Car:
2008 CR - Stock

Description of problem:
While on a road course running weekend track events, when braking hard at the end of long high speed (112-118mph) straight, my brake pedal is solid as a rock on initial engagement.

For a very short moment of time, the brake pedal will not move, it is absolutely solid, then immediately returns to normal usage with all the braking that is expected.

The rest of the turns on the track the brakes are fine. Plenty of pedal. No fading. No "spongy" feel.

I cannot recreate this issue on the street.

What have I attempted to deal with it?

Changed out the OEM brake fluid with Super Blue DOT 4
Changed OEM pads for Hawk HPS

Niether of which have had any positive impact on this particular issus.


Comments? Thoughts? Suggestions? Perhaps someone else has delt with this or has knowledge of how to solve this isssue?

I'd really appreciate some input before I spend any more money trying to fix this.

 

did you flush out all the oem brake fluid? If not can dot 4 be mixed with regular oil?

 

Did you inspect Brake Booster lines? Idk, but maybe at your 'high speed run' the brake booster isnt getting enough vaccum? idk? just throwing thoughts out there.

 

the factory DOT 3 "heavy duty" was cooked.

had Bullitt Proof Performance perform a thorough flush of the system.

Thing is... factory DOT 3 or Super Blue DOT 4 - issue is no different.

The pedal feels better and more precise with the better fluid, but the issue is the same regardless of the fluid (at least comparing OEM vs SB)

 

it's a thought....

never considered this angle. not sure how it would cause it. but at this point I'm game for any suggestions. Thank you for the input.

 

i can't tell if it's brake fade you're describing... if it's brake fade you're experiencing, it might be just that hawk hps aren't really a track pad at all and ate blue doesnt really cut it either if you're driving really hard. you might just need some race pads and some motul brake fluid.

 

^Well, he does say it grabs well AFTER the initial non-bite.

BY the way, your car is DBW...is the brake pedal somehow electronically activated as well? maybe theres some lag time figureing out how hard to activate the brakes?

 

that is correct. After initial engagement, brakes are great.
and brakes are great everywhere else on the track.

only issue appears to happen at the end of long straights that enter a hard braking zone.

somehow, speed appears to be related. Above 110mph this happens consistly. If I run the same straight and cruise at 100mph before hitting the zone, the issue does not happen.

 

http://en.wikipedia.org/wiki/Brake_fade

Is this at all what you are describing?

 

Sounds like pad fade. I had that happen once on NJMP Lightning, pretty scary. You went beyond the temperature range of the pads, and what you described is exactly what happened to me. Did you check the pads after that track day? My bet is that they were glazed pretty good.

Time to get some real track pads on there. Through some research on my own, I've gathered that the Hawk HPS pads aren't anything special at all. I'm running Carbotech XP 10 (front) & XP8 (rear) for track days, it would be a good idea for you to look into them. The last thing you want on your mind while flying up to a turn is whether your brakes will be there or not.