Drive Line loss on AWD - 6SpeedOnline - Porsche Forum and Luxury Car Resource

May 25, 2007 | 01:30 PM

jags911tt

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Drive Line loss on AWD

Hey guys what is the drive line loss when doing a AWD dyno? I think its like 18% correct?

Jag

May 25, 2007 | 01:35 PM

ef996TT

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might be 20...i think

May 25, 2007 | 01:58 PM

Origyns 973

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Quote:

Originally Posted by jags911tt

Hey guys what is the drive line loss when doing a AWD dyno? I think its like 18% correct?

Jag

I've researched this quite a bit, with the stock weight fly wheel, it seems that the general concensus seems to be between 18% and 20% for drive train loss on the awd cars. And approximately 12% to 14% on the rwd cars.

All of this changes when you get a lighter flywheel, more abrasive clutch, etc.

May 25, 2007 | 02:12 PM

willcoxmd

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willcoxmd is infamous around these parts

Jags,

On Alex's dyno. if we use 20% loss, does that mean my 515 HP to wheels is approx 618 HP at the flywheel?

May 25, 2007 | 02:16 PM

Origyns 973

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Oh and to further elaborate my percentages are on the dynojet style dyno, other dyno's have different correction factors.

May 25, 2007 | 05:04 PM

jrok

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My '01 TT recently did a 467 HP / 475 TQ on an in-ground Mustang 1100 Series dyno for NASA Time Trail qualifications. I do have a LWFW and Sach's sport/race clutch and was wondering what the loss ratio is for this setup. If anybody has any idea what the crank horesepower might be I'd love to hear.

May 25, 2007 | 05:09 PM

jags911tt

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Quote:

Originally Posted by willcoxmd

Jags,

On Alex's dyno. if we use 20% loss, does that mean my 515 HP to wheels is approx 618 HP at the flywheel?

Yes is you did a run with the drive shaft connected.

Jag

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May 25, 2007 | 10:43 PM

Craig

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I too have heard 18 to 20% for manual transmissions, with an additional 5% drivetrian loss for Tiptronic transmissions.

My car recently produced 755 AWTQ (@ 3900 rpms, in 103 degree ambient temperature). Using a 23% drivetrain loss, that equates to 980 FWTQ.

Craig

Last edited by Craig; May 25, 2007 at 11:35 PM.

May 25, 2007 | 11:00 PM

jags911tt

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Quote:

Originally Posted by Craig

I too have heard 18 to 20% for manual transmissions, with an additional 5% drivetrian loss for Tiptronic transmissions.

My car recently produced 755 AWTQ (@ 3650 rpms, in 103 degree ambient temperature). Using a 23% drivetrain loss, that equates to 980 FWTQ.

Craig

WTF - and I thought you said Joe was making more power than you. Great numbers Craig.

Jag

May 25, 2007 | 11:11 PM

#10

Craig

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Quote:

Originally Posted by jags911tt

WTF - and I thought you said Joe was making more power than you. Great numbers Craig.

Jag

Thanks Jag. Joe will be maing more power than me at the wheels after he gets his new tune with the Hitachi MAF. With my larger valves, I may make slightly more power at the crank, but not enough to overcome my additional powertrain loss, so Joe will exceed my power at the wheels very shortly.

Craig