Road and Track: Spied 2011 M5: With its twin-turbo V-8 pumping out nearly 600 bhp, the all-new BMW M5 is poised to take back the title of World's Best Sports Sedan.
You obviously either didn't read my post correctly or just don't understand the subject!
You have pick on Brembo why? I was referring to any multi piston apposed caliper against slid type calipers used by BMW on all their cars. Brembo is the market leader and best known which is why I mentioned their name and for no other reason. Advantages of multi piston opposed caliper arrangements are many:
OEM caliper is of a sliding design, with the piston or pistons on only the inboard side of the disc. While this type of caliper is inexpensive to manufacture, it is generally extremely heavy, and inherently flexible, both of which are to be avoided on a performance braking system. Conversely, Brembo's type of multi piston calipers are fixed mount, opposed piston calipers cast from aluminium alloy. Despite being much larger and many times stiffer than the original caliper, they are also much lighter. The calipers are equipped with differential piston bores in order to eliminate pad taper. Without this feature, the leading edge of the pad will wear more quickly. This can cause problems such as cocking the pistons in their bores, which can damage or seize them. Increased fuel economy and reduced rotor running temperature due to the pistons retracting and allowing the pads back off the disc when not braking. Another function of this is when at rest (e.g. car parked) after hard use the pads aren't in contact with the discs allowing even and quicker cooling which stops the discs warping and the heat transferring and 'boiling' the brake fluid.
Eliminate hot spots on the discs and pads which cause the discs to warp in normal use and this also gives better wear characteristics of the pads and discs... eg longer life
Better feel and modulation from the stiffer construction.
Many many more reasons FOR the multi piston construction. Now the for’s for the sliding piston caliper:
Allows the use of a bigger brake to wheel ratio due to increased clearance of the caliper on its outer side face from not having the bulk of pistons here... This is NOT an advantage on the E60 M5 as the wheels and brakes are plenty big enough and with out any clearance issues.
The only other advantage is its CHEAP to manufacture... so guess why BMW use them!
I could go into a lot more detail but I believe the above gives you a good over view and may educate as to some of BMWs decisions
You have been lucky, yes some owners track their cars and either through luck, driving style or track design get away without brake problems many many others don't and is well docummented on the Wed, forums and in reviews and magazines, now I know this is a function of the cars weight BUT BMW market this car with track aspirations... check out the original M5 brochure page 44 and 45 where they detail a track session with the M5 at the Nurburgring! Its not marketed as a solely a exec sedan just for comfort and high speed cruising which is how MB DO market their machines.
I for one would gladly pay a little extra for ALL the benefits of multi piston opposed brakes. Specially as I HAVE pushed them beyond their best!
If you have any more questions I would be happy to help. And hopefully this has been cogent qualitative criticism
Regards
Jay
I feel smarter just by reading this! thank you for the information/insight. I have been pondering about upgrading the brakes on my 08 M5. Any suggestions?
I feel smarter just by reading this! thank you for the information/insight. I have been pondering about upgrading the brakes on my 08 M5. Any suggestions?
Most seem to go with the Brembo GT setup or the AP Racing equivalent.
Personally, if you are going with the B GT setup, and plan to get wheels at any time in the future, I'd get some 20" rims and then opt for the 405MM rotor kit. Might as well make the most out of upgrading your brakes...
Brakes, in my opinion, are millions of times more important than almost anything else. There is no such thing at all as having too much stopping power.
All the many brake system suppliers are good, StopTech, Brembo, AP etc etc
Unless you race and drove each back to back or against each other you probably couldn't tell the difference between the BBK's
Make sure you get a road based system as apposed to a out and out race system, the difference is that the road systems have dust/dirt boots on the pistons to stop the pistons binding and damaging the inner pressure/fluid seals.
I'm not sure you need to go up to the 405mm disc's as these are much heavier and I think the standard size is capable and has suficent area and thermal loading capabilities, its the caliper design that needs upgrading to give real and definate gains in both feel and performance.
You obviously either didn't read my post correctly or just don't understand the subject!
You have pick on Brembo why? I was referring to any multi piston apposed caliper against slid type calipers used by BMW on all their cars. Brembo is the market leader and best known which is why I mentioned their name and for no other reason. Advantages of multi piston opposed caliper arrangements are many:
OEM caliper is of a sliding design, with the piston or pistons on only the inboard side of the disc. While this type of caliper is inexpensive to manufacture, it is generally extremely heavy, and inherently flexible, both of which are to be avoided on a performance braking system. Conversely, Brembo's type of multi piston calipers are fixed mount, opposed piston calipers cast from aluminium alloy. Despite being much larger and many times stiffer than the original caliper, they are also much lighter. The calipers are equipped with differential piston bores in order to eliminate pad taper. Without this feature, the leading edge of the pad will wear more quickly. This can cause problems such as cocking the pistons in their bores, which can damage or seize them. Increased fuel economy and reduced rotor running temperature due to the pistons retracting and allowing the pads back off the disc when not braking. Another function of this is when at rest (e.g. car parked) after hard use the pads aren't in contact with the discs allowing even and quicker cooling which stops the discs warping and the heat transferring and 'boiling' the brake fluid.
Eliminate hot spots on the discs and pads which cause the discs to warp in normal use and this also gives better wear characteristics of the pads and discs... eg longer life
Better feel and modulation from the stiffer construction.
Many many more reasons FOR the multi piston construction. Now the for’s for the sliding piston caliper:
Allows the use of a bigger brake to wheel ratio due to increased clearance of the caliper on its outer side face from not having the bulk of pistons here... This is NOT an advantage on the E60 M5 as the wheels and brakes are plenty big enough and with out any clearance issues.
The only other advantage is its CHEAP to manufacture... so guess why BMW use them!
I could go into a lot more detail but I believe the above gives you a good over view and may educate as to some of BMWs decisions
You have been lucky, yes some owners track their cars and either through luck, driving style or track design get away without brake problems many many others don't and is well docummented on the Wed, forums and in reviews and magazines, now I know this is a function of the cars weight BUT BMW market this car with track aspirations... check out the original M5 brochure page 44 and 45 where they detail a track session with the M5 at the Nurburgring! Its not marketed as a solely a exec sedan just for comfort and high speed cruising which is how MB DO market their machines.
I for one would gladly pay a little extra for ALL the benefits of multi piston opposed brakes. Specially as I HAVE pushed them beyond their best!
If you have any more questions I would be happy to help. And hopefully this has been cogent qualitative criticism
Regards
I am not aware of anyone documenting any braking deficiencies with the E60 M5.
I've experienced significant brake fade in my car. Admittedly, I'm running stock fluid and pads, but I (literally) get 5-7 laps, including warm-up laps, before the pedal gets mushy. When I've tracked the car, I've never pushed beyond 6/10ths (I have the Panoz for 10/10ths), my driving style isn't punishing on brakes, and the local track only has three decent braking zones per 1:30 lap. The stock brakes simply can't dissipate the energy of a 4,100 lb car going 100+ mph.
If I were going to track the M5 more often, I'd upgrade the brakes immediately, the suspension as soon thereafter as possible, find a way to drop 500lbs from the car, and only then even think about touching the engine.
I wouldn't get too excited, its a very very small % increase, for the same reasons you get a increase in performance again very small and not by anymeans a reason to spend thousands on a BBK, it would take you years to recover the costs lol!
I've experienced significant brake fade in my car. Admittedly, I'm running stock fluid and pads,
.
While the car can be tracked, I think that was outside BMW's design parameters. Everything is a compromise, I am sure they choose the pad for good life, and low noise. The car can probably do a few high speed decels on roads like the autobahn in stock configuration.
Before you dump $$$ into a new brake setup for just running a few days on the track at 6/10's, try better pads, some Motul and make sure you are getting air to the brakes. You should see a big improvement for very little money.
Regards,
Jerry
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'01 Black/caramel
Dinan Stage 3 suspension, SS jet coated headers, ESS SC kit, open brake ducts, Hamann front splitters, TEC cupholder, U.S.(Euro style) tilt/slide armrest, 6k HID fogs, 6k super white low beams, V1/Stealth1, dual head LI, 2.65 diff w/40% lockup/2x dynamic, compact spare, Euro trailer hitch, Mocal oil cooler, ACS type rear spoiler, Rogue custom SSK and tranny mounts, ST 355 BBK (fronts), BP sway bar brackets, Bluetooth retrofit
Just another data point regarding the M5 stock brake capabilities. I've done 40+ track days on my '07 M5 6sp at high speed tracks such as Road Atlanta, Sebring, VIR and most recently Daytona. I use Motol 600 fluid always freshly flushed before each event but rotors and pads are stock. The brakes lose initial bite when way heated up but have never lost stopping power. . . even repeated laps slowing from 174 to 45 coming into infield turn one at Daytona. Could they be better. . . sure. . . but they are not a limiting factor on the track. Now if only the 6sp manual tranny was up to the task like the brakes are. . . still overheats and forces pitting in after about 15min of hard track driving. Ugh!
Here's some in car-video from a couple laps at Daytona. M5 could use some weight loss in the tight infield but it rocks on the high banks. . . . . . wonder why Mr. Lutz didn't choose Daytona for the CTS-V challenge?
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. . . wonder why Mr. Lutz didn't choose Daytona for the CTS-V challenge? 
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