F80 M3 and F82 M4 Dyno and Weight: Comparison Time

[JoeFromPA]

That dyno is showing 150 pound peak difference in torque TO THE WHEELS as well as 51 peak whp difference.

That's not "oh it's slightly faster" - that's an enormous power difference between the two. Wow.

[Sedan_Clan]

Originally Posted by JoeFromPA

That dyno is showing 150 pound peak difference in torque TO THE WHEELS as well as 51 peak whp difference.

That's not "oh it's slightly faster" - that's an enormous power difference between the two. Wow.

....but the S65 sounds so good though, and it revs to 8200 RPM.

[GregW / Oregon]

Originally Posted by Sedan_Clan

....but the S65 sounds so good though, and it revs to 8200 RPM.

Uhh, 8,400 (at least my '08).

[Sedan_Clan]

Originally Posted by GregW / Oregon

Uhh, 8,400 (at leat my '08).

Damn, BMW cut me out of 200 RPM's. It's BuyBack time!

[gthal]

Originally Posted by Sedan_Clan

....but the S65 sounds so good though, and it revs to 8200 RPM.

In all seriousness, the area under the F8X curve is WAY, WAY, WAY more than the E9X. The power/torque is barely comparable... and the car is lighter by at least a little

[Sedan_Clan]

Originally Posted by gthal

In all seriousness, the area under the F8X curve is WAY, WAY, WAY more than the E9X. The power/torque is barely comparable... and the car is lighter by at least a little

Gotta love that somebody gets the humor. So tense in these parts lately.

...but yeah, the differential is significant. At least the bigger picture is understood by most. The performance delta is vast between these two cars.

[swamp2]

Originally Posted by tom @ eas

...30lbs shed just from the battery alone. ...

Awesome that is the entire weight savings between the new and old cars...

[gthal]

Originally Posted by Sedan_Clan

Gotta love that somebody gets the humor. So tense in these parts lately.

...but yeah, the differential is significant. At least the bigger picture is understood by most. The performance delta is vast between these two cars.

The more I look at that dyno, the more it amazes me... 125 HP and torque difference at 5,250 RPM to the wheels between the cars. Holy shit... that is a LOT.

[Sedan_Clan]

Originally Posted by swamp2

Awesome that is the entire weight savings between the new and old cars...

HE LAUGHS!!!!!!!! HE SMILES!!!!!

Damn it swamp2, I knew you had it on you!

[swamp2]

Originally Posted by Sedan_Clan

HE LAUGHS!!!!!!!! HE SMILES!!!!!

Damn it swamp2, I knew you had it on you!

At least I gave the friendly/sarcastic smiley and I meant it. The battery is just one part of a much larger weight (and intertia) control strategy that was quite effective especially given this is a larger car than the E9X. I just wish BMW hadn't spoiled us with the 80 kg lighter nonsense...

[Sedan_Clan]

Originally Posted by swamp2

At least I gave the friendly/sarcastic smiley and I meant it. The battery is just one part of a much larger weight (and intertia) control strategy that was quite effective especially given this is a larger car than the E9X. I just wish BMW hadn't spoiled us with the 80 kg lighter nonsense...

We need more friendly/sarcastic smileys from you. We, the fans, demand more damn it. Just poking at'cha man.

[BadBoostedBMWM3]

Wow!

Thank you for contribution. So, ~30 degrees in IATs equates to ~30whp... That was more than expected. These cars need some water injection or meth/water to maintain temps.

Also, how large are the fuel tanks? To calculate weight difference.


I do like the modified stance.

[swamp2]

Originally Posted by BadBoostedBMWM3

Also, how large are the fuel tanks? To calculate weight difference.

60 liters, but unsure if that counts the reserve volume.

[CanAutM3]

Originally Posted by JoeFromPA

That dyno is showing 150 pound peak difference in torque TO THE WHEELS as well as 51 peak whp difference.

That's not "oh it's slightly faster" - that's an enormous power difference between the two. Wow.

At the risk of repeating myself, that "wheel torque" number shown on chassis dyno charts is a fictive number that does not exist in real life.

You either have wheel torque that is engine torque multiplied by the final drive and gear ratios minus drivetrain losses, or you have engine torque without drivetrain losses. Not a mix of both.

That ~50hp increase over a broad RPM band is what really matters.

[CanAutM3]

Originally Posted by swamp2

60 liters, but unsure if that counts the reserve volume.

My understanding is that BMW usually includes the reserve in the total tank capacity

[Sedan_Clan]

Originally Posted by CanAutM3

My understanding is that BMW usually includes the reserve in the total tank capacity

I believe this is true. When I've filled up right around 0 miles on the dash, it amounted to around +/-15.5 gallons. When I've driven 14-15 miles on "---", it takes the total 16.4 gallons or whatever it is.

[CanAutM3]

Originally Posted by swamp2

Perhaps you mean the situation in mind of the benefits of an additional gear? If the additional gear is not used for an over drive type gear then this truly allows tighter spacing across all of the gears with no penalty that would normally be present from the time to shift the MT.

In this regards DCT can leverage extra gears by not have the normal penalty of a higher quantity of slower shift times as compared to a MT with the same number of gears.

That's it

Note that a 6MT E9X M3 does not need redline in 6th to achieve top speed. Tighter ratios can be had without compromising top speed, but it would be at the expense of fuel economy. That is where the additional gear comes in handy.

[CanAutM3]

Originally Posted by Sedan_Clan

I believe this is true. When I've filled up right around 0 miles on the dash, it amounted to around +/-15.5 gallons. When I've driven 14-15 miles on "---", it takes the total 16.4 gallons or whatever it is.

I had a similar experience where I had to really stretch one tank (not happy or proud about it ) and ended up putting 62.2 liters to fill her back up.

[Sedan_Clan]

Originally Posted by CanAutM3

I had a similar experience where I had to really stretch one tank (not happy or proud about it ) and ended up putting 62.2 liters to fill her back up.

At least you didn't sip your final tablespoon of gas while waiting in a McDonald's drive thru for a bacon & egg biscuit on a rainy morning, and need the help of 4 Hispanic dudes to push your M3 into a parking spot (..while the gf brought you a gallon of gas). So funny and embarrassing.

[jc05e46m3]

Originally Posted by CanAutM3

At the risk of repeating myself, that "wheel torque" number shown on chassis dyno charts is a fictive number that does not exist in real life.

You either have wheel torque that is engine torque multiplied by the final drive and gear ratios minus drivetrain losses, or you have engine torque without drivetrain losses. Not a mix of both.

That ~50hp increase over a broad RPM band is what really matters.

I would like to suggest that even is the wheel torque is "ficticious", it's still a number that can be used to compare gains/differences between different vehicles. Sure, not all vehicles will have the same losses, but I think the Wtq number is still a good data point to have.

[CanAutM3]

Originally Posted by jc05e46m3

I would like to suggest that even is the wheel torque is "ficticious", it's still a number that can be used to compare gains/differences between different vehicles. Sure, not all vehicles will have the same losses, but I think the Wtq number is still a good data point to have.

Nope, "Wtq" as a single number is utterly useless.

I agree that looking at the shape of the "Wtq" curve can give an idea of the character of an engine. But one cannot compare different vehicles' performance relative to each other looking at "Wtq" curves only.

[JoeFromPA]

CanAutM3 -

If the wheel hp is solid, and the calculation of wheel torque is a fixed calculation, then while it may be a fictitious reference it is a consistent reference that is comparable across models, correct?