Improviz

Actually, I'd prefer to use the actual torque/horsepower curve provided by BMW for the car if you don't mind. There is no dip like that to which you refer; as with all well-designed normally aspirated motors, there's a nice long rise, a peak, and a dropoff:


In fact, torque at 5,000 rpm is 95% of the maximum, meaning that 5,000 was a pretty damn GOOD starting point for the M, right in the meat of its powerband, which shows your assertion that it was not in its powerband to be just so much nonsense.

Stop whining and making excuses. The M went down.

skratch77

ok will use your dyno forget the mid tourqe dip that some dynos are showing.
your going to sit here and tell everyone that you think 5k is a good starting point for a race when the car is making 310hp or at 6k when its making 445hp

i proved my point and you still try to prove somthing when you have been proven wrong

go watch the video of an m5 that starts a race in first gear at 6.5k and see how well it does going all the way up to 6th

starting the m5 at 5k is like starting an s200 at 4k in a race right in the middle of its power band right.

i have proven that it was not in its power band and you come back with a data sheet dyno trying to say there is no dip.who cares the car makes almost 100 more hp 1200 rpm higher in the power band.

RennTechV12

What about the torque?

Torque = accleration.

I think it's funny how all you BMW guys want to talk about HP and not torque, let compare both!!

skratch77

hello look at the dyno impo posted.its peak tourqe is at 6k like where I said the car should of been in the first place

the m5 has more tourqe from 6k-7.5k than its does from 3k all the way to 5.5k

and ill repeat it again for my 3rd time the m5 was not in its power band.

RennTechV12

The M5 has 384 lb/ft of torque at max
The E55 has 516lb/ft of torque at max

both with very similar weight.

On what planet is 384 more than 516?

skratch77

we wernt compairing it to the e55.I was saying that the car was not in its power band.

on a side note an f1 car has 75ft lbs of tourqe and has no problem winning races

RennTechV12

Sorry, I'm so used to E55vsM5 comparisons.

Skratch..notice part of my quote was "similar weight" F1 cars weigh less than 2000lbs
and rev to over 14000rpms

skratch77

renn i know what you were trying to say I just had to bring up the f1 cars because you posted torque=acceleration

i wished th m5 had more low end grunt but thats the nature of its f1 style engine hi revves =hi acceleration

you have some crazzy cars man drive them like you stole em and let me get the gt if you ever get sick of it lol jk

enzom

The problem with the excuse is that the Gallardo kept pulling even after the M5 was well into its power band. If it were a five second race, then maybe you have a point.

RennTechV12

No problem. I personally think that the new M5 is ugly as hell, but I do respect it. It is definetly a performance car, there are different levels of performance. I think that the folks at BMW designed it to do exactly what it does, handle well on a road course and accelerate like a bat out of hell at high revs/speeds. I have a lot of respect for the BMW F1 team and Mworks division. I love low end torque and acceleration, and therefore I'm partial to the big displacement Benz motors.

There's enough room in this world for all of the elite cars (the M5/M6 definetly fit into this category) my motto is: don't compare...buy 'em all!

skratch77

once you get a 2 or 3 cl jump on the start of the race cars with pretty much equal numbers will be very hard for the m5 to catch up and rail it in.

the gall can go to 60 mph in first gear and from the looks of that video that car was in first and the m was not.

Improviz

Which just goes to show that you know nothing, and I mean absolutely NOTHING, about physics.

FORCE, i.e. TORQUE, is what moves the car, dummy. The force of the motor, translated through the drivetrain to the wheels, is what determines the acceleration at any given instance.

And when the max force, i.e. torque, of the motor is applied to the drivetrain IS when the vehicle will be producing its maximum acceleration.

See, troll, there are equations that govern this stuff. And you, obviously, don't know anything about them. But I do...and you're as wrong as you could possibly be.

You haven't proven a damn thing, chiefly because you're too ignorant of the physical principles involved to even make an attempt at mounting an effective argument.

From physics 101: force = mass*acceleration. Therefore, acceleration = force/mass. The accelerative force in this instance is the force produced by the motor, in Newton-meters, multiplied by the gearing and percent efficiency of the driveline, and divided by the wheel radius. From this you subtract the drag force on the car and frictional forces from the rolling resistance of the tires. You will then have the acceleration, in m/s^2, of the vehicle.

Now if you bother to read that little equation and have at least a rudimentary understanding of mathematics, you might instantly understand that instantaneous acceleration will be at its maximum when the force delivered to the wheels is at its highest, because the acceleration is *directly* proportional to the force, i.e. the torque, being applied to the drivetrain by the motor.

Which, fyi, occurs when the engine is operating at its torque peak.

Now in this case, at 5,000 rpm, the engine will be *right* in the meat of its power band: it will, from this point up, be producing above 95% of its peak accelerative force.

Still want to lecture me on Physics? Then I would suggest you read this first, and think twice. I know my stuff in this department, far far better than you even begin to understand it.

But what YOU said is that the engine is "out of its power band" at 5,000 rpm. And YOU were wrong. The engine is producing 95% of its peak torque at this speed. Meaning that it will be developing 95% of its peak acceleration.

And if that's not in the meat of the power band, what is? Do you even understand the meaning of the term "power band", or for that matter, what is meant by "band"?? Do you understand that an engine does NOT produce max power or torque for the width of its power band?

You haven't proven a bloody thing, except to show that you do not even understand the concept of force and its application in acceleration. Horsepower is the *rate* at which work is done; force is what accelerates the car.

Read a physics book and learn something before you go making yourself look stupid again.

VelocitE55

That was the biggest ownage I have seen here in a while!

MerzadY_BoY

haha

Falco

Let me simplify impro's point that you are clueless...by your argument the best place for the BMW to start the race is at 7750 rpm where hp is at its peak of 500 hp(anyone notice the dyno uses PF which is slightly different to hp/..) That is truly thinking...

Oh and i missing someting her but he dyno posted has torque=hp at ~4600 rpm when it should be 5252???

Falco

Let me simplify impro's point that you are clueless...by your argument the best place for the BMW to start the race is at 7750 rpm where hp is at its peak of 500 hp(anyone notice the dyno uses PF which is slightly different to hp/..) That is truly thinking...

Oh and i missing someting here but the dyno posted has torque=hp at ~4600 rpm when it should be 5252???

Falco

Let me simplify impro's point that you are clueless...by your argument the best place for the BMW to start the race is at 7750 rpm where hp is at its peak of 500 hp(anyone notice the dyno uses PF which is slightly different to hp/..) That is truly thinking...

Oh and am i missing someting here...the dyno posted has torque=hp at ~4600 rpm when it should be 5252???

reggid

Before people jump the gun consider the following. In order to get the highest possible instantaneous acceleration do the following:

If you want to do a rolling start from a specific speed its better to make as much hp as possible aka usually the lowest gear. This is despite having more torque at a lower rpm........i'll let you think about it.

If you want to do a rolling start from a specific gear it is better to start at the torque peak.....again i'll let you think about it.

This is fact!

btw skratch if you do a rolling run 1st gear at 7500rpm you'll be shifting so soon that you may lose a pit of time during the shift, so sometimes it may be good in theory but may not be practical even with a SMG

Mardeth

What about rpm? Your saying that it doesnt matter? E55s torque peak is between rougly 2k-4k, right? If thats so why doesnt the box change at ~4k for optimal performance?

chem0

bla bla bla all i hear is...
ITS THIS ONE THING OH OAHHH ITS THIS ONE THING~~

reggid

The actual torque of importance is that delivered the wheels which is can be expressed as a function of crank torque or crank hp.

Wheel Torque = Crank Torque x overall gear ratio = wheel hp / wheel Speed

so for the most wheel torque in any given gear you want the most crank torque or if you are starting from a roll at a given speed you want more wheel hp to give more wheel torque.

Really all you have to remember that at any speed you want to maximise your hp.

force = power / velocity

so if velocity is constant you get more force if you have more power.

(i have neglect inneficiencies to keep it a bit simpler)

reggid

you have more power >4k

Say you are travelling at 70mph in say 3rd gear with the engine operating its peak torque ~4k. Equivalently at 6k in 2nd gear you are travelling at the same speed (70mph). At 6k you have less crank torque than if you were at 4k in 3rd but the gear ratio is numerically higher so the fact that you have more power actually means your crank torque x gearing willl be higher.

As i said its always better to be making the most hp possible and not the most crank torque.

Beowulf

ignore list works wonders

anerbe

all these horsepower/torque comparisons have all been beaten down to a bloody pulp in every car forum. I suggest people just need to point to other threads or links to the basics of physics. I'm sure many of the users in a MB forum have taken physics class, and probably need just a quick link to a refresher. Also, not everybody is great at teaching the basics of physics.

On the internet, it seems everybody wants to be Mr. Moore from Head of the Class

on another note - Reggid and Improviz are correct in their theories - However the acceleration of a vehicle depends on too many variables to determine the faster car. Although technically, it could be figured out on paper, you need many different values not only in the engine characteristics and performance values, but all the characteristics of the drivetrain (friction, rotating mass, ratios, deflections, etc....)as well as weight of the car, traction capabilities, even resistance due to different alignment specs (toe and camber can vary this). There are too many measurements unknown to us that will allow us to predetermine the winner of similarly matched cars. That's why we still validate cars with road testing. Physics alone rarely accounts for every condition. This is also why on paper, car A should beat car B, but in the real world this doesn't necessarily apply.

skratch77

when did I say 7k

I said the car should of been at 6k.From there up every gear chang is in the power band.

just because its making 95% of its tourqe at 5k dosnt mean **** with this car.Its making 90% of its tourqe at 3k why not start there and use its whole tourqe band

you wanted proff that the car was not in its power band and i showed the video and told you to pause it.

e55 power with his car said that it feels the same in p500 or p400 all the way to 5.5k

go ahead and try and explain your physics on how a car that weighs 400lbs less has the same hp with a lower tourqe peak uses awd with long gears pulls 5cls on a car with better gearing faster shifting and higher tourqe peak in the power band.