BMWs (Finally) Get Brembo Brakes OEM...

[Emre]

Guys with Mitsubishi Evos and Subaru STi find them weak on a racetrack.

The problem is simply cooling, which is totally inadequate. No one complains about the calipers themselves.

Not to mention that the rubber dust boots are easy to melt, and that the aluminum calipers transmit heat to the brake fluid at lightning speed.

My dust boots were still fine after 4 years and 55K miles of street and moderately heavy track use. I overheated my calipers to the point where the red paint turned brown...yet the dust boots did not melt. BEesides, the rubber boots can always be replaced should the need arise.

I agree that there are better calipers on the market than Brembo F40's. But the Brembos are hardly garbage. And they're certainly much better than OEM BMW brakes...even those on M Cars.

Emre

[Emre]

Evos and STIs both have brake cooling issues because of their front driveshafts... there's no room for really effective ducts.

And because of their power.

Not because of their weight.

Despite that, Evo brakes are considerably better than the OEM E46 M3 brakes...a car that's heavier and more powerful in stock form. The E92 M3 is even heavier and more powerful. If there ever was a factory car that cried out for better brakes, it's the M3.

Emre

[matt]

Evos and STIs both have brake cooling issues because of their front driveshafts... there's no room for really effective ducts.

And because of their power.

Not because of their weight.


:mrgreen:

[Massive Lee]

I'd rather see AP racing make a factory/OEM kit. Brembo makes good stuff, but it's just so played out and there is better stuff out there.

I wouldn't trust either Brembo's F40 calipers on a track car. Those are street calipers. They are cheap but have great visual impact. I think that's where it ends. Guys with Mitsubishi Evos and Subaru STi find them weak on a racetrack. Not to mention that the rubber dust boots are easy to melt, and that the aluminum calipers transmit heat to the brake fluid at lightning speed.

I'd rather go with a race AP caliper, than what Brembo offers. Commonly. Brembo does have great products for racers, but not in the Gran Turismo range. Multiply the price of calipers by at leat two.

[CleanAzzE30z]

What does this mean for BMW-specific BBK manufacturers?

Also, now we can stop calling them "Porsche Big Red Calipers".

:)

thanks god, and for fucks sake its about time. How long has the brake issue been plaguing tracked BMWs???


Mariano

[Emre]

yes, he's not holding it constant because he's not relating it to the mass that's being moved, and why it's harder on the brakes (because of the power, not the mass).

The bottom line is:

(1) The E92 M3 has a curb weight of ~3700 lbs. To put things in perspective, my E30 track car weighs ~1100 lbs. less than this behemoth; my 400 hp Evo VIII weighs ~500 lbs. less and has bigger/better Brembo brakes.

(2) All the reviews from the E92 M3 press launch have stated that the brakes went away after just 2-3 laps, even though they were fitted with race pads. Reviewers from evo magazine experienced brake fade on the street.

That's the whole point. This car has inadequate brakes. Period. Brembo brakes will be a welcome upgrade.

Emre

[matt]

However, if the heavier car had a engine that allowed it to accelerate the same as the lighter car, the lighter car would still have a braking advantage, no? Are you saying that if you had a choice between at 2700lb 135 and 3000lb with a few more horsies, you would pick the latter? Basically, I think Erme's original point was that if you want a heavier car to be COMPETITIVE with a lighter one, it's going to require more stress on a lot of things, including the brakes.

It would be at a braking and cornering advantage. Lighter is better, pretty much all the time.

I think you guys are having a hard time with the relationship between mass and the amount of power required to move it. good job matt on your explanation!

Thanks.

[brandondan1]

no, it's an issue of semantics and what is being held constant. Matt is holding power constant. Emre is not. That is why they aren't seeing eye to eye.

Exactly. Neither of us were wrong. We were just debating about different factors.

[nando]

no, it's an issue of semantics and what is being held constant. Matt is holding power constant. Emre is not. That is why they aren't seeing eye to eye.

yes, he's not holding it constant because he's not relating it to the mass that's being moved, and why it's harder on the brakes (because of the power, not the mass).

I'm on your side here, damnit! :p

[FredK]

no, it's an issue of semantics and what is being held constant. Matt is holding power constant. Emre is not. That is why they aren't seeing eye to eye.

[nando]

I think you guys are having a hard time with the relationship between mass and the amount of power required to move it. good job matt on your explanation!

[uofom3]

I'd rather see AP racing make a factory/OEM kit. Brembo makes good stuff, but it's just so played out and there is better stuff out there.

[brandondan1]

That is exactly what I'm thinking, Emre. All he seemed to mention was that a bull doser takes more energy to move, and that's why it's harder to stop. That is a given, but why do you exclude mass when it is the exact thing that causes it to need excess energy in the first place? To me it just sounds like you're rewording it to fit your argument.

If a lighter car has more stopping power at its limit than a heavier car, then essentially, a lighter car could stop at the same rate as the heavier car using less braking force. Does stomping on the brakes not wear them out faster than pressing lighter?

I am looking from the same perspective as emre, but you seem to have added that the cars are no longer going the same speed which they wouldn't in a real world situation. I was basing everything I said earlier off of them going the same speed. The heavier car would have slower entry before the braking points, which would require less stress on the brakes to get it at optimal cornering speed...or not if the extra weight is in the wrong places and causes the car to need to go even slower. But this all equates to the car being slower anyway, so it's dumb to argue that heavier is better.

However, if the heavier car had a engine that allowed it to accelerate the same as the lighter car, the lighter car would still have a braking advantage, no? Are you saying that if you had a choice between at 2700lb 135 and 3000lb with a few more horsies, you would pick the latter? Basically, I think Erme's original point was that if you want a heavier car to be COMPETITIVE with a lighter one, it's going to require more stress on a lot of things, including the brakes.

[matt]

I was very precise with my terms:

On track, the weight of a car is irrelevant to how hard it is on brakes. High powered cars are hard on brakes.

A car on track, being a closed system, is a great example of the conservation of energy. No matter how heavy the car is, its brakes only need to dissapate as much energy as the engine can produce.

The question is: once both cars (heavier and lighter) are at a given speed, which one needs more force to stop?

That is obvious, and irrelevant to the statement I made.

Clearly, a heavier car going around the track at a higher speed will have greater demands on it's brakes. That's why they need to be bigger.

But a heavier car, with the same power (engine or motor) and the same driver: A) will not be going as fast B) will have the same demands on its brakes.

What exactly is your point?

My point is to educate the masses. Ignorance may be bliss, but knowlege is power.

[Emre]

In your example: Obviously car two would have more kinetic energy being heavier and having the save velocity... but where would it get that extra energy? It's motor!

I really don't understand the point you're trying so hard to make. Of course a car derives it's kinetic energy from its engine (or "motor" as you incorrectly call it). Where else would it come from?

Sure, a heavier car needs more power to reach the same speed as a lighter car. Duh. But that's not the question.

The question is: once both cars (heavier and lighter) are at a given speed, which one needs more force to stop?

Clearly, a heavier car going around the track at a higher speed will have greater demands on it's brakes. That's why they need to be bigger.

What exactly is your point?

Emre