Dyno Battle: 2018 M3 Competition vs 2018 M4

[Nikolas]

Originally Posted by paliknight

I'll try searching for them later but I've seen dynos for stock F80s around or a bit higher than crank. I don't think it was on a mustang dyno but I've seen and read it on here before. I never dynoed my car myself so I don't know what to believe personally.

The only one it could be would be a dynapak as the wheels are removed and the hubs mounted to the dyno, significantly reducing drivetrain loss.

[420Coupe]

All Dyno #'s are to be used as a tuning tool; ie establish a base and use to overlay with after tune to establish real gains. All dynos have their formula for estimating HP, ie inertia vs load dynos.

Plenty of ways to modify the formulas for them to show #s you want; Dyno Queens always make me laugh in the comparison of charts.

IMHO most accurate measure of power is using ET, Trap speed and weight.

[Nikolas]

Originally Posted by 420Coupe

All Dyno #'s are to be used as a tuning tool; ie establish a base and use to overlay with after tune to establish real gains. All dynos have their formula for estimating HP, ie inertia vs load dynos.

Plenty of ways to modify the formulas for them to show #s you want; Dyno Queens always make me laugh in the comparison of charts.

IMHO most accurate measure of power is using ET, Trap speed and weight.

Exactly!

[Hedoniste]

Originally Posted by SeanWRT

It makes front page because no one seems to have done back to back dyno with base and comp.

And all these days we're made by 'not same day dyno overlay' to believe ZCP has more torque at low to middle range, are over. Simply not true. Difference is at top end only.

This thread is much more front page worthy than most of rumor/speculations or official news shits.

ZCP have less torque at low range... here is the BMW technical data:

[Venere]

Originally Posted by Hedoniste

ZCP have less torque at low range... here is the BMW technical data:

Wow, that shut everybody up. Nice mic drop Hedoniste. So, basically, the ZCP is a detuned Civic engine with LESS torque at lower RPMs for the folks who haven't learned how to modulate their throttle for best traction? This may explain why some mags have recorded LOWER accel times for standard cars. Better drivers perhaps?

[Circuit Hunter]

Interesting results, thanks for doing this. Makes sense why the comp pack puts down power better.

[CanAutM3]

Originally Posted by Nikolas

The only one it could be would be a dynapak as the wheels are removed and the hubs mounted to the dyno, significantly reducing drivetrain loss.

Technically speaking, tire rolling losses are not drivetrain losses.

[CanAutM3]

Originally Posted by Hedoniste

ZCP have less torque at low range... here is the BMW technical data:

Thank you for sharing this. It is the first time I see official BMW documentstion to that effect.

It is important to note that we are only talking about a 500RPM difference before max torque kicks in in the very low portion of the rev range (1850RPM vs 2350RPM).

[CanAutM3]

Originally Posted by Venere

Wow, that shut everybody up. Nice mic drop Hedoniste. So, basically, the ZCP is a detuned Civic engine with LESS torque at lower RPMs for the folks who haven't learned how to modulate their throttle for best traction? This may explain why some mags have recorded LOWER accel times for standard cars. Better drivers perhaps?

That torque reduction more than likely has zero effect on a max acceleration launch. When doing an optimal launch and acceleration run, the engine RPM will always be above 2350RPM.

See this thread, on average, the CP does out accelerate the non-CP: http://f80.bimmerpost.com/forums/sho....php?t=1376759

However, the slight very low RPM detune surely helps tractability in regular driving.

[CanAutM3]

As a tidbit, I always chuckle when folks refer to the "torque at the wheels" numbers obtained on a chassis dyno. That number is purely fictive and does not exist in real life. It is simply calculated from the wheel power divided by the engine RPM. It is an interresting number to look at for comparisons, but it is not the "torque at the wheels".

The real world "torque at the wheels" is always augmented by the transmission and final drive gear ratios while torque at the flywheel is free of drivetrain loss. You cannot intermix both.

[SeanWRT]

Originally Posted by Hedoniste

ZCP have less torque at low range... here is the BMW technical data:

Yes. That aligns well with the reality.

Only too many dyno overlays wanted to prove ZCP build up power quicker from low end. Which is not true.