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11-09-2009, 01:27 AM | #67 |
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i agree with the OP 100%, i have fried my brakes on the canyons and now my master cylinder needs to be replaced. The OEM Brakes are not strong enough for tracks, canyons, or extended performance driving. BBK on the Way
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11-09-2009, 05:24 AM | #68 |
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Junior ....... what brand/model pad were u running @ the time?
i've cooked many so-called 'race' pads on OE systems. The 2 major negative factors on this OE brake system are: 1- The Single-Piston design limits you to a small size pad. This smaller pad will overheat faster/easier as there is less pad surface. 2- The alloy used on this OE caliper is more prone to harbor & KEEP heat trapped. On this OE system the use of a thermal barrier (like titanium plates) between the Pad & Caliper helps dramatically, due to the caliper's poor heat dispersion. And actually 'painting' the OE Caliper with special heat-resistant brake caliper paint helps with this. At 4000lbs. and using the OE brake system, i recommend: - PFC01 or DTC-70 pads only - Titanium (or other material) thermal barrier plates - SS Lines - Castrol SRF or Motul fluid - Painting the calipers with 'brake caliper paint' - Junior's Brake Cooling Duct DIY - And most important, 4 hot laps max = 1 cool down lap (on a 2 min. course), 3 hot laps max = 1 cool down lap (on a 3 min. course) Last edited by mastek; 11-09-2009 at 08:15 AM.. |
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11-09-2009, 12:14 PM | #69 | |
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1. Pad surface area will not significantly alter rotor temperatures. They may, when combined with multi-pistons slightly change caliper temperature. What is important is not the pad mass but the combined system thermal mass and the rotor contributes so much more it drowns out the effect of pad mass. 2. I call BS on a problem with the OEM caliper alloy. That would require that you know which alloy it is and you don't. There is not a great deal of difference in the alloys used for brake systems. Sure casting and forging will probably use different alloys but their specific heat and thermal conductivity will be very similar. 3. Titanium pad plates or any other thermal barrier will slightly increase rotor and pad temperatures and slightly decrease caliper temperatures. The only real solutions are less car weight, less braking, heavier rotors or more cooling. Heavier pads and calipers would offer very little improvement. In short the energy generated will typically be constant (driver, track, car, etc. equal) redistribution of the energy is not so important compared to thermal and cooling capacity. 4. I also call BS on caliper paint having any benefit on performance/thermal performance.
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11-09-2009, 01:44 PM | #70 | |
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1. its common sense - a smaller pad area will retain more heat - just as smaller rotors do. 2. 'It' would not 'require' the knowledge of the exact alloy or alloy mix used -- as I am not a metalurgists and that information would be useless to me. What is required; is 'experience' with different cars and their calipers and various bbk's and actually witnessing a difference in temperatures, which is where I am coming from. BMW OE calipers are infamous on the track for cooking rotors and pads due to the cheap alloy used. 3. Again, 'in my experience' titanium thermal barrier plates between the pad and caliper help to keep the caliper cooler and extend pad life (minimally) 4. Call BS all you want -- I suppose you think that BBK's come painted for looks. The paint acts as a thermal barrier which keeps the calipers a bit cooler. It seems like a common sense: 1/64" paint barrier, no?? It's alot easier to see the difference between BBK's that perform well at the track vs. BBK's that do not vs. OE brake systems vs. Modified OE brake systems .... when you have actually had experience with all 4 at the track in the same car with the same compound pad. But a basic common sense law would be to copy what works (looking at BBK's that actually do) - Thats why we started putting SS Lines on OE brake systems - Thats why OE brake systems began featuring multi-piston setups - Thats why you want a bigger rotor and now I say paint your caliper to help with heat -- |
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11-09-2009, 08:03 PM | #71 | |||
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Calipers are painted for two reasons. 1. Bling, 2 Environmental protection for the aluminum which is subject to corrosion and chemical attack, of course not like steel, but it is still vulnerable. In reality the paint will act as an insulator. I seriously doubt it can signficantly alter the radiative cooling of the caliper. So, yes, I do call BS.
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11-09-2009, 10:13 PM | #72 |
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I had some time to think about the failure during my flight from Amsterdam to Lax today.
What worries me is that with the following set up: - Race pads (i'll get te specific pad and brand later) - SRF Brake Fluid - My DIY Brake system cooling ducts There is NO WARNING what so ever that the brake system is failing. My car drove fine for an entire morning. With the pads wearing and heat increasing in the brake system. It suddenly failed. The caliper got stuck. Further heating up the system. The braking was fine in La Source on the start of my 5th or so hot lap. On the initial braking for Malmedy Le Combes the brakes were gone. I was lucky there was run off. And no cars in front. I almost didn't touch the brake pedal for the rest of the lap to cool down. And when i got into pit late the disk was glowing. I have experience brake failure on cars before. The stopping power decreases, fading sets in, you sometimes hear the brakes. etc. I think the SRF Fluid in combination with race pads is 'to good' for the brake system. The SRF and pads can withstand the heat, but the caliper breaks, gets stuck, or the o-rings melt inside. (whatever happened) I don't know if the blister on the brake line formed during the hot laps, or during the 'cooldown' lap with the caliper stuck. But this could have turned in to a nasty crash! So you get no warning that you have a developing problem... I think a brake fluid with a lower max temp would be safer. Then you can feel if your pushing the thermal limit of you 'OEM System' by the brake fade.
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11-09-2009, 11:06 PM | #73 |
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I'm catching up here so excuse me if this has already been said but is the failure only on the left front, what's the pad thickness of the right front pads?
Could it be a sticky LF piston from a bad or stressed piston seal leading to brake drag? That might explain the red hot rotor, deformed caliper/pads and blown line. Even the slighted bit of drag leads to escalating heat---more heat, more drag, more heat. It appears that the system had no chance to shed it. Did you notice any brake drag on turn-in? |
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11-10-2009, 01:10 AM | #74 |
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The AP Racing website has a bunch of information on it as well. Here's what they say about rotor temperatures in a racing application:
Under racing conditions disc bulk temperatures should normally be maintained in the range 400°C to 600°C for best performance. Disc face peak temperatures may be higher but should not exceed the maximum recommended for the pad material being used.Note that this is specific to racing applications. PFC01 or similar racing pads, really big ducts, and calipers with no dirt seals (they leave them out so they don't burn up). |
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11-10-2009, 06:19 AM | #75 | |
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My thinking is the caliper and piston are dissimilar metals so they heat up at different rates. If the piston heats up faster it could expand faster than the caliper bore. That coupled with the uneven pressure and the soft rubber could cause the piston to wedge itself into the bore. If it wedged while the piston was extended then the pad would constantly be contacting the rotor causing it to heat up very quickly on that one side only. The heat transfers through the rest of the braking system causing all of the other failures. Keep in mind, I'm not expert by any stretch of the imagination, just going over in my head how it could have happened. |
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11-10-2009, 07:12 AM | #76 | |
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11-10-2009, 05:39 PM | #78 | |
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I think even the BMW engineers will agree their 1-piston stock setup will not last through the abuse the OP put the them through. |
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11-11-2009, 12:28 AM | #79 | |
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1. Less abuse by a talented pro. 2. Brake duct cooling system with air directed right at the rotor. 3. A larger heavier rotor with improved hat design to take advantage of the duct cooling (i.e. most BBK rotors). 4. Stainless steel brake lines. 5. The highest temp race pads available RS-15 or Turner race pads or the like.
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11-11-2009, 02:07 AM | #80 |
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Great thread.
If you put together stock rotors, racing brake fluid, aftermarket pads, r-compound tires, a professional driver and 5 hot laps on one of the most punishing tracks in the world for brakes you get brake brûlée. Not much of a surprise. All the components put together were never tested as a system in conditions like these. This post explains pretty well the events that led to the failure. The M3 brakes are not sexy enough by today's market standards but I believe they are very good brakes even in stock form. They could be better under continued heavy use. FYI here are the brakes on the M3 (FNR-AL 1 piston), M5 (2FNR-AL 2 piston) and Mercedes S65 AMG (2FNRV-AL 2 piston 4 pads). It is not just BMW that uses floating calipers in high end cars. |
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11-11-2009, 03:19 AM | #81 | |
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I still believe if you are going to do some serious tracking with your M3 a brake upgrade is a good idea, like the Performance Friction kit. Most people would get away with pad upgrade, stainless lines, motul fluid, etc. |
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11-11-2009, 03:34 AM | #82 | |
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A talented pro is more likely to better manage brakes on track. 2. The OP DID have brake cooling ducts directed @ the center of the back of the rotor. 3. The OE rotor is 360x30mm ..... most popular BBK's on the market (and for race teams) for these heavy cars is 355x28mm ..... If you put a 380mm kit ... you limit the wheels size to 19's (and maybe one 18 set) So what are u talking about? 4. Correct 5. PFC01 > anything else And again, the higher the piston count -- the bigger the pad size -- the bigger pads distribute the friction, contact-area, heat build-up better. |
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11-11-2009, 07:49 AM | #83 | |
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If you have larger pads, they will initially experience less of a temperature rise since they have more mass. Is that what you mean? If it is, that is probably not all that meaningful during extended operation as the mass of the pads will always be significantly smaller than the mass of the rotors, and if your rotors are really cooking, the mass/size of your pads doesn't matter all that much--rest assured they are cooking as well for most intents and purposes. You would have to have gigantic pads to make a significant difference.
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11-11-2009, 09:10 AM | #84 |
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stupid question, but could you use your parking brake to save your ass in a situation like this? I mean i know it wouldnt provide much stopping power, but wouldnt it at least help you slow down?
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11-11-2009, 11:31 AM | #85 | |
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11-11-2009, 12:54 PM | #86 | |||
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That may indeed be correct. I was not saying the examples I used were "the best". However, to substantiate your claim you should provide some real data on these pads. Something along these lines. Link.
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11-11-2009, 12:56 PM | #87 |
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JuniorM3: Choose a BBK for your baby, get her back to the same track and push just as hard. If you can share the results with us it will be a wonderful data point on the quality of the kit you chose! Thanks again for a good discussion.
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11-11-2009, 01:01 PM | #88 |
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Junior .... you still have not mentioned what pads you were using at the time?
If its a sponsor issue .. please PM me ... thanks Last edited by mastek; 11-12-2009 at 09:02 AM.. |
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