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Brake issues on the track
Took the FRS to lime rock when I first got it and overheated the brakes 2 laps in. Wasn't too smart knowing the stock pads would do this anyway. So since then I've changed a bunch of things: steel braided lines, ate blue stuff fluid, centric blanks and carobtech p10 pads. Hoping this would do the job but mid way into my first session this passed weekend, same thing happen. Obviously not as bad but still started getting that soft pedal feel and bad brake fad.
I don't want to have to do a big brake kit since they're a ton of money. Any suggestions on what else to get around this. Maybe brake ducts could help a little? Mod list: intake, front pipe, cat back, ecutek tuned on e85 by Visconti. |
DOT unapproved brake fluid, yo.
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Never ran at Lime Rock, but I tracked at PittRace this weekend which is decently hard on brakes. No fade in all 4 20 minutes sessions. I run Carbotech XP12's F/R and Motul RBF 600 fluid.
Mods are RCE Tarmac Springs, Koni yellows, front bar, 245 BFG rivals. What tires are you running? |
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What kind of tires are you on? (Make, model, and size) Are you running XP10 front/rear? XP10 is great for intermediate level guys, but if you're quick, XP12 is the way to go (assuming you want to stick to Carbotech). If you're in a hurry, I believe we have it in stock. It's very possible that they were bedding the 1st session; did the brakes improve later? ATE generally is not suited for quicker drivers. I'd recommend trying Motul RBF600. If that doesn't work, step up to Project Mu. If that doesn't work, then Torque RT700. This isn't a FR-S/BRZ, but this picture is from the past weekend, with Project Mu 999, and Torque RT700. One of the rotors cracked during cooldown, but the brake fluid didn't get mushy, and the pads never faded. https://fbcdn-sphotos-c-a.akamaihd.n...61617586_o.jpg |
did you bed the pads/rotors in?
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almost sounds like you are not applying your brakes aggressively enough. when you are on the track you should be braking much harder. When you drag the brake like you are rolling up to a stop sign looking for the smooth stop you will boil your fluid really fast
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Proper bleeding of the system as well as proper bedding in of the pads is important, but the stock style rotors need better cooling.
Check out my build thread for my solution. I installed the Touge Factory brake cooling kit which features ducts, hoses, and a proper backing plate that helped tremendously at the track. I can drive 9 or 10/10ths now on track and the brakes are consistent into every corner. Also get a master cylinder brace, that helps a lot with solidifying the pedal feel in threshold braking situations. |
First off, let me get this one out of the way, I hate Carbotechs, and always had issues with them. Are the pads bedded properly? Carbotech has specific directions on properly bedding them.
I'll notice a "soft" pedal after a cool down lap going into a hard braking turn, as the pads have cooled down significantly, but usually 3 to 4 seconds in the bite gets progressively better. Soft pedal sounds like a fluid issue. There could be air in the lines or you could be boiling the fluid, but I don't think Lime Rock is the kinda track that would boil fluid. I ran ATE at Sebring on all my cars without issue (CTS-V, Miata). If the pedal feels still kinda firm, but theres no bite, pads could be glazed. Take them out, rub them against the concrete, and re-bed. One thing that not a lot of people think of is pad knock-back, which I had an issue with on my Miata. It is when the lateral movements through the corners will push the pads out from the rotor surface, so when you go to the brakes, pedal goes to the floor for the initial pump, and is definitely a butt-clencher. I do a light brake tap in the straights before the brake zone by habit after my Miata race car, so I wouldn't know if this car had that issue or not. |
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Going to order rear pads this week, do y recommend going with xp10 or xp8 for the rear. I just got the xp10 for the fronts so going to just burn them out and go with xp12s next time around. Only issue is the car is daily driven so I didn't want to go with such an aggressive pad. As for brake fluid, I guess ate isn't cutting it for me. Going to switch over the motul this week. Running it at njmp next week which requires more use of brakes. |
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Yeah, you're quick. You're fading the XP10 fronts; I did some informal testing with just XP12 front/stock rear, and I was fading them after just a few hot laps, so a drive of your caliber has to be feeling the pain. I suppose I should mention, brakes on this car wear much faster than on a Miata... |
Do you know how to properly bed-in (or burnish) Carbotech's?
You have to brake from 60mph to 10mph 3 times on a summer day with the sun at the 4 O'clock position all while crossing all the fingers on both hands and praying to Vishnu with a memorized chant that will be provided by Carbotech. What's wrong? Didn't cross all of your fingers? Well, UNEVEN TRANSFER LAYER FOR YOU! http://3.bp.blogspot.com/-62mERgzUrZ...s_soupnazi.jpg |
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When I was learning how to race, I was destroying my brakes. I was on them too early, too little and for too long and entering the corner too slow. Just a change in driving fixed it all. Brake late, brake hard, carry more speed into corner. (But be safe!) |
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I think I went from 62mph to 11mph 3 times at 4:15 pm. probably I had all kinds of issues with the Carbotechs. |
I am surprised no one reccommends Castrol SRF. I know it is expensive but it last much longer and requires less bleeding. I have never had good luck with ATE.
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If you can spring for it Endless fluid is the best but not sure how it will react with the OE seals. |
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Regarding the XPs, you do know they need a special bedding procedure along with either new rotors or rotors that have been used with ceramic based pads, right? You shouldn't put Carbotech XPs on your rotors that have been used with the stock pads. The car is also my DD, and except a slightly annoying noise at low speed and copious amount of (wheel friendly) dust, it is no problem. There is plenty of cold bite. |
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Essex has nice instructions and theory on bedding new pads on their site. If I understand (disclaimer - not an engineering type), after bedding a pad and laying down a transfer layer, driving at street speeds erases the transfer layer through friction. A new transfer layer must be re-created by putting heat into the brakes through a bedding-in procedure. The cycle can be repeated. However, track pads will likely have undesirable characteristics when used on the street.
Do those procedures not apply with Carbotech pads? Why must the disc be resurfaced or new if stock pads have been used when changing to Carbotech pads? Anyone know what happens if one DOESN'T follow their bedding procedures? Will the world really end? |
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I've always done it just to err on the side of caution, especially if you're going to be putting that much stress on the system. I'm no expert though. |
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Lol Mike, I know that. I think anyone who is a decently fast driver knows what it is like to be held up by rich guys in there 100k+ cars. They just want to run flat out. Back when my dad used to take his formula continental to the Porsche club events in Corpus for practice, the 11th fastest time of one particular weekend was a guy in a race prepped dodge neon. He said that guy was consistently in the top 15. |
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[ame]http://youtu.be/cSqzS02fy3Q[/ame]
Video i put together from this passed week at Lime Rock. |
Re bedding Carbotech pads/ need for new or resurfaced discs:
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Are Carbotech pads unique, or is the theory the same for ALL pads? Why don't other manufacturers recommend the same process? Why, Why, Why? |
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