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      01-04-2009, 12:28 AM   #1
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Will there be a caliper only upgrade from anyone?

Since we have something like a 360mm rotor already, it would be nice to just get some FIXED calipers with larger pad area. Then we could use the stock 18's as track tires and not run out of brake at the track.

I understand there's no interest from the big brake manufacturers since it'll obviously steal sales, but I'm sure there's a market for suck a kit.
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      01-04-2009, 01:06 AM   #2
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Quote:
Originally Posted by aus View Post
Since we have something like a 360mm rotor already, it would be nice to just get some FIXED calipers with larger pad area. Then we could use the stock 18's as track tires and not run out of brake at the track.

I understand there's no interest from the big brake manufacturers since it'll obviously steal sales, but I'm sure there's a market for suck a kit.
Rotora did a 4-piston caliper kit for the E46 M3, and it is expected to have one for the E9x M3 in an unknown date.
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      01-04-2009, 01:16 AM   #3
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What makes you think you will run out of brake endurance at the track with SRF and track pads? Have you tried HT10s or RS19s and good fluid yet? The mechanics of the brakes on the M3 are pretty good.

Brake cooling is the biggest gap, not the the caliper or pad size.
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      01-04-2009, 04:17 AM   #4
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Good track pads + fluid will be more than enough to cover most braking from track.
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      01-05-2009, 11:42 PM   #5
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But would it be so bad to have a FIXED caliper? I though the 135 brakes felt much better than the the M3 brakes in terms of pedal feel.
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      01-06-2009, 10:15 AM   #6
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anyone know how much the rotora's for the e46 were...or have a guess as to what the upgrade would cost for the e9x
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      01-06-2009, 01:59 PM   #7
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Quote:
Originally Posted by Technic View Post
Rotora did a 4-piston caliper kit for the E46 M3, and it is expected to have one for the E9x M3 in an unknown date.
Probably a few years from now...
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      01-06-2009, 02:10 PM   #8
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Quote:
Originally Posted by Blip Bavarian View Post
anyone know how much the rotora's for the e46 were...or have a guess as to what the upgrade would cost for the e9x
I got the first kit a couple of years ago for $2300... I would guess no more than $2500 for an M3 E9x kit with a 6-piston front/4-piston rear combo (the E46 kit was 4-piston at all corners).

They had a Holiday special for a full big brake kit (15" rotors all around with 8-piston front and 4-piston rear calipers, brackets and SS lines) for $3850.
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      01-06-2009, 07:37 PM   #9
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Stoptech would be my best guess. They've made caliper-upgrade kits before for many platforms. Personally, I'd love a fixed caliper...4 or 6 piston...that would allow a wider range of pad choices and a quicker change-time of pads. I also believe that multi-piston calipers, for the most part, offer a better modulation-feel than sliders.
We'll see...
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      01-09-2009, 02:53 PM   #10
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It really doesn't make much sense from a manufacturer's standpoint to offer just a front caliper upgrade -- most of the time, at least. It's like offering an cool new iPod, but it works on the old Blackberry operating system. Not many companies will risk hard-earned performance gains and their reputations using the OE components. It's not a good day when you hear someone complaining loudly about their brakes when its got your name shouting from the face of the caliper -- and then finding out later they had a rotor problem with someone else's components. There is no good way to recover from that, so why do it?

Although this can be done successfully on certain rear brake applications, the front simply runs too hot with the right nut behind the wheel. The aluminum hat and floating or strap drive disc arrangement provides quite an advantage that is totally lost with just a caliper upgrade. The pin drive composite Ate rotors are an improvement over a standard 1-piece disc in terms of weight, but are no match for the performance of a proper 2-piece arrangement.

I've loved many BMW's since my first one - an E28 M5 (if only the E60 M5 was as much fun to drive that hard!). That car had 4-piston front calipers and had great pedal feel. Nearly all of the current Bimmers are still on sliders, which stop the car well under "normal" use, but sacrifice pedal feel at the limit without question. Even though the 135i gets the a 6-piston Brembo up front, that caliper has shown to be fine for the street and inadequate for serious track duty. However, it does feel quite a bit better than a 335i with the sliders.

It's generally considered that anyone serious enough to change to fixed, opposed-piston calipers could also be serious enough to push their car very hard. If so, a full upgrade is the way to go. Brake upgrades are not for the car -- they are for the driver. If you don't drive hard enough to need the upgrade, then you either don't buy them or do it just for the looks if you've got to have them.

Even BMW has a whole boatload of accountants, so the engineers don't win every battle. They have got to make compromises for comfort and reliability -- call it the "customer experience". They do not sell track cars down at your local dealership (well, OK, Lotus does, but I digress...). However, there are race shops all over that will prep a car for their serious customers, and that always means serious brake upgrades and generous cooling for almost all car makes.

(Note: If anyone reading this is a bling dude, ignore what I just wrote and go out and buy the biggest saucers and the brightest red calipers you can find to rock behind those 22's on your ///M -- or maybe your 525i with those cool ///M emblems you got off of eBay baby!)
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      01-09-2009, 03:23 PM   #11
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Quote:
Originally Posted by Technic View Post
I got the first kit a couple of years ago for $2300... I would guess no more than $2500 for an M3 E9x kit with a 6-piston front/4-piston rear combo (the E46 kit was 4-piston at all corners).

They had a Holiday special for a full big brake kit (15" rotors all around with 8-piston front and 4-piston rear calipers, brackets and SS lines) for $3850.
$2500 for a 4 wheel upgrade. That's cheap. Last time I looked 4 wheel upgrades were close to $5k.
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      01-09-2009, 03:36 PM   #12
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Quote:
Originally Posted by HIS4 View Post
$2500 for a 4 wheel upgrade. That's cheap. Last time I looked 4 wheel upgrades were close to $5k.
E46 M3 front and rear calipers only, for $2300...
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      01-09-2009, 04:09 PM   #13
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Quote:
Originally Posted by AP Racing - Chris_B View Post
It really doesn't make much sense from a manufacturer's standpoint to offer just a front caliper upgrade -- most of the time, at least. It's like offering an cool new iPod, but it works on the old Blackberry operating system. Not many companies will risk hard-earned performance gains and their reputations using the OE components. It's not a good day when you hear someone complaining loudly about their brakes when its got your name shouting from the face of the caliper -- and then finding out later they had a rotor problem with someone else's components. There is no good way to recover from that, so why do it?

Although this can be done successfully on certain rear brake applications, the front simply runs too hot with the right nut behind the wheel. The aluminum hat and floating or strap drive disc arrangement provides quite an advantage that is totally lost with just a caliper upgrade. The pin drive composite Ate rotors are an improvement over a standard 1-piece disc in terms of weight, but are no match for the performance of a proper 2-piece arrangement.

I've loved many BMW's since my first one - an E28 M5 (if only the E60 M5 was as much fun to drive that hard!). That car had 4-piston front calipers and had great pedal feel. Nearly all of the current Bimmers are still on sliders, which stop the car well under "normal" use, but sacrifice pedal feel at the limit without question. Even though the 135i gets the a 6-piston Brembo up front, that caliper has shown to be fine for the street and inadequate for serious track duty. However, it does feel quite a bit better than a 335i with the sliders.

It's generally considered that anyone serious enough to change to fixed, opposed-piston calipers could also be serious enough to push their car very hard. If so, a full upgrade is the way to go. Brake upgrades are not for the car -- they are for the driver. If you don't drive hard enough to need the upgrade, then you either don't buy them or do it just for the looks if you've got to have them.

Even BMW has a whole boatload of accountants, so the engineers don't win every battle. They have got to make compromises for comfort and reliability -- call it the "customer experience". They do not sell track cars down at your local dealership (well, OK, Lotus does, but I digress...). However, there are race shops all over that will prep a car for their serious customers, and that always means serious brake upgrades and generous cooling for almost all car makes.

(Note: If anyone reading this is a bling dude, ignore what I just wrote and go out and buy the biggest saucers and the brightest red calipers you can find to rock behind those 22's on your ///M -- or maybe your 525i with those cool ///M emblems you got off of eBay baby!)

Chris, that's for the insight.
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Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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      01-09-2009, 05:31 PM   #14
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The other issue has already been recognized that under hard/extreme/repeated use, the weak link in the brake system is heat capacity.

We all know that if your OEM brakes can exceed the grip provide by the tires then you typically do not need any more braking power. For the most part our brake systems are not designed to provide greater amounts of brake torque, but rather maximize the efficiency of the system and improve temperature management. While the stock brakes will lock up the tires on the first few hard stops, after a few more you will induce fade and your stopping distances will continue to lengthen.

The first few steps that most people take are braided lines and a high performance brake pad. This is good for providing a slightly firmer pedal feel and getting a pad that has a wider temperature range to match the intended driving style. For a handful of people the wider temperature range is just enough to get them away from the possibility of pad fade. For others it simply gives them a few more aggressive stops before the fade returns due to a heat soaked disc and boiling fluid.

The next intermediate step, would be introducing more airflow to the system in the way of brake ducting. Now you have larger amounts of fresh air being introduced to the system and you have found a way to lower the consistent operating temperature. This is a great step and something that you see on practically 99% of true race cars due to the efficiency. The problem here is that (1) I can't think of anyone off hand that has developed a proper duct kit for the M3, and (2) the attempts that I have seen do not come close to being able to deliver enough airflow to lower the temperatures enough to eliminate the chance of fade. At this point you have already spent about $500 on front and rear pads and brake lines.

Now you're thinking about a caliper upgrade.

A caliper upgrade will undoubtedly deliver a few improvements to the M3.
(assuming it's developed with quality manufacturing and proper engineering)
It will more than likely be stiffer and lighter than the OEM sliding caliper. With the appropriate piston sizes the pedal feel will remain similar, but response and modulation may be improved. In a best case scenario it will have a larger pad shape which will provide more swept area for longer pad life (Note: The new pads will be more expensive.), and with the proper pad you will still have a friendliness to the disc. The larger pad volume can also (even though very minor) act as a heat sink for a tiny bit of added heat capacity. Keep in mind I am speaking in terms that relay how this kit would be marketed to the consumer. This is regardless of whether it is realized in actual use or not.

You've probably spent $1600 - $2000 depending on which brand jumps at the chance to develop the caliper only upgrade, + the money you already spent on pads and lines. At this point you have not really done anything that has significantly added heat capacity or reduced operating temperatures. Besides the improved look behind the wheels, you are back in the same place as before with fade issues. If by chance this caliper upgrade provides increased braking forces either by larger piston area or increased coefficient of friction (based on pad selection and caliper efficiency) it will lead to adverse effects in heat management by increasing the braking temperatures at a faster rate.

The most common question I have been asked in the last few months is why did Brembo not develop a 355mm brake kit to attempt to fit under factory wheels. The short but very direct answer is heat capacity. The OEM disc is a 360mm, with a tall annulus, and thick walls. That creates a disc that alread has significant amount of heat capacity even though during extended track use it becomes not enough. A 355mm (and even our 365mm) disc would have been a reduction in heat capacity as compared to the OEM disc. Rather than creating something purely based on aesthetics and an obvious market demand, and without ssuming that our improved metallurgy, vein design, and wider airgap would be enough improvement on it's own to maintain consistently lower temperatures, FEM (finite element modeling) proved otherwise in the early staged of our R&D.

The good news is that we did our best to make sure it would fit the OEM 19's so at least there's an inexpensive option for 1 set of wheels. If you're a serious track guy chance are you'll eventually end up with 2 sets of wheels, one for the track and one for street. There are a few 18" wheels currently (with more coming soon due to our influence with the top wheel manufacturers) that fit around our 380mm system that can become your track wheels. All of these that come to mind are lighter than the OEM wheels making them the better choice for your track tires. The 19's become your street tire and you're braking problems are solved.

It's not a cheap endeavor, so I'm sure most of you will be hoping that the first stage of pads and lines work out. We did make sure though, that our BBK option will be the final step in your braking needs.
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      01-11-2009, 12:23 AM   #15
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Thanks Gary. What about making a thicker rotor? I believe the 135 stock rotor is pretty thick compared to most rotors. Wouldn't that help with heat management without increasing rotor diameter?
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Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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      01-11-2009, 10:57 AM   #16
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The stock front rotor is 30mm thick. Stoptech and Brembo rings are 32mm. That does not buy you more thermal storage based on the rotor design, but it does provide much more thermal transfer with the 2-4mm wider fins and better fin design.

I think Gary hit the nail on the head, someone needs to design a cooling system that is bolt-on. The stock system will be fine with fluid and 1600-2000 degree racing pads, but it will run very, very hot, which will wear out components more quickly. On my E46, the stock system with DTC70 pads and fluid would never fade, even after an hour of abuse on slicks at 9-10/10ths, but I would go through a set of pads in a day, and the pad wear was distorted, not to mention that under extreme temps and stress the OEM brakes would start to respond in "new" ways.

I would pay up to $1-1.5K for a very well designed and easy to install/remove cooling duct system for the front brakes. This on its own would likely remove the need for a BBK, assuming the front brake calipers do not deform under stress like the E46 units did. The new design is pretty seriously beefed up compared to the E46 unit.
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      01-11-2009, 12:02 PM   #17
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Quote:
Originally Posted by GTM View Post
Good track pads + fluid will be more than enough to cover most braking from track.
What do you recommend for track pads? I do not beleive that the fluid will make much diference at all unless you are constantly going around non stop for at least 5 laps or more.
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      01-11-2009, 12:38 PM   #18
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What do you recommend for track pads? I do not beleive that the fluid will make much diference at all unless you are constantly going around non stop for at least 5 laps or more.
Sure. The big one is the pads. The best pad available in our size is the hawk HT10, and only available for the front caliper. Not a "Great" pad, but it is the only high friction racing pad available right now. I'd guess that the DTC70 and PFC01, which are much better pads, will follow quickly this year. I will pair up the HT10s with Ferodo DS2500 in the rear, which are not racing pads, but have a higher MOT and friction coef than stock. I'd much prefer to run the same compound on all corners though. Pagid makes an RS19, but that's not a good pad for heavy cars in my experiance, they tend to crumble.
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      01-11-2009, 12:45 PM   #19
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Quote:
Originally Posted by jml View Post
Sure. The big one is the pads. The best pad available in our size is the hawk HT10, and only available for the front caliper. Not a "Great" pad, but it is the only high friction racing pad available right now. I'd guess that the DTC70 and PFC01, which are much better pads, will follow quickly this year. I will pair up the HT10s with Ferodo DS2500 in the rear, which are not racing pads, but have a higher MOT and friction coef than stock. I'd much prefer to run the same compound on all corners though. Pagid makes an RS19, but that's not a good pad for heavy cars in my experiance, they tend to crumble.
Thanks. Is it available for the E92 M3s?
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      01-11-2009, 01:30 PM   #20
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I have looked at a friend's 135 M Sport and it seems their 6piston (appears to be brembo) calipers looks very promising. So if their calipers can be had for a decent price plus a set of brackets, that should be a more viable solution.
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      01-11-2009, 01:35 PM   #21
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Quote:
Originally Posted by jml View Post
Sure. The big one is the pads. The best pad available in our size is the hawk HT10, and only available for the front caliper. Not a "Great" pad, but it is the only high friction racing pad available right now. I'd guess that the DTC70 and PFC01, which are much better pads, will follow quickly this year. I will pair up the HT10s with Ferodo DS2500 in the rear, which are not racing pads, but have a higher MOT and friction coef than stock. I'd much prefer to run the same compound on all corners though. Pagid makes an RS19, but that's not a good pad for heavy cars in my experiance, they tend to crumble.
Pagid RS19 pads are on a par with PF-01s. I think the Pagids may be more compatible with the stock pads as well. They are available for both front and rear, also. I'd go to PF-Z pads for street use if I use PF-01s on the track. PF-01s are definitely my favorites.

Regarding pad wear with stock calipers: Did you run the solid caliper bushings on your e46? They completely cure the uneven pad wear.
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      01-11-2009, 01:36 PM   #22
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Quote:
Originally Posted by Dartanium View Post
I have looked at a friend's 135 M Sport and it seems their 6piston (appears to be brembo) calipers looks very promising. So if their calipers can be had for a decent price plus a set of brackets, that should be a more viable solution.
This is getting more confusing now I am just trying to see what fits an E92 M3 in terms of friction pads...
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