Quick HP ?

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Apr 12, 2007 | 12:45 AM

vetteman012002

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From: Middletown MD

Quick HP ?

If a car makes 494FWHP what does it make to the wheels? I can't remember what the % difference is, and this is through an auto.

Thanks

Apr 12, 2007 | 01:05 AM

brucemoose2

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Joined: Nov 2002

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From: CT

Quote:

Originally Posted by vetteman012002

If a car makes 494FWHP what does it make to the wheels? I can't remember what the % difference is, and this is through an auto.

Thanks

Depends on the dyno, trans, etc. Lots of variables. Assuming this is a C5 with an auto... Very conservatively, 70% of the crankshaft hp - so 345.8. On the "ego-boost" end of the spectrum, 85% of the crankshaft hp - so 419.9. Take your pick...

Apr 12, 2007 | 01:30 AM

SLPRC5

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From: American Canyon Lethal Injection

Formula conversion is as follows.
Auto= divide RWHP by .82 and it will give you the flywheel HP.
M6= divide RWHP by .88 and it will give you the flywheel HP

Apr 12, 2007 | 05:13 PM

1965imp

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From: Chicago Heights ILLINOIS

Quote:

Originally Posted by brucemoose2

This is a very smart man. I hope everyone reads this

Apr 12, 2007 | 05:46 PM

kilrb

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From: Lenexa Kansas

Quote:

Originally Posted by brucemoose2

I don't get it... A '99 C5 is rated at 345 at the crank, and usually hit around 300-305 whp on a dyno, which is a 12.5-13% drivetrain loss for a manual. I believe an auto is between 290 and 295, which would be 15.5-16%. So why would you say 85% is ego-boosting. It might be a tad high, but I haven't seen many stock LS1's hitting 241.5whp (using your numbers). Not tryign to pick a fight, just confused.

Apr 12, 2007 | 06:07 PM

itchynackers

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From: Janesville WI

Maybe he's using the 1965 impala losses, which might be 30%.

Apr 12, 2007 | 10:30 PM

brucemoose2

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From: CT

Not all dynos will give you the same numbers. A Mustang dyno is not the same as a Dynojet. And many times the same brand dyno will give you different results. The question didn't specify enough details to give an accurate answer. He didn't say he was asking about a C5 - some of you are making that assumption - not that it's a crazy assumption... Anyway, 30% is not unreasonable for some transmission/rearend combinations. Corvettes just happen to have a pretty efficient driveline.

Apr 12, 2007 | 11:15 PM

1965imp

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From: Chicago Heights ILLINOIS

The proof is how these cars perform at the track-NOT WHAT THE DYNO NUMBERS ARE.

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Apr 13, 2007 | 09:06 AM

kilrb

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From: Lenexa Kansas

Quote:

Originally Posted by 1965imp

The proof is how these cars perform at the track-NOT WHAT THE DYNO NUMBERS ARE.

So you are saying Chevy marketed my 99 FRC at 345 crank hp, when it really had 435 crank hp? I know GM definitely under-rated the F-bodies, as they crank out the same whp numbers as their Corvette bretheren. But to assume that my stock 305whp C5 is really making 435.7 crank hp seems absurd...

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