Every BMW 3-Series Has 2,500 HP... In Its Brakes

[justagp]

A Toyota Camry takes only 16 more feet to stop from 70 mph at full throttle relative to closed throttle; and Infiniti G37 just 9 feet. Even a 540 hp Roush Mustang only takes an extra 80 feet.

See it all at http://www.caranddriver.com/features...tion-tech_dept

[Imola.ZHP]

Interesting, yet I'm not really sure how much market share a Luxury brand will steal from Toyota. From Lexus on the other hand, go get 'em!

[SE3P_to_E90]

over simplified statements make me smile

[blue2fire]

Meh, it notes that the Prius should have about the same. Leave it to this site to get excited about everything.

[fullrev]

Originally Posted by jaybird124

That's the point that needs to be taken into consideration. The problem has been you don't have vacuum assist at WOT (on any car). Then on top of that the Toyota's were having brake fade (which could happen on a 3, especially given the mighty M3's reputation for fade on the track). It's the comedy of errors that's producing the problems.

Not true.

Valvetronics vehicles have a vacuum pumps.

[yuny]

I agree with the last two posts. Our cars have similar braking power as a Prius. Awesome!!! Wait, what's the point of this article again? Oh right, it's to prove that BMW owners are complete suckers for exciting headlines that massage our egos.

[Z22Z]

Originally Posted by mr_nelson

excuse me if my question is dumb, but if your car accelerates out of control, cant you put the stick on neutral or put the automatic gear on N before braking???
just asking.. I dont know about that toyota story

From what I have heard the computer on the Toyotas wouldn't allow the car to go into neutral. However, if they were stick, they would not have that problem because the computer can't regulate the clutch.

[hubble bubble]

The car and driver article really makes you question the basic driving ability of anyone involved with the Toyota problems.

They took a Camry, a G37 and a 540hp supercharger Roush Mustang and tried braking from 70 and 100 mph, both without throttle and with the throttle floored. I EVERY case, the brakes overpowered the engine (Barely in the Roush at 100 mph). IN the Camry, at 70mph, there was only a 20 foot difference in stopping distance with and without the throttle. 20 feet!!!
http://www.caranddriver.com/features...tion-tech_dept

And that was without the #1 advice - shift into neutral.

[hubble bubble]

BTW - a friend had the same floormat issue in a Ford F350. He took it to the dealer and was told "yeah, that happens all the time with winter floor mats." But you never hear about Ford or others having the same issue?!?

[CarForHire]

Originally Posted by mr_nelson

excuse me if my question is dumb, but if your car accelerates out of control, cant you put the stick on neutral or put the automatic gear on N before braking???
just asking.. I dont know about that toyota story

You don't have to depress the clutch or brake to shift into neutral, whether it's a manual or automatic.

[JayRob]

good to know, def get what you pay for

[lamia2super]

idk my brakes dont feel that powerful

[JayKay335i]

Its just like a little kid running down the sidewalk and kicking a stranger in the junk. Except the little kid it BMW and the stranger is Toyota. Its just funny. They say in the original statement its just a joke.

[footie]

In response to Toyota's unintended acceleration debacle, BMW engineers decided to calculate the equivalent horsepower of a 3-series' brakes: roughly 2,500 HP. That's right, every 3-Series ships with more than twice the power of a Bugatti Veyron.

The engineers arrived at the 2,500 HP number after measuring the car's 60-0 MPH deceleration time (2.5 seconds), then calculating how much horsepower would be required to achieved equivalent acceleration (0-60 MPH in 2.5 seconds).

Nice article but I have a few questions about the accuracy.

Am I missing something here? How come they arrived at the figure of 2500hp, according to my reckoning the Bugatti Veyron achieves this very feat with only 1001hp, has VAG somehow bent the laws of physics when they developed the Veyron?

I wonder what weight they are used to calculate this result of 2500hp because it sure must be much more than what a 3 series actually weighs based on what the Veyron can actually achieve, maybe they factored in 1 second worth of wheelspin sitting stationary.

Sorry but it sounds like marketing BS to me.

[kulwin86]

good 1! that's also one of the reasons tht its good at doin burnouts!!! lol

[Imola.ZHP]

Originally Posted by hubble bubble

BTW - a friend had the same floormat issue in a Ford F350. He took it to the dealer and was told "yeah, that happens all the time with winter floor mats." But you never hear about Ford or others having the same issue?!?

Do some more homework friend, they tried to blame it on a floor-mat issue, its not a floor-mat issue, there is something seriously wrong with their cars...

That lady in a Lexus es350 put the car in nutral, reverse, etc, it wouldn't stop, and the brakes were of no help. I haven't done a lot of "homework" on it because I don't much care (no-one in my family has one of those cars), but from the little I've heard it seems as though the gas-pedals in some toyotas are now "wireless." This just spells disaster IMO, what if some crazy frequency interrupts that signal? Apparently gear selection has gone wireless as well or else you could just put the car in neutral and let the engine blow up. If the gas-pedal and gear selector are wireless, I would think the brake pedal would be too, which makes sense why they say the brake isn't "overriding" the "system," that same lady said she had every force in her body pressing on the brake with nothing happening in response...

Scarry, sure it might be cheaper to start making components in a car wireless, but some things just don't need to change...

Anyone with more knowledge on the issue feel free to correct me on anything I've got wrong. My point was just that its not just a simple floor-mat issue.

[JCbmw22]

When looking at the unintended acceleration like Toyota, BMW has already implemented a safety feature to counter act this from happening. If the cars accelerator is wot and you push the brake and hold it for more than a certain amount of seconds the cars computer will disengage the gas pedal.

[DBFIU]

There is a lot of confusion in this thread.

The original article for all practical purposes is correct. If you take a 3500 lb mass and accelerate it (negative acceleration is still acceleration) from 60 to 0 mph in 2.6 seconds, it will require X amount of power.

Stop thinking of POWER as shaft power. The brakes are 'creating' (moreso dissipating) this power in the form of heat.

You take a 3500 lbs car moving at some speed relative to the ground, now you want to stop it, convert all of that kinetic energy into thermal energy and you have hot brakes. If you take the temperature rise of the disks to be uniform assuming a Biot number less than 0.1, you can calculate the thermal power dissipated. I bet it would be close to 2500 HP in the kinetic energy calculation, crack open a heat transfer book and try it.

Try touching your brakes after youve just went from 60-0 in 2.6 seconds.

Also, someone mentioned that the rubber is the limiting factor of stopping distance. Yes that is correct, and in the test, the car had physically stopped from 60-0 in 2.6 seconds; so tire is now removed from the equation because we have hard data.

From an Engineering standpoint you can safely say that the MAJORITY of the stopping power is being produced by the brakes. Yes nature is helping you, friction of the road, friction of the air, engine friction, bearings etc... are a tiny amount of stopping power compared to all 4 brakes working.

The same cannot be said though for Formula cars who engine brake regularly because the friction of an engine spinning at 19,000 RPM is high enough to stop a car without need for braking, in some cases.

Anyway, the hard data is:

m = 3500 lbm
t = 2.6 s
a = ??
Power = ??

If you do the math 2500 HP is not hard to believe.

My 2 cents.

[footie]

^ Fair point, if you were to include the heat lose that the Veyron engine makes to produce those 1001 horses then I must conceed that it's over 2500hp in total. But the wording was not very clear for that very reason, it states more than twice a Veyron's output which is untrue and thus smells of marketing BS to me.

[DBFIU]

Originally Posted by footie

^ Fair point, if you were to include the heat lose that the Veyron engine makes to produce those 1001 horses then I must conceed that it's over 2500hp in total. But the wording was not very clear for that very reason, it states more than twice a Veyron's output which is untrue and thus smells of marketing BS to me.

Don't get me wrong, there is plenty of marketing BS in there...

[auggiem3]

Originally Posted by DBFIU

There is a lot of confusion in this thread.

The original article for all practical purposes is correct. If you take a 3500 lb mass and accelerate it (negative acceleration is still acceleration) from 60 to 0 mph in 2.6 seconds, it will require X amount of power.

Stop thinking of POWER as shaft power. The brakes are 'creating' (moreso dissipating) this power in the form of heat.

You take a 3500 lbs car moving at some speed relative to the ground, now you want to stop it, convert all of that kinetic energy into thermal energy and you have hot brakes. If you take the temperature rise of the disks to be uniform assuming a Biot number less than 0.1, you can calculate the thermal power dissipated. I bet it would be close to 2500 HP in the kinetic energy calculation, crack open a heat transfer book and try it.

Try touching your brakes after youve just went from 60-0 in 2.6 seconds.

Also, someone mentioned that the rubber is the limiting factor of stopping distance. Yes that is correct, and in the test, the car had physically stopped from 60-0 in 2.6 seconds; so tire is now removed from the equation because we have hard data.

From an Engineering standpoint you can safely say that the MAJORITY of the stopping power is being produced by the brakes. Yes nature is helping you, friction of the road, friction of the air, engine friction, bearings etc... are a tiny amount of stopping power compared to all 4 brakes working.

The same cannot be said though for Formula cars who engine brake regularly because the friction of an engine spinning at 19,000 RPM is high enough to stop a car without need for braking, in some cases.

Anyway, the hard data is:

m = 3500 lbm
t = 2.6 s
a = ??
Power = ??

If you do the math 2500 HP is not hard to believe.

My 2 cents.

Good post...thanks for the clarification

[33five]

nice find