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View Poll Results: What solutions have worked/not worked for your brake cooling at HPDEs | |||
Bending the splash shield helped significantly | 4 | 28.57% | |
Bending the splash shield did not work | 1 | 7.14% | |
Bending the splash shield not noticeable | 1 | 7.14% | |
I found a brake duct kit to fit 135i (please tell us where!) | 0 | 0% | |
I installed a custom brake duct kit | 0 | 0% | |
I never had a problem with brake cooling | 8 | 57.14% | |
Voters: 14. You may not vote on this poll |
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09-13-2011, 03:54 PM | #1 |
Corridore Italiano
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Update on Brake solutions...
So I recently got hooked on HPDEs with the 135i at VIR. First time I went out, I kept everything completely stock to get to know the car. Immediately noticed the limitations of the brakes and the horrible understeer, so this past weekend I went out with these upgrades:
The first two days of the weekend I ran the performance friction 1038 pads that came with the Stoptech kit. Although these are better than the stock Brembo pads, I kept getting brake fade even during the beginning of the sessions. So the last day, I put in some Hawk HT-10s (rated up to 1300F) up front. The aftermath is shown below. Completely split the pad in half. Assuming its not a manufacture defect, a possible reason for overheating was the front brake bias, given that I kept stock pads in the rear. Ken at KNS Brakes (highly recommend him to you guys) is going to get me some Carbotech XP12s for the front (2000+F) and put XP10s in the rear (1600+F). Hopefully this along with some bending of the splash shield will solve the heating problem, but many I have talk to blame our poorly designed cooling system. Those with the M-bumpers have brake ducts, but they don't direct air at the brakes, just the wheel well in general... Any moderately serious weekend HPDE people should look into brake cooling. This was only my second school and although I was driving pretty fast, I am only at an intermediate level. Someone needs to step up to the plate and start making a legitimate brake duct system for our cars. Ken is going to look at the car and see what solution we can come up with. If anyone has any suggestions/comments surrounding my experience or brake pad/rotor cooling in general, please share here so that those interested in driving their car any harder than beginner groups at HPDEs can have some resources. Last edited by mpatrone; 09-13-2011 at 06:43 PM.. Reason: HT-10s are rated to 1300F not 1600F* |
09-13-2011, 04:13 PM | #2 |
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Whoops...
I voted that bending the shield helps.. Pixieblue will be here shortly and link you to his thread about cutting the plate and bending it back nearly 90 degrees for even more cooling.. I even have a thread for making custom backing plates that include scoops in them to pull air from the stream of air in the wheel well.. You didnt mention Brake Fluid after putting on the stoptechs???? infact you didntmention brake fluid before the stoptechs?? If you were getting fade after only the first couple of sessions with stoptechs, then i must question your driving style ( read : not ability , not insulting) I run BMW BBK, which is basically 135 brakes w/ ate blue and i get no fade...I had some vibration issues from my cool carbons and all ihave run is with Bent plates... (lime rock / summit point / NJMP / Pocono ) I have a sensation that you are way to hot into the turns, and you may have made it worse with the camber plates, because the car will actuallly turn now so you go in faster. Stop techs are some amazing brakes... it just doesnt make sense ?? I could be wrong, ut its just my .02
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09-13-2011, 04:18 PM | #3 |
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Sorry, didn't mention it because I thought it was implied
Bled with ATE Typ 200 before each track day, and when the BBK was installed, the computer fully bled the system (including ABS and DSC) |
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09-13-2011, 04:19 PM | #4 |
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very surprised with your choice of racing pads after two events. hopefully you don't intend to daily drive on them. below is a pic of my cool carbon pads after 7 track days. I run in the advance group
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09-13-2011, 05:35 PM | #6 |
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The conventional wisdom is that beginners brake too lightly for too long and also overbrake (slow down too much). Maybe that explains why Pixelblue gets 7 days from Cool Carbons and I get 4 days and someone else got 2 days. Are there other differences in technique that affect how long the pads last?
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09-13-2011, 06:27 PM | #7 |
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Last year, I ran (at intermediate level) Cool Carbon's with ATE fluid for 5 track days with no real overheating issues, other than the vibrations which seem to plague the CCs. I did fab up some diy brake ducting with some 3" dryer hose directed at the hub, but I didn't do any modification to the shield, so I'm not sure if it really made a difference.
I took the car out for 1 HPDE this year with stock pads on the front with nothing more than OEM ducting, and while I definitely noticed a decrease in braking performance over the CCs, I still had no major issues. I was definitely pushing the car harder than last year too as I shaved off 3 seconds from the last time I was timed at NJMP Lightning. I did notice some fade, but the OEM anti fade system seemed to do the job with keeping the pedal feel pretty good. I would have to agree that it may have to do with driving style. From experience I know that at the first few track days, most drivers will tend to ride the brakes a little longer and not brake as hard which will actually put more heat into the brakes, than if you waited until the last moment and really got on the brakes hard to enter the corner. Not saying that's what you are doing, but it might be worth it to pay attention to your braking style. It took me a while to get used to braking late. Also, I've never run VIR, so I'm not sure how it is on brakes in general, but that kind of failure on a quality BBK seems out of place.
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09-13-2011, 06:40 PM | #8 |
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This is interesting to me once again....I do not remember hearing things like this a couple years ago with regards to the 135i's brakes. What MY is your vehicle? I wonder did BMW make a minute change over these last couple years? I have NEVER had any of those issues (and I brake pretty late..in intermediate group). I vote driving style...no way StopTechs should have been showing those types of symptoms....
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09-13-2011, 06:40 PM | #9 |
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The first thing I did when I got fade was to talk with my instructor about my braking technique and he said that he didn't think it was the issue. We switched from the street/track pad to the HT-10s and everything worked fine. He was surprised to see the picture of the pad separation, and confirmed again that he doubted technique was to blame. I'm doing all the braking as late and quickly as possible, rarely holding the brakes except for turns that require trail braking.
VIR has some really intensive braking sections, especially on turns 1, 4, and 14. At 1 you are braking from around 130 down to about 60 or so. Here's a video of one of my laps to get an idea: Again, I'm open to any constructive criticism so if anyone does something in my technique that is to blame, berate me. p.s- I might have engaged ABS in that video, but that rarely happens (maybe once or twice during a weekend when really pushing myself) |
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09-13-2011, 06:42 PM | #10 |
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^^^Cool I wanna watch the video and comment tomorrow! Bedtime in my part of the world
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09-13-2011, 07:08 PM | #11 |
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From looking at the vid it doesn't seem like you were braking early, and there only seems like two, maybe 3 really hard braking zones. Maybe the Carbotechs will do the trick. I run xp10/xp8 on my Miata and I can romp on them all day long with no issues. Granted, that car is 1000lb lighter and they key to driving fast with only 116 hp is using the brakes as little as possible, lol. Was there anyone else there with brake issues?
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09-13-2011, 07:20 PM | #12 |
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I am a little confused. Are the pictures you have posted (OP), of pads from a stoptech big brake kit on your car after a HPDE with Kumoh XS's?
Just looked at your video. Everything seems fine, and there is so much time inbetween those big braking zones there should be no issues. More so, with the big brake kit, which is increasing rotor mass, and braking torque; to do that kind of dammage to the pads, you would be overwelming the tires well before your brakes gave out. I have the XS's on my car for street tires, and theres no way they have coeficent of friction to cause an issue like that, unless you were really romping the crap out of the car. After just watching your video, your driving great, I agree with your instructor %100!. Even if you were on R-comps I still don't think its that likley. From the looks of those pads, you have a piston in that kit thats seized, or the pad was not floating freely and cocked on a pin or slide. Look at the wear on the bottom pad in your picture! What do the rotors look like? Last edited by xerox445; 09-13-2011 at 07:33 PM.. |
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09-13-2011, 07:25 PM | #13 | |
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Not that I'm aware of. Most of the other people in my group (green) weren't getting anywhere near the same type of braking forces as I was.
The other drivers in the intermediate/advanced classes usually had weight reduction and/or were track prepped cars with brake ducts. Moreover, I only saw one other car with a 6 piston front setup (minus vettes/911s?), with everyone else running single piston or 4 piston fronts. One would think that the larger slotted rotors (355x32mm) and 6 piston setup would have much improved cooling, which leads me to believe that brake cooling is the main issue here. I have to reiterate that I was running stock pads in the rear, which probably caused front bias. Remembering that these are 3200lb+ cars we are trying to slow down, so the question is whether making the front brakes work harder/heat up more caused the failure or was a pad defect to blame. The separation only happened with one pad, with the rest only having chipping/small chunks come off on the edges. Quote:
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09-13-2011, 07:36 PM | #14 |
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Yes. It was a 3 day HPDE weekend, and I ran Friday and Saturday with performance friction 1038 pads up front on the Stoptech ST-60s (i think these are the "z rated" street/track combo pad) and stock pads+calipers in the rear.
My driving and braking techniques improved very quickly over the weekend, so I found another driver at the event with a 6 Piston Stoptech kit (same size pads) who had an extra set of Hawk HT-10s. He only had a few events on the pads, so they had plenty of pad life left (maybe ~30% used?). I installed the pads at the end of Saturday at the track and drove home (1hr). The pads were kept on through Sunday night when I switched back to street pads after the drive home. |
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09-13-2011, 07:37 PM | #15 |
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I run in the advanced group and threshold brake for short periods of time. I have done 3 events in the past month with a 4th this weekend. The first two were stock with new fluid and Hawk DTC 70/60 pads. I experienced fade at the end of all most each 25-30 min session.
I removed my dust shields this past weekend when I was at Hallett. I still got brake fade at the end of a hard 25 min session. Granted, I did not have brake ducts running straight to the hubs, but with no dust shields, you would think I would be seeing some improvement. |
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09-13-2011, 07:54 PM | #17 | |
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Just in case the picture isn't clear, here are pics of each pad. #1 is the one that cracked completely in two.
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09-14-2011, 04:51 AM | #18 |
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Micro cracks on racing pads are OK, however losing the whole pad material is new to me...
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09-14-2011, 08:20 AM | #19 |
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personally I don't have any experience with hawk pads but this is not the first time I heard about their pads crumbling and getting destroyed. you may want to look into pagid or performance friction pads for your next set.
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09-14-2011, 09:07 AM | #20 |
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Yeah, that was the first thing I decided. The Hawk HT-10s are only rated to about 1300F, so I ordered some new pads through Ken at KNS brakes. We are putting Carbotech XP12s in the front (2000F+) and XP10 in the rear (1600F+). Hopefully putting track pads at all 4 wheels and some more serious compounds will solve this problem, but I will also try the shield mod to get some extra air flow at the brakes.
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09-22-2011, 10:05 PM | #21 | |
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