Race Tracking Your Supra - Information exchange

[garudathree]

opinion of a slow guy: any time I’ve had concerns re brake system performance, I have pulled in vs driving through it, unless it was basically a free track. Usually not worth plowing into someone else imo.

I’ve only experienced what you described with previously severely overheated pads, or cold carbon ceramic brakes on the outlap.

iirc in both scenarios the pads never shifted into the adherent mode of friction

abs ice mode is another possibility, but I haven’t triggered it yet

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[Todday1]

I had experienced something similar with some of the street/track level pads as they out ran their operating temp ranges. What pads are you running and what are their temp ranges.

 

[kaj]

I had experienced something similar with some of the street/track level pads as they out ran their operating temp ranges. What pads are you running and what are their temp ranges.

Hawk DTC60. I was nowhere near their limit, I've been using them all season.
Range is 400℉-1600℉.
This was 100% not a pad issue. The next stop was normal. I only had it happen twice, all day. No open recalls for my car.

 

[Todday1]

agree those are great pads so then would think it could be something With master cylinder/brake boost/Abs controls etc. Please let us know what you find out.

 

[Rensuhlo]

Hit up Atlanta Motorsports Park.

 

[FLtrackdays]

what's the industry standard for windshield treatment these days? have used rainx/aquapel before, hoping for something more effective:

I‘m scheduled for a windshield film & treatment in late November. Said I won’t be able to use my wipers and won’t need to. I’ll have to ask him what they are going to use. Trying to prevent further cracking/ replacing windshields.

Hawk DTC60. I was nowhere near their limit, I've been using them all season.
Range is 400℉-1600℉.
This was 100% not a pad issue. The next stop was normal. I only had it happen twice, all day. No open recalls for my car.

That sucks man! Definitely shouldn’t be the pads. Have you flushed the brake fluid recently?

 

[kaj]

That sucks man! Definitely shouldn’t be the pads. Have you flushed the brake fluid recently?

Yes. In fact I never had a problem with the brakes until I flushed them. Can't imagine I did anything wrong, could be coincidence.

 

[FLtrackdays]

Yes. In fact I never had a problem with the brakes until I flushed them. Can't imagine I did anything wrong, could be coincidence.

Unlikely you did anything wrong. But… most issues are fluid related imo. I had a stalemate in Miami/Homestead, newer Supra program driver finally driving solo. He just did a flush, had new pads and was getting some mushy pedal. I got in the car & the pedal felt firm. So I asked him to try bleeding out any bubbles. He did and viola! Problem solved. It was worth a try instead of going home, early on a Saturday morning.

Granted, you’ve been doing this for a long time. So I know you’ve seen cracked rotors, glazed ones, faulty pads but it still comes back to fluid most of the time. And why I bleed the ? out of mine. It’s excessive. But like popping a pimple, kinda satisfying seeing all that dirty fluid and occasional micro bubble pass through the clear brake bleeder line.

I hope that’s all it is ? Otherwise, I do keep an extra set of rotors lying around. You could always switch pads and rotors. At least the cost has really come down for our cars.

 

[kaj]

Unlikely you did anything wrong. But… most issues are fluid related imo. I had a stalemate in Miami/Homestead, newer Supra program driver finally driving solo. He just did a flush, had new pads and was getting some mushy pedal. I got in the car & the pedal felt firm. So I asked him to try bleeding out any bubbles. He did and viola! Problem solved. It was worth a try instead of going home, early on a Saturday morning.

Granted, you’ve been doing this for a long time. So I know you’ve seen cracked rotors, glazed ones, faulty pads but it still comes back to fluid most of the time. And why I bleed the ? out of mine. It’s excessive. But like popping a pimple, kinda satisfying seeing all that dirty fluid and occasional micro bubble pass through the clear brake bleeder line.

I hope that’s all it is ? Otherwise, I do keep an extra set of rotors lying around. You could always switch pads and rotors. At least the cost has really come down for our cars.

Brakes were perfect 90% of the time so not pad or rotor related.

 

[razorlab]

Brakes were perfect 90% of the time so not pad or rotor related.

When it happened, what was your application like? Hard stab, light maintenance braking, threshold, etc?

I noticed that the longer you are on the pedal it does a weird fake ABS thing where the pedal goes away until you press harder. Only happens on HARD threshold braking for me, and very rarely.

 

[AHP]

The brake pedal feels normalish. Maybe a little stiff. No vibration from ABS or anything, just like the calipers are locked out or something.
I bought the car with 1900 mi on it so I'm thinking no recall.
It's doing this almost once per lap. Cost me a pretty serious off into the dirt That may have cost me first place today.

Sounds very similar to Ice Mode that happens on C7 Corvettes (maybe prior gens too, but have never invoked on my C8). Think late brake, HARD and fast stab on the brakes -- the pedal moves a bit and gets hard like stepping on a block of wood and you have maybe 50-60% of the anticipated brake force. If you lift and reapply it's normal. I vaguely recall encountering that on my Supra a few times but could have been pad fade...

 

[kaj]

Sounds very similar to Ice Mode that happens on C7 Corvettes (maybe prior gens too, but have never invoked on my C8). Think late brake, HARD and fast stab on the brakes -- the pedal moves a bit and gets hard like stepping on a block of wood and you have maybe 50-60% of the anticipated brake force. If you lift and reapply it's normal. I vaguely recall encountering that on my Supra a few times but could have been pad fade...

Sounds right. Wouldn't be pad fade because letting off and reapplying the brakes doesn't cool them down enough to make a difference.
I recently started left foot braking so wonder if it has something to do with my time going from full throttle to full brake. Maybe I need to slow it down a bit.
I never, ever had a problem while Just using my right foot.

 

[kaj]

When it happened, what was your application like? Hard stab, light maintenance braking, threshold, etc?

I noticed that the longer you are on the pedal it does a weird fake ABS thing where the pedal goes away until you press harder. Only happens on HARD threshold braking for me, and very rarely.

Hard braking from about 115mph to a tight left hander. Very hard, probably almost to the point where ABS would have kicked in. Or, maybe it did and this is what happened.

 

[razorlab]

Hard braking from about 115mph to a right left hander. Very hard, probably almost to the point where ABS would have kicked in. Or, maybe it did and this is what happened.

Did it feel like it did a little kick back? If so, that is that stupid faux brake fade/abs thing the system has. it's annoying but as long as I just push in harder it clears up. I've never felt like I was going to crash because of it.

 

[AHP]

Did it feel like it did a little kick back? If so, that is that stupid faux brake fade/abs thing the system has. it's annoying but as long as I just push in harder it clears up. I've never felt like I was going to crash because of it.

I think that's what I was experiencing a few times. I was already hard on the brakes but the pedal felt weird, almost crunchy, and when I pressed harder out of desperation there was more there.

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