Front tires lock up under heavy braking

[SaberX]

So - I first noticed this during a track day, after which I had the ABS system checked out by Acura - who said that it was working just fine. The lockup happens for about 1 second before the ABS kicks in but its kinda like "screech -screech - screech" Not like any ABS car I've driven before. So I'm not quite sure what it is. Also, sometimes I feel the ABS trying to kick in but I don't have an audible screech however I still feel like the wheels are sliding (moist weather or when the tires aren't hot is usually when this happens) because the steering wheel is pulling left and right and shaking but the car is still going in a straight line. I was wondering a few things:

1) I have 17/18 combo on the car and its a 91 - so I know those tire sizes aren't what the computer expects - does this affect braking or just TCS?

2) I think the rotors have been beat on pretty hard. Would getting new OEM rotors help? I heard if the rotor surface isn't flat your brakes can lock prematurely.

Finally, any brake gurus out that have anymore info to offer to a spirited driver with 2-3 track days a year- that would be great. As it stands I really don't feel comfortable with the stopping power of the car.

Thanks in advance.

 

[burbel]

I could be wrong, but that sounds exactly like what I always thought was my ABS system working as designed. From what I know of older ABS systems, you lock the tires, then the ABS system unlocks them, rinse, repeat.

 

[NSXDreamer2]

Brian, I don't think you need to worry about it... Too bad I haven't had a chance taking you out for a ride, my tires screech before I dive in turn 3, turn 5 and turn 8, probably turn 2 too, but I wasn't paying attention...

ABS is preventing the tires lock up for "extended time", when you reach the tires' adhesion limit, it will compliant... your ABS works fine. That said, I really don't like my 17/17 combo for track. I have a lot of fun with the OEM 15/16 set up, even with Kumho tires. (That's what I've been using on all my events last summer.)

Unless you feel the ridge at the rotors' edges or you experienced rotor wrapping, you don't need new rotors. However, I remembered the guy who sold your car had trim the calipers to fit those RPM2's. Don't know if that make any difference on track. Even with a little rotor pulsation, it doesn't mean you need new rotors.

 

[polar]

Hi Brian, Like every other said, you don't have to worry about what you going through, because I experienced the same thing with what NSXdreamer2 said, specially at turn 3.
I'm not sure if you need new rotors, but you will probably need some dedicated pads for track if you are looking for better stopping power, even it doesn't sound very cost efficent when you only track the car 2-3 times a year.
Are you still running the kumho 712s? I would suggest getting some different tires after you done with those. The 712s are very wallet friendly tires but I don't think it's suitable for track.

 

[Andrie Hartanto]

That's the way the older ABS works. It doesn't work very good.

 

[NSX-Racer]

That's the way the older ABS works. It doesn't work very good.

That's also the way my '98 ABS works. It works somehow good IMHO with street tires but astonishingly much better with race slicks (no squeel).

 

[slashmatt]

I was just reading this.

There's a pretty good section in there about the brakes. Apparently the ABS system in the NSX is pretty good for racing. According to the writer, the ABS system is race bred. I'm not sure if that's why it feels different from some other cars I've had in the past or not. But, I agree, it is different.