Left Rear Brakes Hanging at COTA
 

I’m over my head with some brake issues I had 2 weekends ago with Chin at COTA. I had issues with lots of front end shake 2 weeks before with Edge Addicts at COTA. Had a cracked front right rotor. Replaced all 4 rotors with Stoptech slotted rotors and after talking to Mike Jr at Carbotech, went with XP20 front and XP12 rear pads. Saturday the brakes were amazing. There was lots of track dust because they were grinding the track smooth for the upcoming MotoGP event. On Sunday during the first session after warm up, still cool outside, it felt like my rear left brakes held as I backed off hard breaking at turn 15 and I spun. Went to hot pit and then back out on track. About the 100 meter marking I started hard breaking on the back straight. Again, Letting go with hard breaking, the front end went hard left and I ended up going backwards with brakes jammed full on down the straight and through the turn. I’m also running Castol SPF fluid and have the Z1 stainless steel lines. Running 18” square on Maxxis Victra RC-1. 275/35/18. Front camber of -3.6, front castor 7.0 and -0.01 toe in. Rear camber -2.9 and -.11 toe in. My Nissan mechanic inspected everything and can’t see any thing wrong. He did some 80-0 hard stops with no issues. Running HPDE3 with NASA in May, but no idea what to do with brakes. Looking for some input. Thanks

Caliper Rebuild would be one guess if you feel there are piston issues. When was the last time you rebuild them, heat destroys the seals quickly and dust and debris can get into the piston area though I don't recall anyone ever reporting problems even with pretty destroyed seals. XP20/12 is considerably higher then most people use but I don't think that's an issue. Also what are your tire temps afterwards if you have that?

Thanks for responding. I have never had my calipers rebuilt and have probably 15 race weekends over the past 2 years. COTA is also a brake intense track. At the suggestion of the guys at Carbotech, I went with the more aggressive pads. I’m not taking tire temps, but think I should start. The session where I spun was the first one of the morning after a few warm up laps. I had my wife in the car for that and was not driving near max effort. The outside temp was probably mid to high 50’s at the time and I had only ran 1 lap. Started tires at 30 psi all around. On the day before, after session pressures were getting up to 38/40. And interesting, there was lots of dust from the track grinding. The first day looked like we were running on a dirt track

You run with the VDC off? And have you done the YAW sensor mod? With the VDC off. The system is still not deactivated completely. If it senses the car getting a little out of shape. It will activate a rear brake caliper to straighten the car out. Regardless where you are pointing. I've had this happened to me. :eek: With your aggressive choice of pads. This could be your problem.

:iagree:

Maybe have too much pad on there, too. ICE mode is real. You have brake ducting? COTA is evil on brakes.

Ice mode is when you stomp on the brakes and have a nice pedal. But the ABS decides it's not having any parts of this slowing process at the monment. The ABS gets a serious brain fart. :eek:

I’m running with VDC off. But have not done the yaw sensor mod. Have been running VDC off for over 2 years and have maybe 8-9 weekends at COTA, but with less brake compound. I was running Xp12’s on the front and Xp10’s on the rear. I’m beginning to think I need to go back to the 12’s and 10’s. Most likely the Xp 20/12 combo was overloading everything with harder later braking. Also need to figure out some brake ducting. My Nismo doesn’t accept the Stillen cooling ducts readily.

I used the Stillen brake duct kit from the rotors to the front. I was lucky enough to get real Nismo RC brake ducts. But you can get other ducts now. To reduce from the 3" duct to 2" hose. Use a reducer.

https://www.facebook.com/groups/2321...7200413662263/

https://www.facebook.com/finiteelementdesign/?fref=ts

Dust collection reducer 3" to 2". Cut it down to fit. And glue into place.

https://www.cpooutlets.com/jet-41482...SABEgJRwPD_BwE

Rusty, thanks for the brake duct info. I’m sold! With Texas World Sppedway done for, COTA has become my primary track. If any track warrants brake cooling, its COTA.

You can paypal me my consultant fee. :rofl2:

I have some XP20 front and XP12 rear pads - one COTA weekend only on them. Oh, and a used set of RE-11s.

There is always more than one way to skin a cat and I agree with the others that you using way to much pad and you need to do the yaw sensor mod or get tuned with ecutek. I used APR ducts and reducer like Rusty with a Stillen brake cooling duct system.

https://farm5.staticflickr.com/4721/...0bcbcdac_b.jpg

Hotrodz, that looks like a nice clean install. I have a Nismo and Rusty sent me in the right direction for the intake ducts for a Nismo. I think it’s a unanimous descion I was using too much brake. The guys At Z1 said so as well. Only one who didn’t think so was Mike Jr at Carbotech.

LOL, mine is a Nismo too but my front bumper has been modified to allow for more air flow, the hood has been modified with vents to let hot air out, the rear wing has been removed for bigger one and more down force and the whole suspension and drive train has been upgraded but still a Nismo!!!

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Yeah, the Nismo from HELLL! :driving: :tup: