Race Tracking Your Supra - Information exchange

[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.

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[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.

 

[Nocturnal]

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.

I wonder if you have air in the ABS module if it’s only coming on at or past threshold braking?

 

[theQuaybee]

That sounds like a bubble in the line or something to me. If you haven't re-flushed since this started, I would just do another flush to rule that out. Especially since you said this started after your last flush.

 

[kaj]

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.

No. It just felt solid. I thought it was normal, but I was so busy thinking "WTF now I'm gonna go off".. so maybe the pedal was harder than I'm remembering. LOL. The car slowed but just barely. When I got back on the brakes after, they were fine.

I wonder if you have air in the ABS module if it’s only coming on at or past threshold braking?

I had no air when I bled. No air allowed into the reservoir.

That sounds like a bubble in the line or something to me. If you haven't re-flushed since this started, I would just do another flush to rule that out. Especially since you said this started after your last flush.

That's where I'm at right now. Bleeding is free so will try next weekend and cross my fingers.

 

[AndyK5]

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.

This happened to me this weekend. About 3 sessions in, during one abs activated hard brake the pedal moved a bit more than it normally would, I felt a crunch at the pedal and had to press harder to get the same stopping power, which caused increased stopping distance and me to miss my turn in point...nothing dangerous but less than optimal obviously.

I had no air when I bled. No air allowed into the reservoir.
That's where I'm at right now. Bleeding is free so will try next weekend and cross my fingers.

So yes it sounds like air in the system but from what you are saying no air was allowed. Unless there was some that was already in there...it could be from factory or an air bubble formed after many track days that traveled up in to the abs module. In any case if someone posts how to do an ABS included brake flush (without a trip to the dealer) I'd do it with you as I am super picky about my brake feel and as I said above I have felt something similar this weekend.

 

[Rocksandblues]

Wish I had something to help. Sounds very frustrating
Haven’t encountered anything like this after 100+ track days w the Zupra I would need to drive the car and look at the components to be helpful. Wish I could

Sounds bad- but I would completely change fluid and pads.
If it still happens it is an ABS/software issue

Fwiw I change out fluid twice a year, 4 sets of pads, one rotor. I have a set of products that works- I ain’t changing

 

[Islindur]

Verus swan in da house. Spring 24, 5k usd..

 

[PaulFRDE]

Hi everyone,

Thank you very much, for this thread, lot to read and to think!

I just finished my season, this car is a beast even with the EU engine. My car is fully stock except brakes, and I want to modify it as little as possible.

That said, I have been thinking about installing aftermarket front and rear sway bars to improve the behavior in the some corners (especiqlly the chicanes), and hopefully compensate a bit for the lack of camber on stock suspension/height/geometry.
Also, it just looks stupid how much it lifts on some tracks

I searched in the forum already but feel like everybody is directly switching to coilovers.
Is anybody on stock shocks/height and aftermarket sway bars? Any thoughts if this is worth it, for a track and mountain road perspective?
I know mounting the rear swaybar is a b*****, so any comment is welcome to help me take a decision

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