question: Is the ABS designed to "anti - Locked brakes" ?? IF so, then why would my tires squealed??

 

[nsxtasy]

Now it sounds like you are saying that your tires are squealing IN the turn, not in the braking (which should be completed PRIOR TO the turn).

Tires can squeal going through a turn, and that has nothing to do with the ABS.

I don't know if that helps...

 

[NSXDreamer2]

Ken, I promise I'll prove-read my post next time

At the same corner I squeal tires, I actually did it everytime, and I couldn't brake without doing that, unless I really want to brake very deep into corner and risk carrying too much momentum into the corner.

I was refering the braking zone before entering to the corner, it was a steep downhill which I could carry more than 90-100mph into the braking zone....

 

[nsxtasy]

I could be wrong, but... I think it is possible to lock the brakes and get tire noise with ABS. What the ABS does is, when you brake hard enough to lock the tires, it quickly unlocks them by releasing the brakes enough to get the tires to turn and gain traction, then allows the brakes to engage again. This is the cycle that the ABS goes through, and the ABS system allows it to happen several times a second, more frequently than you could do manually.

As long as your ABS is working, at low speeds as well as high speeds - meaning, you can engage the ABS (by stomping HARD on the pedal) and feel the pedal pulsing - I wouldn't worry about it.