[razman]

According to these guys, the base and comp trims put out only an 8 max hp difference. Having ordered the base, that obviously sounds like good news but it seems too good to be true given BMW claims there's a 30 hp difference. Is anyone aware of other similar tests that can verify or refute their claims?

[NightWriter]

I haven't driven the manual yet, but numerous reviews and track tests suggest the torque differences (and butt dynos) between the two are not trivial.

Are these numbers adjusted for drivetrain losses? Because if those are the raw numbers at the wheels, that's incredible.

[kjx]

It's the torque difference that matters because that's what affects the transmission the most. It is also what most affects acceleration at lower speeds.

Power matters when you've hit higher speeds and is what limits performance and acceleration there.

The amount of load in gear shifts between higher gears at higher speeds is relatively far lesser than say the load shifting from the first to second gear at wide open throttle.

So from a mechanical perspective, to protect the transmission, BMW likely has to limit the peak torque in the MT more significantly vs. peak power relative to the competition.

Also, for any car, peak power and peak torque don't tell the full story of how it may be expected to perform at WOT. In the end, it's actual real world measurements of how fast it hits 60 mph, 100 mph and so on that matters. In perfect conditions, in the wet, etc. How fast and confidently can it corner, brake, etc. How communicative is the steering and chassis. Peak power and torque are vanity metrics that only hint at what may be possible in what really matters.

[razman]

Originally Posted by NightWriter

I haven't driven the manual yet, but numerous reviews and track tests suggest the torque differences (and butt dynos) between the two are not trivial.

Are these numbers adjusted for drivetrain losses? Because if those are the raw numbers at the wheels, that's incredible.

Yes, they've been adjusted for drivetrain losses.

[razman]

Originally Posted by kjx

It's the torque difference that matters because that's what affects the transmission the most. It is also what most affects acceleration at lower speeds.

Power matters when you've hit higher speeds and is what limits performance and acceleration there.

The amount of load in gear shifts between higher gears at higher speeds is relatively far lesser than say the load shifting from the first to second gear at wide open throttle.

So from a mechanical perspective, to protect the transmission, BMW likely has to limit the peak torque in the MT more significantly vs. peak power relative to the competition.

Also, for any car, peak power and peak torque don't tell the full story of how it may be expected to perform at WOT. In the end, it's actual real world measurements of how fast it hits 60 mph, 100 mph and so on that matters. In perfect conditions, in the wet, etc. How fast and confidently can it corner, brake, etc. How communicative is the steering and chassis. Peak power and torque are vanity metrics that only hint at what may be possible in what really matters.

Agree with all of this. Just odd that BMW would tout the max HP difference between the two at 30 hp, if it's far less. I suppose it's marketing.

[bri1042]

Torque and Horsepower are not two different attributes of an engine. Torque is a "timeless" measurement of force, not the amount of work being done. RPM's add the "time" factor (how many times per second is that force being applied). Horsepower is our goofy name for the measurement of work being done. More torque at low RPM's means more Horsepower at low RPM's. More Horsepower means more work being done resulting in acceleration.

HP=TQ*RPM/5252. Acceleration is always about the amount of work being accomplished by your engine vs. the drivetrain losses, air resistance, weight, inertia, etc...

(vastly simplified)

[Scorp!on]

Having driven Base (which I own), Comp and also XDRIVE I can tell you that you feel the difference, quiet a lot actually.

Does it bother me?
It did initially, but you get used to every power so who the hell cares.
I have MT which makes it much more engaging and therefore a lot more fun (for me).
I still have the option to get this torque difference with a tune, which I eventually will as soon as the warranty is through.

[kDot17]

The few of us actually buying manuals are getting them for the engaging driving experience, not the power! However a little more than advertised is still nice

[TJR_///M3]

Originally Posted by bri1042

Torque and Horsepower are not two different attributes of an engine. Torque is a "timeless" measurement of force, not the amount of work being done. RPM's add the "time" factor (how many times per second is that force being applied). Horsepower is our goofy name for the measurement of work being done. More torque at low RPM's means more Horsepower at low RPM's. More Horsepower means more work being done resulting in acceleration.

HP=TQ*RPM/5252. Acceleration is always about the amount of work being accomplished by your engine vs. the drivetrain losses, air resistance, weight, inertia, etc...

(vastly simplified)

Very good simplified explanation!
If I may add just a little to reinforce the point, and again vastly simplifying, you have to look at the area under the torque curve on the graph. An engine may have a higher peak torque and higher peak power, but could be out dragged by an engine with lower peaks but a much larger area 'under the curve' (at least until the point where more peak power is required to overcome aero and other drag).
Also, don't forget that a torque converter will multiple torque until it locks, effectively boosting a torque curve at low(er) rpm's.
A couple of other observations:
1. The ~530hp peak does not surprise me and is consistent with reviews that I have seen that say the car feels like it has a lot more than 500hp.
2. There is something wrong with the data in the screen shot NightWriter posted on the torque conversion - there is a 9.8% difference in the Nm numbers, but only a 6.4% difference in the lb-ft numbers.

[NightWriter]

Originally Posted by TJR_M3

Very good simplified explanation!
If I may add just a little to reinforce the point, and again vastly simplifying, you have to look at the area under the torque curve on the graph. An engine may have a higher peak torque and higher peak power, but could be out dragged by an engine with lower peaks but a much larger area 'under the curve' (at least until the point where more peak power is required to overcome aero and other drag).
Also, don't forget that a torque converter will multiple torque until it locks, effectively boosting a torque curve at low(er) rpm's.
A couple of other observations:
1. The ~530hp peak does not surprise me and is consistent with reviews that I have seen that say the car feels like it has a lot more than 500hp.
2. There is something wrong with the data in the screen shot NightWriter posted on the torque conversion - there is a 9.8% difference in the Nm numbers, but only a 6.4% difference in the lb-ft numbers.

Good catch, although it's actually an 8.9% difference in the NM (60/670). I'm guessing they typo'd the wrong lb-ft for the Comp (should be 494, not 479), but just speculating.

Either way, another important part of the equation is the actual traction laid to the ground; With more torque at lower speeds and aided by AWD, those three components together will make a G8xC XDrive feel much faster off the line (because it is). Another reminder that dyno's aren't everything.

[TJR_///M3]

Originally Posted by NightWriter

Good catch, although it's actually an 8.9% difference in the NM (60/670). I'm guessing they typo'd the wrong lb-ft for the Comp (should be 494, not 479), but just speculating.

Either way, another important part of the equation is the actual traction laid to the ground; With more torque at lower speeds and aided by AWD, those three components together will make a G8xC XDrive feel much faster off the line (because it is). Another reminder that dyno's aren't everything.

We are both correct - I did the math the other way 60/610

As these guys are European I will assume that the 670 Nm is correct so it should indeed be 494 lb-ft - 479 lb-ft is the advertised number

[ROBERT1183]

Coming from a F80 6 speed comp to a G80 6 speed It definitely feels like more than the 29hp difference on paper. Car pulls alot harder. Feels like BMW sandbagged on the numbers.

[razman]

Originally Posted by TJR_M3

We are both correct - I did the math the other way 60/610

As these guys are European I will assume that the 670 Nm is correct so it should indeed be 494 lb-ft - 479 lb-ft is the advertised number

Good catch.