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BMW 3-Series (E90 E92) Forum
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To BBK, or not to BBK, that is the question
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09-20-2012, 06:00 PM | #1 |
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To BBK, or not to BBK, that is the question
I've melted both the left and right stock front brake piston dust boots. I don't notice anything yet... but it's getting disconcerting. Other than pad dust, it's pretty clean in the front calipers as we don't see much rain in Colorado. I am running Pagid Yellows pads at the track. Do BBKs have the same issue, or is it time to simply get a dedicated car? ("Not to BBK" for this car would give me a nice chunk of change to start with a 944, for example.) With the extra disc area of BBKs, I assume the temps stay lower and thus less chance of stuff melting. I'd love to hear your opinion. Cheers.
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09-20-2012, 08:26 PM | #2 |
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The total heat generated will be the same no matter what size brakes you use, but as you notice, the larger and better designed rotors will radiate the heat away more effectively.
The properly designed calipers will also reject far more heat keeping the pistons and therefore piston seals cooler. The seals will also be more robust, preventing such a problem. So yes, this won't be a problem with a proper BBK. |
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09-20-2012, 11:26 PM | #3 |
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However, the answer to your question isn't that straightforward. If you are at the point where considering a dedicated car is an option, that may be the better route in the long run. Lighter car will be less $$ on brakes, tires, etc in the long run.
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09-27-2012, 05:44 PM | #5 | |
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10-08-2012, 02:21 PM | #6 | |
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I am debating the same thing and decided to get better rotors and pads at the stock sizes. I bought the RB Performance rotors that replace the stock ones and will be running PFC 08 pads this weekend at the track. If this is not sufficient then I would buy the BBK. By the way I have found that you pay a hefty price to buy the entire kit and can probably piece the parts you need for less than a full kit. You probably already have the SS lines (I'm asuming). I have found Stoptech calipers for the BBK at ~$1000 each and the 2 piece rotors at ~$450 each. That makes the price about $5800 for the 4 corners vs $6800 from **********s.com. Add pads since usually the pads that come with these kits are not ones I would consider to use for the track. Just something to think about. N54_Fan |
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10-08-2012, 03:58 PM | #7 |
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BBK's can be had for much less when you can find a good "street price".
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10-08-2012, 05:46 PM | #8 | |
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Harold maybe you know the answer to this,...I understand that some people only do the front BBK and leave the stock calipers. Would this upset the natural brake bias that BMW has engineered? I would think so. If that is the case is it possible to use the FRONT calipers in the rear with the 345mm BBK rotor size? Since the front is 345mm and the BBK rears are 345mm why couldnt I upgrade just the front calipers until I am ready to do the rears? This way I use the front stock calipers AND rotors as the rear set until I am ready to shell out another $2000 or so on the rear set. Is this doable? Thanks. |
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10-09-2012, 09:44 AM | #9 |
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Alex, have you ever used an infrared temp. scanner on your rotors after you have tracked them? I was hitting upwards of 500°F in the pits after a session a couple weekends ago, but I have no clue what is considered hot.
2-piece rotors may be at least worth a shot to help shed some of the heat and transfer less of it back to the caliper. |
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10-09-2012, 11:51 AM | #10 | |
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10-09-2012, 12:16 PM | #11 | |
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Please PM me your current set-up so I can help you further. |
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10-09-2012, 01:10 PM | #12 | |
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It won't work. The only reason(s) why most front only kit works, is that the overall surface area of the multiple pistons are no larger than the factory single piston size, so the brake proportioning remains the same while brake torque, heat capacity and dissipation has increased thus improving overall efficiency.
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10-09-2012, 02:07 PM | #13 | |
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The stoptech 335i kit is 4x30mm, 2x36mm... unless the stock piston is ~70mm, then the stoptech caliper would have more piston area. If the front piston is 60mm, then stoptech has considerably more... |
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10-09-2012, 03:58 PM | #14 | |
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06-24-2014, 01:14 AM | #15 | |
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The way to calculate the overall piston area on fixed caliper is to take the overall area on ONE SIDE only. I.E. You count only 3 pistons on the same side in a 6 piston set. Don't ask me why. I don't know why. That's just how it is.
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