F80 M3 and F82 M4 Dyno and Weight: Comparison Time

[CanAutM3]

Originally Posted by swamp2

But again, the performance advantage is independent of anything about the car or engine, it is only about the shift being faster.

I do think that how much advantage the DCT provides is powertrain dependent. Tighter ratios on an engine such as the S65 can allow it to produce more average power over an acceleration run. On a 6MT, the benefit of the tighter ratios can be negated by the additional time needed to execute the shift; not the case with DCT.

Originally Posted by swamp2

My actual test results were not very conclusive, despite some care in the choice of the accelerometer and DAQ. There was some evidence in that data arguing for a truly zero shift time when it comes to simulation (in the S modes). There was also evidence for a drop in acceleration qualitatively like a MT shift.

Using 50 ms seems like a conservative approach (i.e. not to incredibly pro M-DCT, which I am). Now that being said the performance improvements in times to speed will only change by the difference in those shift times 50 ms to 0, i.e. 0.05 seconds which is insignificant.

Three 0.05s shifts is worth 0.15s to 100mph. Zero shift times for the DCT would put it on par with the 6MT to 100mph in this simulation.

[cws]

I don't think you can be underwhelmed by the car. However, the reviews I've read have said the DCT, adaptive and the ceramics are a must. You can build a $88K+ M3 when you fully option the car.

When you add all the little pieces to make the car more track specific you could easily be close to $95-$100K.

I don't see racing up 1500+ miles a month on this car being a good call for a "daily driver." Tracking the car will be a blast but are those Michelins going to last? Could be a $1500 weekend with brakes and tires.

You'll wish you bought this car when the next M3 is a turbo 4 cylinder.

[Sedan_Clan]

Originally Posted by cws

I don't see racing up 1500+ miles a month on this car being a good call for a "daily driver."

Why not? It's a mass produced car with loads of creature comforts meant to be driven daily. It isn't a no-compromise vehicle.

[NullCheck]

Originally Posted by cws

I don't think you can be underwhelmed by the car. However, the reviews I've read have said the DCT, adaptive and the ceramics are a must. You can build a $88K+ M3 when you fully option the car.

When you add all the little pieces to make the car more track specific you could easily be close to $95-$100K.

I don't see racing up 1500+ miles a month on this car being a good call for a "daily driver." Tracking the car will be a blast but are those Michelins going to last? Could be a $1500 weekend with brakes and tires.

You'll wish you bought this car when the next M3 is a turbo 4 cylinder.

Why do you need CCBs?

[Sedan_Clan]

Originally Posted by NullCheck

Why do you need CCBs?

He's just regurgitating info. CCB's are probably the most useless/unnecessarily option available for this car for 99% of its buyers.

[JoeFromPA]

Originally Posted by Sedan_Clan

He's badlyjust regurgitating info. CCB's are probably the most useless/unnecessarily option available for this car for 99% of its buyers.

Fixed that for you. He said you can make the car $95-100k trying to make it track-specific. (based upon the context, I don't think he meant "with aftermarket parts")

Seems like most reviewers to date didn't even get a chance to review the MT, and they are saying DCT is the way to go because it's a great transmission - not because the MT isn't.

Almost every reviewed car has CCBs. By all accounts, great brakes that are severely overpriced. How has every prior M3 been a trackable vehicle with "only" the stock steel brakes?

[Billj747]

Very cool comparison. Thanks for sharing all your hard work!

[Sedan_Clan]

Originally Posted by JoeFromPA

Fixed that for you. He said you can make the car $95-100k trying to make it track-specific. (based upon the context, I don't think he meant "with aftermarket parts")

Seems like most reviewers to date didn't even get a chance to review the MT, and they are saying DCT is the way to go because it's a great transmission - not because the MT isn't.

Almost every reviewed car has CCBs. By all accounts, great brakes that are severely overpriced. How has every prior M3 been a trackable vehicle with "only" the stock steel brakes?

Good point(s)! Thanks for articulating that. My fingers were tired. LOL!

[swamp2]

Originally Posted by CanAutM3

I do think that how much advantage the DCT provides is powertrain dependent. Tighter ratios on an engine such as the S65 can allow it to produce more average power over an acceleration run. On a 6MT, the benefit of the tighter ratios can be negated by the additional time needed to execute the shift; not the case with DCT.

It still sounds like you are confounding the issues. One needs to separate ratios vs. shift times and those effects are entirely separate. The engines character (i.e. shape of power/torque curves) is also entirely independent of shift time advantages.

Originally Posted by CanAutM3

Three 0.05s shifts is worth 0.15s to 100mph. Zero shift times for the DCT would put it on par with the 6MT to 100mph in this simulation.

True indeed but the big picture is more nuanced...

Time to speed and time to distance advantages from short shift times do not both follow the same pattern. Quicker shift times benefit time to speed much more cumulatively and earlier in the entire performance speed range. The savings in shift times do not add up linearly in time to distance, which is more important in an actual race (who is ahead). Thus 1/4 mi times for identical vehicles with differing shift times do not differ by shift time savings*number of shifts. Time to speeds will differ by this prediction. The reason for is due to basic math, acceleration profiles are very lumpy/complex, take the integral to get to velocity and the curves are smoothed, another integral and more smoothing. Acceleration dips significantly during a slow MT shift, velocity less so and distance even less.

That being said, overall effects are basically cumulative across the full spectrum of speeds. Devil is in the details...

[CanAutM3]

Originally Posted by swamp2

It still sounds like you are confounding the issues. One needs to separate ratios vs. shift times and those effects are entirely separate. The engines character (i.e. shape of power/torque curves) is also entirely independent of shift time advantages.

I am not confounding anything. The faster shift times of DCT are a benefit by themselves. But, the faster shift times of DCT can also allow the use of tighter ratios without the compromise seen on a MT. So they are not entirely separate.

Originally Posted by swamp2

True indeed but the big picture is more nuanced...

Time to speed and time to distance advantages from short shift times do not both follow the same pattern. Quicker shift times benefit time to speed much more cumulatively and earlier in the entire performance speed range. The savings in shift times do not add up linearly in time to distance, which is more important in an actual race (who is ahead). Thus 1/4 mi times for identical vehicles with differing shift times do not differ by shift time savings*number of shifts. Time to speeds will differ by this prediction. The reason for is due to basic math, acceleration profiles are very lumpy/complex, take the integral to get to velocity and the curves are smoothed, another integral and more smoothing. Acceleration dips significantly during a slow MT shift, velocity less so and distance even less.

That being said, overall effects are basically cumulative across the full spectrum of speeds. Devil is in the details...

Yes, this was fully understood . My point was focused on the 0-100mph number.

[tallshortguy]

Originally Posted by cws

I don't think you can be underwhelmed by the car. However, the reviews I've read have said the DCT, adaptive and the ceramics are a must. You can build a $88K+ M3 when you fully option the car.

When you add all the little pieces to make the car more track specific you could easily be close to $95-$100K.

I don't see racing up 1500+ miles a month on this car being a good call for a "daily driver." Tracking the car will be a blast but are those Michelins going to last? Could be a $1500 weekend with brakes and tires.

You'll wish you bought this car when the next M3 is a turbo 4 cylinder.

Uh the vast majority of reviews have praised the CCB's but mentioned that they are unnecessary unless you plan on tracking your car more than once in a while.

[cws]

CCBs are still an upgrade and better than steel discs. The Corvette ZRI came with Brembo CCBs standard BTW. If you don't want $8k+ brakes fine but if you want the best brakes possible than you buy the CCBs. I had PCCBs on my 2008 Porsche GT3 and they were amazing. Why would you leave off perhaps one of the best performance options you can have with the M3/M4? The car is blistering fast why would you not upgrade the brakes? Going fast is easy, stopping quickly and never wondering if you have brakes going 150+ mph is a good thing.

[swamp2]

Originally Posted by CanAutM3

I am not confounding anything. The faster shift times of DCT are a benefit by themselves. But, the faster shift times of DCT can also allow the use of tighter ratios without the compromise seen on a MT. So they are not entirely separate.

It still sounds like so to me.

Regardless of the presence of an overdrive gear like the current M-DCT has, one still needs to cover a give gear spread to match the cars fundamentals, power and drag primarily. A closer ratio across all gears is not not possible. Move one gear a bit closer and the next is further without another change, across the gears.

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.

[swamp2]

Originally Posted by cws

CCBs are still an upgrade and better than steel discs . The Corvette ZRI came with Brembo CCBs standard BTW. If you don't want $8k+ brakes fine but if you want the best brakes possible than you buy the CCBs. I had PCCBs on my 2008 Porsche GT3 and they were amazing. Why would you leave off perhaps one of the best performance options you can have with the M3/M4? The car is blistering fast why would you not upgrade the brakes? Going fast is easy, stopping quickly and never wondering if you have brakes going 150+ mph is a good thing.

This has been beat to death in a variety of prior threads. There has been no concrete benefit shown for the CSiC system in the new Ms and thus your statements above I put in bold are pure speculation.

[modkrazy]

Originally Posted by Needsdecaf

To each their own. I have seen both in the metal too, side by side, and it was a clear cut choice.

Damn, you probably like Coke over Pepsi don't you?

I'd have to side on the Coke side of this argument, too. Mineral white is too soft. So soft, it should come with a pack of M-branded tampons that fit conveniently in your purse.

[Needsdecaf]

Originally Posted by modkrazy

I'd have to side on the Coke side of this argument, too. Mineral white is too soft. So soft, it should come with a pack of M-branded tampons that fit conveniently in your purse.

That's Murse to you pal. Get it right at least.

Funny, I always thought that all the Alpine White cars should have the BMW Roundel replaced by a Maytag emblem.

[tom @ eas]

Had a chance to pull the Lithium battery from a F82 M4 over the weekend, quite a bit of weight was shaved off the previous AGM version:

Part: 61.21.9.312.759
Price: Not yet listed in system
Specs: 12V 69Ah 770A/860CCA

Lithium


Original


30lbs shed just from the battery alone.

System uses a different IBS connector and vent tube than the E9X M3, doubt a swap would be suitable for previous M3 models. However, the footprint is the same, keeping AGM/Lead Acid batteries an open possibility for budget-conscious as lithium type batteries can be $$.

[tom @ eas]

Originally Posted by dlbrooks18

Nice! Can you overlay stock E9X M3 dyno for comparison?

Sure thing, here's the F80 dyno from last week vs E92 M3 (both DCT):

[Buddy Revell]

Originally Posted by tom @ eas

Sure thing, here's the F80 dyno from last week vs E92 M3 (both DCT):

That's crazy for two engines that are rated only 11hp apart from the factory!!

[dlbrooks18]

^ WOW, thanks for posting!

[fusionchicken]

Originally Posted by tom @ eas

Sure thing, here's the F80 dyno from last week vs E92 M3 (both DCT):

Hate to re-quote images, but holy freaking delta batman, the difference between the torque curves especially is insane

[ersin]

Originally Posted by fusionchicken

Hate to re-quote images, but holy freaking delta batman, the difference between the torque curves especially is insane

Comparing the S55 to the S65 torque curve is like comparing Kate Upton to Paris Hilton.


Cheers.