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.
True, but I think this has reached critical mass way beyond that time period. My daughter was watching something on the Disney Channel today, and they had a commercial teaching the kids how to take a power shower, to save water. Total BS. As a parent I'm more concerned with hygeine, not a stopwatch. Total indoctrination. I've never seen so much crap shoved down our throats. This has already gone so much further than I ever thought it would. Can't believe BMW, Porsche, and others are succumbing..... Et Tu Brute?
I hope you are right. However, I will hold on to my V10 as long as I can. I can imagine the size of my grandkids eyes popping open 15 years from now just seeing a V10.
OK, now that we have completely hijacked this thread, consider this story: I recently was filling up my Tahoe. Suddenly, some woman I did not know started mouthing at me for driving a "gas-guzzling SUV." I tried to ignore her but she persisted. I then told her that of the three cars I have (e60 M5 and e36 M3 track car), the Tahoe is the most fuel-efficient, so I was actually saving gas by driving my V-8 Tahoe with the lower towing gears. She didn't quite know what to do with that revelation.
__________________
2006 M5 Silver Gray/Silverstone/Madeira Walnut
Dinan Stage 2 Suspension System
Supersprint Race exhaust with X-pipe
1998 M3 Coupe Technoviolet Track car
JRZ RS, Kirk roll bar, Racetech 4000W seats, GC sway bars, control arms, AA headers and 3" race exhaust (loud and proud), etc.
OK, now that we have completely hijacked this thread, consider this story: I recently was filling up my Tahoe. Suddenly, some woman I did not know started mouthing at me for driving a "gas-guzzling SUV." I tried to ignore her but she persisted. I then told her that of the three cars I have (e60 M5 and e36 M3 track car), the Tahoe is the most fuel-efficient, so I was actually saving gas by driving my V-8 Tahoe with the lower towing gears. She didn't quite know what to do with that revelation.
Freaking hilarious! I laughed so hard reading this.
(No worries. I don't mind hijacking a thread I started in this case. It comes back full circle to what is influencing BMW and other auto makers.)
You mean why doesn't BMW give in to marketing and pay exorbitant fees to put Brembo brakes into its cars just so some BMW owners can turn to their Benz-driving friends and gloat that their BMW has Brembos? I really wish those who critique the stock "cheap" "inferior" brakes provide at least some quantifiable data (or even cogent qualitative criticism) of why the stock system is "inferior". Having used the stock brakes on track for repeated braking from over 160 mph, I can attest that the stock brakes are excellent even for such high-stress applications as the track, and certainly more than satisfy any street use . . . unless, of course, the criterion is "BREMBO" painted on one's calipers for the sake of having "BREMBO" painted on one's caliper.
MRichmond,
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 think Roman's point about brakes was simply to point out that they are not total trash on the track (with proper race pads, high temp fluid, perhaps Ti shims) as the rotors are large enough to handle the heat load cycle imposed on them. He definitely knows the pros of a high performance brake system. He likely feels like I do -- that 90% of the "reason" people want fixed caliper brakes is bling as they will never use or need such in their actual use of the vehicle.
From my standpoint, I would like a state of the art brake system (preferably Stoptech and not Brembo) also for a few reasons: feel/performance under heavy usage (having an extremely rigid caliper makes a huge difference in threshold modulation ability) and the ease of swapping out pads. Add to that a full floating, high performance rotor design (plug for Stoptech's internal cooling design here again) which is unlikely, unfortunately, to be installed on a car sold in USA by BMWNA -- sadly. They believe there are long-term potential issues with floating rotors for the "typical" M buyer likely based on their experience with E39 floating rotor design (which was poor) in Europe markets plus the fact they have to pay for maintenance here in the USA for 4 years.
__________________ Current stable:
2001 M5 LeMans Blue/Silverstone
Dinan: springs, Konis, rear sway bar, monoball bushings, and exhaust
Ground Control camber plates
Stoptech front brake kit
Brake ducts opened
TC Design brackets
OE 9.5" rear wheels all around & 275/35-18 Dunlop Direzza Sport Z1 Star Spec for street
275/35-18 BFG R1 & Nitto NT-01 R-comps for track
2003 330i ZHP 6MT Imola Red/Black Alcantara
2006 330i sport 6MT Electric Red/Black
2001 Audi S4 6MT Silver/sport Alcantara
1996 Volvo 850R wagon
When I awoke this morning I managed to get out of bed on the wrong side, (this is what happens when you work 15hr shifts 15 days straight on a Oil platform lol!) so may be I took it to heart to readally and came out all guns blazing lol!
I still stand by what I said and I also think Roman went to town on my post a bit harsh!
I agree if you put this type of brake system on a car just for show or kudos its wrong... but hey if the manufacture and more importantly the customer are willing to pay then good on them!
Again I only used Brembo was just a genaric name and will agree it was possible wrong to do so and agree there are other manufactures that have equal or even better products so no argument there. Also as you said most people doen't push their cars that hard BUT if you have a car thats capable of high speeds, rapid acceleration and marketed it as a 'motorsport' model and advertise it was and can be used on the track then you need to give it the where-with-all to do so... you could say the tyres which are speed rated at W are excessive because most people would not do 168mph or anywhere near it so they could get away with a lower speed rating.
Anyways I'm man enough to say sorry for my blunt and directed reply.
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.
Regards
Quote:
Originally Posted by ur20v
Anyways I'm man enough to say sorry for my blunt and directed reply.
My response, triggered by the "bling-seekers", also was unnecessarily blunt for which I apologize. I appreciate your desire for the best possible braking product. I am not aware of anyone documenting any braking deficiencies with the E60 M5. I am sure that the quality aftermarket suppliers such as Brembo, Stoptech, and AP offer better feel and modulation, if not better measurable performance. However, I don't think that the marginal improvements that will be appreciated by a tiny minority justify saddling the entire M5 customer base with significantly increased costs. The uneven pad wear is an issue in the stock, mono-piston design, but is easily and cheaply remedied (as Chuck mentions) by brass caliper guides which prevent twisting and the uneven wear. I incorporated the guides along with stainless steel brake lines to improve reliability and pedal feel. I never experienced uneven wear on track, regardless of whether I was using stock pads initially or when I started using the Pagid track pads. Since braking was an important issue for me, I consulted with a well-known braking expert whose business is selling brake upgrade kits (a Board sponsor). His advice was that the e60 M5 doesn't need such a kit because it, in effect, already has one. Finally, changing from Continentals, to PS2s, to Pilot Sport Cups made clear that tires are much more of a limiting factor on stopping than the brakes -- braking performance increased dramatically with the Cup tires, revealing that the brakes had plenty of bite that lesser tires could not use. So, my bottom line is that I have found the stock system -- combined with very inexpensive minor upgrades -- to be more than sufficient for track use. But, again, I wish there were more enthusiasts pushing BMW for better peforming components, so keep on keepin' on.
__________________
2006 M5 Silver Gray/Silverstone/Madeira Walnut
Dinan Stage 2 Suspension System
Supersprint Race exhaust with X-pipe
1998 M3 Coupe Technoviolet Track car
JRZ RS, Kirk roll bar, Racetech 4000W seats, GC sway bars, control arms, AA headers and 3" race exhaust (loud and proud), etc.
The Following User Says Thank You to MRichmond For This Useful Post:
The copper caliper 'guides' are they thin shims that fit between the pad and caliper as on the rubbing/support surface? Who makes these??
I agree with some if not all of your comments but really when we spend $100000 on a car the difference it would have made to fit a better brake system would have been $$$ or at worse $$$$ and I think we would have cought up no problem and save us doing the upgrades of shims/brake fluid/pads/stainless brake lines.
The copper caliper 'guides' are they thin shims that fit between the pad and caliper as on the rubbing/support surface? Who makes these??
The guides bolt directly into the caliper, perpendicular to the pad. I am trying to remember where I got mine. I think from Zeckhausen Racing (I know that's where I got the stainless steel lines), but I can't find them on his web site. Here are a couple of links to other sites with decent descriptions but for different models:
__________________
2006 M5 Silver Gray/Silverstone/Madeira Walnut
Dinan Stage 2 Suspension System
Supersprint Race exhaust with X-pipe
1998 M3 Coupe Technoviolet Track car
JRZ RS, Kirk roll bar, Racetech 4000W seats, GC sway bars, control arms, AA headers and 3" race exhaust (loud and proud), etc.
The Following User Says Thank You to MRichmond For This Useful Post:
I was referring to Ti shims/plates. You install these between the pad and the piston to increase the thermal resistance of the heat conduction path to the caliper and also shield the piston dust cover from "seeing" the hot back surface of the pad (from a radiation heat transfer perspective). They do a great job in protecting the dust covers and piston seals along with reducing the heat conducted into the piston, lowering piston temperatures (good for seals) along with lowering brake fluid temperatures.
You use Ti for the interstitial material since it has a low thermal conductivity for a metal. The shim/plate itself is actually very thin, so the thermal conductivity issue isn't great, but the Ti material does help. Again, the benefits you get from these are multi-fold: you introduce three thermal resistances to conduction between the pad and the piston (two thermal contact resistances plus the conduction resistance through the shim) plus you shield the very hot pad back surface from "seeing", from a radiation heat transfer standpoint, the dust cover and caliper (i.e. the back surface temperature of the Ti shim is now much less than the pad).
/thread highjack off
__________________ Current stable:
2001 M5 LeMans Blue/Silverstone
Dinan: springs, Konis, rear sway bar, monoball bushings, and exhaust
Ground Control camber plates
Stoptech front brake kit
Brake ducts opened
TC Design brackets
OE 9.5" rear wheels all around & 275/35-18 Dunlop Direzza Sport Z1 Star Spec for street
275/35-18 BFG R1 & Nitto NT-01 R-comps for track
2003 330i ZHP 6MT Imola Red/Black Alcantara
2006 330i sport 6MT Electric Red/Black
2001 Audi S4 6MT Silver/sport Alcantara
1996 Volvo 850R wagon
Linear Mode
