RWHP vs. flywheel

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Dec 1, 2004 | 11:13 AM

#16

turbo_Z

Registered User

Joined: Nov 2001

Posts: 3,515

From: Kansas

Re: RWHP vs. flywheel

I was told it was 16% at the dyno. Seemed a bit high but I didnt question the man because really I could care less what the FWHP is.

Dec 1, 2004 | 12:12 PM

#17

Injuneer

Administrator

Joined: Nov 1998

Posts: 71,121

From: Hell was full so they sent me to NJ

Re: RWHP vs. flywheel

Quote:

Originally Posted by 1racerdude

Man--- that sounds like a big gain(or loss) for a stick--figuring it at 16%.Thats more like an auto with a converter and a 9".16% must be way high. The 10-12% sounds more reasonable to me but I have not dynoed every car on the planet,just a few.

Dude... I am NOT..... repeat NOT.... NOT saying the losses are 16% for a "stick". I've already explained that I believe, based on actual measurements, that its in the range of 12-13%. I was only using the 16% to match the numbers "97bowtie" used so that he could understand why what he said was wrong.

Another thing to remember..... the drivetrain losses are based on inertia losses (do not vary with flywheel HP) and friction losses (vary proportional to flywheel HP). Hence, it is NOT a fixed percentage, but a variable one. I found it ranged from 12.6% at 500flywheel, to 12.2% at 800flywheel in the dyno test on the engine. The losses on a stock engine will be a larger percent than they will be on a 500HP engine.

Dec 1, 2004 | 01:02 PM

#18

stereomandan

Registered User

Joined: Jun 2003

Posts: 3,620

From: Saginaw, Michigan

Re: RWHP vs. flywheel

Quote:

Originally Posted by turbo_Z

I was told it was 16% at the dyno. Seemed a bit high but I didnt question the man because really I could care less what the FWHP is.

I totally agree with you there. It's the power that you put to the ground that matters.

Dan

Dec 1, 2004 | 01:05 PM

#19

97bowtie

Registered User

Joined: Nov 2000

Posts: 1,148

From: AZ

Re: RWHP vs. flywheel

Quote:

Originally Posted by Injuneer

No they aren't, and no you can't. If you accept that the losses are 16%, you can either divide rwHP by 0.84 [1.00 - 0.16 = 0.84], or you can multiply rwHP by 1.1905 [ = 1 / (1.00 - 0.16) = 1 / 0.84 = 1.1905].

414 / 0.84 = 493 flywheel

414 X 1.1905 = 493 flywheel

I dunno what I was thinking...I guess Calc 2 diluted my recollection of the basics.

That's terrible.