Interview w/ M chief engineer Biermann hints at M3/M4 0-60 in 4.3 seconds and 26 MPG

[CanAutM3]

Originally Posted by basscadet

I have strong doubts of a an F80 M4 weighing less than a C7 Corvette.

+1

I also seriously doubt that the F8X will weigh less than a C7 Corvette...

[Sapper_M3]

Originally Posted by solstice

Remember, 1500kg for the M4 is EU Kerb weight without a driver. It will as you say very likely be +3500 lbs US Curb weight including driver. I think the Vette has a sub 3300 lbs US Curb weight.

Unfortunately, this isn't the case with the vette's weight: Car & Driver weighed it at 3450 lbs; they even note in the article that it was a much heavier car than they expected.

As for the M3/M4 we can only speculate right now, but BMW up to now is promising us 250 lbs off the weight of a similarly optioned E9X M3. My E92 weighed on certified scales with 1/2 tank of gas (no driver) weighs 3550 lbs, and I'm nearly fully loaded (no DCT or sound system). 250 lbs off gives is a 3300 lb curb weight.

I'm not saying we'll actually see this, of course, but we can still hope. At any rate, 3400 lbs curb weight seems likely, and that is STILL less than the new vette.

[Sapper_M3]

Originally Posted by ersin

Engine torque means nothing for performance. The number that completely trumps peak engine torque is hp to weight ratio. If you want to bring torque into the equation it has to be wheel torque where you take into consideration gearing.

Also note that the single engine torque figure is the peak torque number only at the engine speed (rpm) that gives this figure. At all other rpms the torque is lower depending on the torque curve. For performance you want the engine torque to keep this peak for as wide a range as possible, that is the torque times the range of rpm that it works over, or as they put it, the area under the torque curve. All torque curves are different for different engines and you would need calculus or a computer to figure out the real engine potential. And this can be done if you get the torque figures for the whole rpm range. However, as it turns out, the maximum horsepower IS the area under the torque curve. And this is why horsepower is the more meaningful number.

So, let me repeat this: a single, maximum torque number for an engine in a specific car alone is meaningless as an indication of performance. Horsepower has more meaning in this context and horsepower per weight happens to be one of the best single number indicators of acceleration and speed.


Cheers.

This. I wish everyone on this forum would read this. Peak Power is a fairly meaningful figure to quote without any other knowledge of a car. For one thing, peak power to weight has meaningful and accurate performance correlations.

Peak torque on the other hand means very little because of the effect of gearing. Peak torque to weight means little to nothing, and a peak torque value even with the gearing ratios is fairly meaningless without the torque curve.

[Boss330]

Originally Posted by ersin

Engine torque means nothing for performance. The number that completely trumps peak engine torque is hp to weight ratio. If you want to bring torque into the equation it has to be wheel torque where you take into consideration gearing.

Also note that the single engine torque figure is the peak torque number only at the engine speed (rpm) that gives this figure. At all other rpms the torque is lower depending on the torque curve. For performance you want the engine torque to keep this peak for as wide a range as possible, that is the torque times the range of rpm that it works over, or as they put it, the area under the torque curve. All torque curves are different for different engines and you would need calculus or a computer to figure out the real engine potential. And this can be done if you get the torque figures for the whole rpm range. However, as it turns out, the maximum horsepower IS the area under the torque curve. And this is why horsepower is the more meaningful number.

So, let me repeat this: a single, maximum torque number for an engine in a specific car alone is meaningless as an indication of performance. Horsepower has more meaning in this context and horsepower per weight happens to be one of the best single number indicators of acceleration and speed.


Cheers.

Originally Posted by Sapper_M3

This. I wish everyone on this forum would read this. Peak Power is a fairly meaningful figure to quote without any other knowledge of a car. For one thing, peak power to weight has meaningful and accurate performance correlations.

Peak torque on the other hand means very little because of the effect of gearing. Peak torque to weight means little to nothing, and a peak torque value even with the gearing ratios is fairly meaningless without the torque curve.

"Thanks" for quoting my post completely out of context...

If you read my entire post you both can see that I emphasize the power to weight ratio when I argue that the M3/M4 should be close. As an afterthought I mention that the Stingray has more torque than the M3/M4 (you might misunderstand that and I see that it could have been excluded from the post, to avoid that confusion. But I just thought that some fact wouldn't be wrong, seeing that we discussed the power and weight of two cars, why not just mention their respective torque figures as well?).

And, didn't you know that we DO know the torque curve of the S55?

In this post we have both the power/torque chart and a statement on the rev range the S55 have peak power and peak torque.

http://f80.bimmerpost.com/forums/sho...d.php?t=892746

Peak torque is delivered from "under 2000 RPM to over 5000 RPM" and peak power is delivered "from 5000 RPM to 7300 RPM"

[CanAutM3]

Originally Posted by Sapper_M3

BMW up to now is promising us 250 lbs off the weight of a similarly optioned E9X M3.

Where did you get that number from?

All I have read so far is BMW quoting 80kg (175lbs) less than a similarly equipped E92...

Originally Posted by Sapper_M3

My E92 weighed on certified scales with 1/2 tank of gas (no driver) weighs 3550 lbs, and I'm nearly fully loaded (no DCT or sound system). 250 lbs off gives is a 3300 lb curb weight.

When I weighed my well optioned M3 (DCT, Nav, premium sound, CF roof) with a full tank, it came to 3688 lbs. Our numbers line up pretty well: 3550lb + 45lb (DCT) + 50lbs (½ tank of fuel) = 3645 (33lb variance).

[CanAutM3]

Originally Posted by ersin

Engine torque means nothing for performance. The number that completely trumps peak engine torque is hp to weight ratio. If you want to bring torque into the equation it has to be wheel torque where you take into consideration gearing.

Also note that the single engine torque figure is the peak torque number only at the engine speed (rpm) that gives this figure. At all other rpms the torque is lower depending on the torque curve. For performance you want the engine torque to keep this peak for as wide a range as possible, that is the torque times the range of rpm that it works over, or as they put it, the area under the torque curve. All torque curves are different for different engines and you would need calculus or a computer to figure out the real engine potential. And this can be done if you get the torque figures for the whole rpm range. However, as it turns out, the maximum horsepower IS the area under the torque curve. And this is why horsepower is the more meaningful number.

So, let me repeat this: a single, maximum torque number for an engine in a specific car alone is meaningless as an indication of performance. Horsepower has more meaning in this context and horsepower per weight happens to be one of the best single number indicators of acceleration and speed.


Cheers.

Your post is mostly correct, except for the fact that power in NOT the area under the torque curve. It represent the potential of the torque value at a single RPM point and in no way considers the shape of the rest of the torque curve.

[Boss330]

Originally Posted by basscadet

No, I am having difficulty believing that the M3/M4 will be anywhere close to 3300lbs. I would wager a large sum of money that it will weigh no less than 3550lbs as commonly optioned in the US market.

If you have ever seen a C7 up close you will realize it is a much smaller car than a BMW 3 series car. It's not Lotus-small but almost.

The Stingray is just under 4" (10cm) shorter wheelbase, roughly 5" (12cm) shorter overall length and just over 2,5" (6,6cm) wider than the F30 3-series. It's not a huge difference, even though it might appear so due to the different design.

If we will see the promised weights on the M3 is another matter, but given BMW's stated DIN weight of under 1500kg in base version (just as the Stingray's weight also is quoted for a base version) the M3 shouldnt lag far behind the Stingray...

[Boss330]

Originally Posted by swanson

BMW quotes dry weight, meaning no fluids. I bet the M3/M4 weighs more like 34XXlbs

Do you mean that BMW states dry weight in general or just in this case?

BMW's official weights (in brochures etc) are stated per EU legislation with driver and 90% fuel and fluids.

The Sport Auto article mentioned that the 1500kg weight was according to DIN. If it's DIN 70020, then that also includes fuel, driver and fluids.

http://de.wikipedia.org/wiki/Leergewicht

Before 2006 there was also a DIN norm that operated with "dry weight", but from 2005 all type approved vehicles have a curb weight consisting of vehicle, including a full tank of fuel (in the German system, 90% according to EU), driver, tool kit, warning triangle and spare tire (when fitted).

The stated curb weight for the E92 M3 is 1580kg and 1500kg is a 80kg save over the E92 M3, so it seems like the 1500kg weight should be fairly accurate... Especially when we take into account the weights provided above and that the officially quoted weights is the bare bones base version.

How many 1500kg M3/M4 that actually will be sold is a different matter though... Most will have some options that add weight.

[fuddman]

Like the MPG!
Now if they just make the tank bigger...

[Sapper_M3]

Originally Posted by CanAutM3

Your post is mostly correct, except for the fact that power in NOT the area under the torque curve. It represent the potential of the torque value at a single RPM point and in no way considers the shape of the rest of the torque curve.

You make a fair--and accurate--distinction, but ersin wasn't "wrong," although his terminology could have been more qualified: AVERAGE POWER is the area under the torque curve.

[Sapper_M3]

Originally Posted by Boss330

"Thanks" for quoting my post completely out of context...

If you read my entire post you both can see that I emphasize the power to weight ratio when I argue that the M3/M4 should be close. As an afterthought I mention that the Stingray has more torque than the M3/M4 (you might misunderstand that and I see that it could have been excluded from the post, to avoid that confusion. But I just thought that some fact wouldn't be wrong, seeing that we discussed the power and weight of two cars, why not just mention their respective torque figures as well?).

And, didn't you know that we DO know the torque curve of the S55?

In this post we have both the power/torque chart and a statement on the rev range the S55 have peak power and peak torque.

http://f80.bimmerpost.com/forums/sho...d.php?t=892746

Peak torque is delivered from "under 2000 RPM to over 5000 RPM" and peak power is delivered "from 5000 RPM to 7300 RPM"

Boss330--fair enough; to be honest, I hadn't even read your post. I just piled onto the--still correct, although with misplaced anger if it was directed at you--good post that ersin had made.

And yes, I know we have the torque curve now for the S55. That makes it even more egregious when people blindly compare peak torque figures between the stingray and the new M3/M4. The information is out there, but we don't use it because quoting peak torque is much easier (and more easily communicable) than looking over curves. Unfortunately, alone it doesn't really mean a significant amount.

[Sapper_M3]

Originally Posted by CanAutM3

Where did you get that number from?

All I have read so far is BMW quoting 80kg (175lbs) less than a similarly equipped E92...



When I weighed my well optioned M3 (DCT, Nav, premium sound, CF roof) with a full tank, it came to 3688 lbs. Our numbers line up pretty well: 3550lb + 45lb (DCT) + 50lbs (½ tank of fuel) = 3645 (33lb variance).

I was working off this article (I'm posting the link from Edmunds.com, but I doubt they wrote it, because I've seen a nearly identical article from numerous other sources):

"The lightest version of the new cars will weigh less than 3,307 pounds...."
From: http://www.edmunds.com/car-news/2014...-revealed.html

So, to be fair, I was really working off my assumption that the lightest E92 M3's were about 3550 lbs, and this "3307 lb' quoted figure chopped off about 250 lbs. My article is also 2 months old now; is there a new "best reference" on expected weight for this thing? I always prefer to see them actually quoting curb weight versus simply telling us "XXX" lbs lighter, since that just leads us all to argue about how much the E9X M3 weighed.

And yeah, looks like our weights agree. I'm about to make a major move across country, so I'll be weighing my car empty and loaded (with house items; work compensates me to an extent for the move) on certified scales again. I'll be interested to see if there's any significant variance between my previous weighing (on certified scales) and this weighing.

[Sapper_M3]

Originally Posted by basscadet

No, I am having difficulty believing that the M3/M4 will be anywhere close to 3300lbs. I would wager a large sum of money that it will weigh no less than 3550lbs as commonly optioned in the US market.

If you have ever seen a C7 up close you will realize it is a much smaller car than a BMW 3 series car. It's not Lotus-small but almost.

Fair enough--and for the final word on that, I guess we play the waiting game.

I won't say I'm optimistic that the production car is down to their quoted curb weight estimates, but if they've been ANYWHERE close to being honest, we should see a car that meets or beats the new corvette's 3450 lbs. As for me, I'm still waiting on reviews, but I won't be a strong potential buyer if this thing doesn't weigh somewhere near the "less than 3307 pounds" talk for the lightest optioning of the car.

[CanAutM3]

Originally Posted by Sapper_M3

You make a fair--and accurate--distinction, but ersin wasn't "wrong," although his terminology could have been more qualified: AVERAGE POWER is the area under the torque curve.

Ersin did say that

Originally Posted by ersin

the maximum horsepower IS the area under the torque curve.

So he is wrong

Further, even saying "average power is the area under the torque curve" is not true...

[Sapper_M3]

Originally Posted by CanAutM3

Agreed about "average power" .

However, ersin did say that

So he is wrong

Damn, good catch! I missed that.

[CanAutM3]

Originally Posted by Sapper_M3

Damn, good catch! I missed that.

Thinking about it more, even saying "average power is the area under the torque curve" is not true....

[Sapper_M3]

Originally Posted by CanAutM3

Thinking about it more, even average power is not true....

...but it is.

EDIT: Doing more research now, and I'm beginning to question if everything I know is wrong. Just a quick search led me to this power point presentation (haven't vetted the source yet): http://www.tazcobra.com/torque.pdf
Is the area under the torque curve only a good approximation of average power..?

[CanAutM3]

Originally Posted by Sapper_M3

...but it is.

Think about it...

Calculate the area under the curve between 7000 and 8000 RPM of an engine that makes 250lb-ft in that range:

(8000-7000) x 250 / 5252 = 48 avg hp

In reality, it makes

(7000x250/5252 + 8000x250/5252)/2 = 357 avg hp

[Someone?]

4.3= 0 to 60 isn't very good at considering or current M3 can do that, and the M4 should make more power A Lot more torque and is lighter.

[duk]

26mpg highway? not bad... prob 21-22 combined then.

[e39>all]

The 0-60 time will be as good as the m5's. BMW simply will not list a lesser model's performance better or equal to their flagship models that cost much more. Also, I would wager the actual power of the new m3/4 is at least 450hp, and around 400 ft lbs torque.

[basscadet]

Originally Posted by duk

26mpg highway? not bad... prob 21-22 combined then.

I am hoping that figure is mixed, not highway.

An e92 335i riding on slightly narrower tires can get 30mpg highway easily. With fatter tires and probably more efficient engine, I think 30mpg hwy should be attainable.