[BMW GENIUS]

Thank you everybody for your input and help! I will definitely go back and see if anything is different with a 4th gear pull if I can! I apologize if I came off as rude or a jerk. Has anyone ever dyno'd on a dynocomp? I wonder what makes these big differences between dyno models?

[pikcachu]

Originally Posted by G-Mann

Manual?

AT8....

Also all 3 runs where consistent 280whp 240 lbs/ft so it's not like just a fluke run

[rpagianotto]

Originally Posted by pikcachu

AT8....

Also all 3 runs where consistent 280whp 240 lbs/ft so it's not like just a fluke run

I got 325 whp and 45wkgf/m which is about 330 ft/lb, on 5th gear, on several runs. However, one thing that might explain this is that the gasoline here has 25% ethanol in it.

http://www.2addicts.com/forums/showt...php?p=17422357

What kind of gas were you running?

[Buckeyes]

Originally Posted by pikcachu

AT8....

Also all 3 runs where consistent 280whp 240 lbs/ft so it's not like just a fluke run

240 lbs foot is pretty low. The n55 makes more torque then hp.

[pikcachu]

Originally Posted by rpagianotto

I got 325 whp and 45wkgf/m which is about 330 ft/lb, on 5th gear, on several runs. However, one thing that might explain this is that the gasoline here has 25% ethanol in it.

http://www.2addicts.com/forums/showt...php?p=17422357

What kind of gas were you running?

92 i think here is 10% ethanol

[Daleb]

The link below has the specs for the 8AT in our cars. At the very bottom are the ratios for the gear box.

It is 6th gear for a 1:1 ratio but I believe we may be speed limited in 6th so 5th is the best option.

1st 4.70
2nd 3.13
3rd 2.10
4th 1.67
5th 1.29
6th 1.00
7th 0.84
8th 0.67

http://www.europeantransmissions.com...ansmission.htm

[allthatisntnow]

Yeah, wheel torque should be at around the factory claimed crank level. So around 370 actual crank torque. I think a lot of the runs are influenced by the humidity and temperature too. Cooler, denser air would be more on the ideal side for dyno pulls id have thought.

Does the 8AT suffer from greater losses than the 6 speed manual?

[BMW GENIUS]

Originally Posted by allthatisntnow

Yeah, wheel torque should be at around the factory claimed crank level. So around 370 actual crank torque. I think a lot of the runs are influenced by the humidity and temperature too. Cooler, denser air would be more on the ideal side for dyno pulls id have thought.

Does the 8AT suffer from greater losses than the 6 speed manual?

I think temperature and humidity would have a negative effect. Hotter air = less dense air, more humidity = more water in the air than oxygen.

Also, its been known that auto transmissions tend to have about 20% powertrain loss compared to the average manual's 15%

Also, I forgot to mention I had ethanol free 93 octane! Stupid me.

[allthatisntnow]

Originally Posted by BMW GENIUS

I think temperature and humidity would have a negative effect. Hotter air = less dense air, more humidity = more water in the air than oxygen.

Also, its been known that auto transmissions tend to have about 20% powertrain loss compared to the average manual's 15%

Also, I forgot to mention I had ethanol free 93 octane! Stupid me.

It would be interesting to see what the revised ZF 8 speeds were like. I know they do a fair bit to refine the efficiency of the whole system (reduce frictional losses, lower weight, optimise the software etc) and the ones in the 2 series aren't the latest revision. For sure humidity and high temp will have a negative effect on power generation. Well, humidity in the right form can be an aid, e.g. water injection being used to cool charge temps etc.

[BMW GENIUS]

Originally Posted by allthatisntnow

It would be interesting to see what the revised ZF 8 speeds were like. I know they do a fair bit to refine the efficiency of the whole system (reduce frictional losses, lower weight, optimise the software etc) and the ones in the 2 series aren't the latest revision. For sure humidity and high temp will have a negative effect on power generation. Well, humidity in the right form can be an aid, e.g. water injection being used to cool charge temps etc.

Point well made! I'm so glad we have a great community with all this knowledge in all corners to help address issues like these!

[pikcachu]

Originally Posted by BMW GENIUS

I think temperature and humidity would have a negative effect. Hotter air = less dense air, more humidity = more water in the air than oxygen.

Also, its been known that auto transmissions tend to have about 20% powertrain loss compared to the average manual's 15%

Also, I forgot to mention I had ethanol free 93 octane! Stupid me.

but if the transmission was the difference then HP should be down too.... and HP seems kind of inline with 320hp crank - 18% drivetrain loss but in my case torque makes no sense at all