Evo tests the M6 and finds the brakes horrible (shocking!)

[lemming]

:lol:

it's the June 2005 issue, in case you were curious. here are some choice excerpts (they tested the car at the new Ascari track in Spain):

"....If the circuit tells us little about the chassis, it does expose the brakes. A perrenial M-car bugbear, they feel okay for a lap (although soon start to grumble), but by the end of the second the middle pedal feels worryingly long, and by halfway through the third, mechanical sympathy prompt you to back-off to avoid killing them completely."

"Quiz the M Division bods about this shortcoming and they prickle defensively, saying that the Ascari circuit doesn't allow much recovery time between corners, and that at the Nurburgring, with its longer straights and lack of chicanes the brakes are fin. All well and good if you only use the Nordschleife for your trackday kicks, but I reckon half a dozen laps of Bedford Autodromes's West circuit will reduce the M6's cross-drilled and vented discs to smoking jelly."

"Suggest that carbon-ceramic brakes, as fitted by Porsche, Ferrari and Mercedes are surely a more satisfactory solution and the prickling intensifies, followed by claims that carbon-ceramic discs are too expensive, generate too much heat and, for a car of the m6's bulk, would require 20in rims to accomodate discs of sufficient size."

"Mention that the similarly hefty Merc McLaren SLR manages to squeeze carbon-ceramic brakes behind 18in rims and you finally get a concesssion that there are some 'very interesting development cars being tested'. Great news for future M models, but a great shame for the M6, as it deserves brakes that are absolutely beyond reproach."


:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:


i believe i am on record as saying that BMW brakes are great....for the first few laps....and then suck pondwater loudly and vigorously after that --as we always point out, BMW needs to address its hubris and mount proper brakes. this is becoming such a trite joke.

[Jason C]

As I mentioned before, I found it interesting that a bunch of riced-out ecnoboxes have track-ready brakes (and forged wheels too) OEM for 1/2 the price, while BMW for all the "///Motorsport" chest-thumping they do remain stubbornly recalcitrant on this issue. :lol:

http://images.automotive.com/cob/factory_automotive/images/Features/auto_shows/2004_CIAS/2005_Subaru_Impreza_WRX%20STi_wheel%20and%20Brembo %20brakes.jpg

http://images.automotive.com/cob/factory_automotive/images/Features/auto_shows/2004_CIAS/2005_Mitsubishi_Lancer_Evolution%20MR_wheel%20and% 20Brembo%20brakes.jpg

http://www.transwheel.com/limages/BP73.jpg

:scratch:

[lemming]

the "M635" (e34) actually had 4 pot brakes.

[lemming]

CAR ran the m6 v. the 997S v. the arielatom.

while it's not surprise the arielatom (basically a hockey skate of a car) was much faster, they still chose the 997S as the best driver's coupe.

it's hard to think that someone is going to cross shop the m6 against the 997 and choose the m6.

subjectively the 911 has more cachet and quantitatively, the 997S (cheaper than the m6!!!!!!!!!!!!!!) is faster.

[The HACK]

It's the cooling, not the brake rotor size/caliper size that matters.

A friend has a 350Z track model that has the brembo brakes at Buttonwillow last year. He managed to boil his fluids badly and had to bleed inbetween sessions just to make the brakes work. My 350Z's rear brake completely disintegrated because the fronts were fading so badly, the rears needed to do a lot more work in order to keep slowing down the car.

The 350Z track had compound rotors and 4 pot brembo pistons on 12.8" rotors up front, yet the brake efficiency on the 350Z track was much less than my 323Ci with 328i size rotors. Why you ask? There's absolutely no cooling duct channeling air into the front brakes on the 350Z. All it's using is the centrifugal force of the rotor spinning to suck hot air out, and it's simply not efficient when the air surrounding the brakes are just as hot as the air inside the brake rotors and around the caliper.

And why do 'Chops have such great braking? It's not the compound, drilled, or ceramic rotors and massive calipers. It's their cooling duct. If you ever look at the underskirt of a 911, you will see various ground effects designed specifically to channel cool air from the front air dam directly to the rear of the rotor (no dust shield on those puppies) and blow cool air directly onto the caliper. All you need to have is the car be moving at all to get effective cooling into those brakes.

While you are singing the praises of the Carbon/Ceramic rotors fitted to exotics, you may want to check with some GT2/GT3 owners who opted for the Ceramic rotors AND tracked their cars. They FLAKED under heavy braking and needed to be replaced after every track weekend. That's a $1,000+ job just for each rotor ALONE.

Trust me, the BMW brakes are efficient enough. It's their brake cooling that needs to be worked on.

[lemming]

i am unsure if the bottom line is ducting, Hack, mostly because ducting is cheap relative to the fixed cost of multipiston brakes and it really sounds, from the responses of BMW NA people as well as engineers to be more about economics than design.

i had issues myself with added ducting and OEM brake calipers on a supercharged M coupe (aftermarket pads helped plus fluid) --but there was clear fade.

it's a shame that the M division has not addressed the brakes issue because all of their cars are really quite heavy. what will it take? a lot of accidents due to brake failure?

[The HACK]

i am unsure if the bottom line is ducting, Hack, mostly because ducting is cheap relative to the fixed cost of multipiston brakes and it really sounds, from the responses of BMW NA people as well as engineers to be more about economics than design.

i had issues myself with added ducting and OEM brake calipers on a supercharged M coupe (aftermarket pads helped plus fluid) --but there was clear fade.

it's a shame that the M division has not addressed the brakes issue because all of their cars are really quite heavy. what will it take? a lot of accidents due to brake failure?

Actually the issue here is exactly ducting, and how cheap BMW has become. Porsche (and any super-car, for that matter), designed their cars expecting some of their owners to take the car to the track. So they designed a brake and ducting system that will withstand repeated braking from high speed and not fade. BMW, on the other hand, when they designed the M series car, assumed that 99.9% of their owners will NEVER see a single track day (and they would be correct), and that those who DO take the car to the track, it is THEIR responsibility to find a way to keep those brakes cool. They (BMW) have basically washed their hands of the responsibility of building a track car for you, their first priority is to prevent water from getting into the brakes so the average driver won't go to brake on a rainy day, find nothing there, panic and crash their car and sue BMW.

But as far as a brake system is concerned, a sliding caliper design on a large compound/floating rotor is as efficient and cheaper to build than a multipiston, fixed caliper design. If you look at the specs, the BMW rotors are significantly larger than any of their supercar competitor. I believe the M6 rotors are 14"+?

Bottom line is, Porsche/Aston/Ferrari etc built cars to the highest standard, put in enough cooling to prevent fade on track. BMW built the brakes to the standard of average drivers on the street, and tries to limit their liability. That's why the E46 M3s come to the states with the cooling duct blocked off.

[FC]

The E55 AMG sedan has 8-piston calipers up front and 4-pistons calipers in the rear. I also believe it is cheaper than the M6.

[Nick M3]

The E55 AMG sedan has 8-piston calipers up front and 4-pistons calipers in the rear. I also believe it is cheaper than the M6.

Yes, but the brakes run on Windows and are prone to bluescreening. :p

[zach]

The E55 AMG sedan has 8-piston calipers up front and 4-pistons calipers in the rear. I also believe it is cheaper than the M6.

Yes, but the brakes run on Windows and are prone to bluescreening. :p

:lol: :lol:

[FC]

The E55 AMG sedan has 8-piston calipers up front and 4-pistons calipers in the rear. I also believe it is cheaper than the M6.

Yes, but the brakes run on Windows and are prone to bluescreening. :p

While true, that's another issue altogether. The hardware is there. They certainly didn't skimp on braking.

Still, the E55 doesn't the same performance pretenses that an M6 does. It's just a luxury performance sedan with a slushie.

[lemming]

i still disagree at the end of the day, Hack, because i've been on the track with an e36m3 and an e36/8, both with aftermarket ducting and the brakes were still marginal, and those were only 3000 pound cars. i was about the fastest in my run groups, too.

that's my experience. you have yours....from a 350Z. but do you from recent M cars? it's apples to oranges otherwise. M brakes are not much of an upgrade from standard 3 series running gear, but the cars are a lot faster.

[The HACK]

i still disagree at the end of the day, Hack, because i've been on the track with an e36m3 and an e36/8, both with aftermarket ducting and the brakes were still marginal, and those were only 3000 pound cars. i was about the fastest in my run groups, too.

that's my experience. you have yours....from a 350Z. but do you from recent M cars? it's apples to oranges otherwise. M brakes are not much of an upgrade from standard 3 series running gear, but the cars are a lot faster.

Brakes were marginal as in their stopping power, or brakes were marginal as in they fade like a steroid induced athlete weaned off the juice?

Marginal stopping power means 2 things: Sh*tty pads, or sh*tty tires. Fade means not enough cooling. If those E36 M3s were still fading with cooling ducts, it's indicative of a bigger problem than just brake cooling.

[lemming]

i still disagree at the end of the day, Hack, because i've been on the track with an e36m3 and an e36/8, both with aftermarket ducting and the brakes were still marginal, and those were only 3000 pound cars. i was about the fastest in my run groups, too.

that's my experience. you have yours....from a 350Z. but do you from recent M cars? it's apples to oranges otherwise. M brakes are not much of an upgrade from standard 3 series running gear, but the cars are a lot faster.

Brakes were marginal as in their stopping power, or brakes were marginal as in they fade like a steroid induced athlete weaned off the juice?

Marginal stopping power means 2 things: Sh*tty pads, or sh*tty tires. Fade means not enough cooling. If those E36 M3s were still fading with cooling ducts, it's indicative of a bigger problem than just brake cooling.

bridgerock s03's with track pads. and there was still fade in the later lapping sessions. ducting was not the issue on my cars. it did boil down to clamping force.

i have a pretty decent reference because i've had 993 brakes at the track and STi brakes at the track, also. both cars have phenomenal brakes. superior in feel as well as stopping power to any BMW brakes i've ever owned. c5 brakes are barely adequate, also, especially at the track. i have enough tracktime to be able to say that BMW brakes are barely adequate at the track in 3100 pound vehicles and that i have no idea why they have not addressed the issue in their heavier M vehicles.

i'm sure that stuka and nick M3 could weigh in on the issue, also as they have experienced the extreme speed the e46m3 can build --my guess is that both would be/are unthrilled with the OEM brake setup.

[nate]

Simply changing the pads would probalby alleviate many of the braking problems.

[The HACK]

i still disagree at the end of the day, Hack, because i've been on the track with an e36m3 and an e36/8, both with aftermarket ducting and the brakes were still marginal, and those were only 3000 pound cars. i was about the fastest in my run groups, too.

that's my experience. you have yours....from a 350Z. but do you from recent M cars? it's apples to oranges otherwise. M brakes are not much of an upgrade from standard 3 series running gear, but the cars are a lot faster.

Brakes were marginal as in their stopping power, or brakes were marginal as in they fade like a steroid induced athlete weaned off the juice?

Marginal stopping power means 2 things: Sh*tty pads, or sh*tty tires. Fade means not enough cooling. If those E36 M3s were still fading with cooling ducts, it's indicative of a bigger problem than just brake cooling.

bridgerock s03's with track pads. and there was still fade in the later lapping sessions. ducting was not the issue on my cars. it did boil down to clamping force.

i have a pretty decent reference because i've had 993 brakes at the track and STi brakes at the track, also. both cars have phenomenal brakes. superior in feel as well as stopping power to any BMW brakes i've ever owned. c5 brakes are barely adequate, also, especially at the track. i have enough tracktime to be able to say that BMW brakes are barely adequate at the track in 3100 pound vehicles and that i have no idea why they have not addressed the issue in their heavier M vehicles.

i'm sure that stuka and nick M3 could weigh in on the issue, also as they have experienced the extreme speed the e46m3 can build --my guess is that both would be/are unthrilled with the OEM brake setup.

Stuka may not agree with me, but he was never THAT fast in the M3. He's actually faster in the E30 325is. :) He's had more problem with pad wear than pad fade in the E46 M3.

Now, I've said Porsche design some of the most effective cooling systems for brakes in the market. I wouldn't be surprised if the 993 had superior braking. The WRX is somewhat of a surprise though. The C5 datapoint does bring up another interesting angle. The C5 also come equipped with 4 pot fixed calipers, if I'm not mistaken. Yet the brake feeling/fade problem still exist.

Which leads me back to my original point. It's not the brake system or how many pistons you have in a caliper, but how effectively you can cool the brake system that will determine how well the brakes will perform on the track. I would guess BMW still leaves it up to the consumer to properly duct their brakes or buy the right compound for track use.

[JST]

Simply changing the pads would probalby alleviate many of the braking problems.

Interestingly, C/D also drove the M6, presumably at the same track event. They noted in their article that BMW *did* fit special compound pads for the track, along with P Zero Corsas. They had no complaints about the braking; they praised the simplicity of a single piston system, given its effectivness.

Does Evo drive cars harder than C/D? I bet the answer to that is yes, though who knows?

[The HACK]

...along with P Zero Corsas.

BINGO. R-Comps have better grip, therefore repeated braking at the threshold will cause ANY brake system to overheat and fade. I'm sure if they had fitted R-Comps to the M6 competitors, you'd be at fade city too.

Not saying putting R-Comps will immediately cause fade, but it just pushes the threshold up that much higher. If the M6 was running with, say, Michelin PS2s then they probably won't be b*tchin' about how sh*tty the brakes are.

[lemming]

...along with P Zero Corsas.

BINGO. R-Comps have better grip, therefore repeated braking at the threshold will cause ANY brake system to overheat and fade. I'm sure if they had fitted R-Comps to the M6 competitors, you'd be at fade city too.

Not saying putting R-Comps will immediately cause fade, but it just pushes the threshold up that much higher. If the M6 was running with, say, Michelin PS2s then they probably won't be b*tchin' about how sh*tty the brakes are.

(sigh).

so many variables.

Automobile just arrived today and they duly noted that after 15 laps @ Ascari circuit, the tires were done --they (correctly) blamed the excessive weight as the culprit.

All in all, the reviews are okay for the car. but it boggles my mind why a 105k car has skimping on brake parts? and an 80k porsche with even less economies of scale can fit decent racing spec parts and engineering to bear on the problem?

i'd gladly pocket the 25k differential and buy another car and be happy in the 911S.

i'm really disappointed in the M6 effort, actually. let's be honest about this, there are many ways to arrive at an 8min nurburgring laptime. they already did it with the LeMans V12 X5, so it was not a stretch to see that they could do it with the m6 --but it's now priced at the level of an aston martin (but less exclusive) and is still outclassed at any enthusiast event by a run of the mill 997?

maybe i don't get it.

[Jason C]

maybe i don't get it.

You're not alone.