cell6ida

Is there a formula I can use to find the flywheel horse power, from the dyno numbers of whp, for an automatic corvette?

I have heard that the automatic C6s 2006 + are usually 10 h.p. less at the wheels, rather than a higher percentage less. (Hope that made sense.) Correct me if I'm wrong about this please.


Thanks!

Boomer111

Can not help you with a formula but it is usually contended that a manual C6 will gain about 55hp at the flywheel. I believe that the auto will gain even a bit more, at least 10 hp maybe even 20hp at the flywheel from rwhp numbers. Meaning your auto loses more rwhp.

seevi

This is a ballpark formula that will get you very close for an A6 conversion to flywheel HP;

RWHP / .825 = FWHP

For example 330 RWHP / .825 = 400 FWHP

Boomer111

So 12% for manuals and 18% for autos. Ballpark...

seevi

I'm not sure I would go the 12% on the manual. Most reliable sources still stick to the 15% unless you gone to an after market clutch. 17 - 18% on the automatic from 2007 and newer is a good number.

Boomer111

Ya I figured mine at it was right at 15% Sae #'s on a Dynochassis.

seevi

Just checked your profile - what is your RWHP?

3 Z06ZR1

Mine stock figured at 15 percent also. So many dyno's are putting out inflated numbers.
Some on here have a stock Ls-3 making 400 rwhp. Take that same car to a another Dyno and it would make 375. So it's tough to figure.

seevi

I've seen an LS3 dyno out at 409 RWHP with nothing more than a mild tune, and then wonder why they can't catch an LS2 that dynos at 375 RWHP. I don't believe the numbers are inflated as much as the dyno is not set up for the load. An unloaded dyno run will give you numbers that will certainly make you smile and make you believe you're getting what you paid for. Then off to the track for the real eye opener.

Boomer111

It was around 376 rwhp and 381 rwtq. on a Dynapack. After tune and catted headers I'm seeing 422 both rwhp/rwtq on a Dynojet.

Actually made a mistake above, I got 12.5% on stock engine.

FastGhost

Here is a formula I was told to get the FWHP.

Divide .82 (automatic) into the RWHP and it will give you the FWHP
Divide .88 (manual) into the RWHP to get the FWHP.

PUNISHERC6

my 09 LS3 put down 378.9 hp and 380 lbs bone stock, back with a mamba cold air intake and a mild tune and it was up to 408.7 hp and 412.8 lbs. with cold air, long tubes, high flow cats and stock NPP mufflers in the open position and another tune, 441.7 hp and 446.1 lbs, which actually puts it around the power a stock Z06 puts down at the wheels, not bad for a little hobby shop work huh?

seevi

How was the dyno set up? Was it loaded or unloaded?

PUNISHERC6

it was loaded.

seevi

Should go like hell!

RWSjr

My research way back when i 1st modded mine gave me
A4 = .8475(based on mine and others)
M6 - .88 (based on several)
My stock dyno run(with K&N) 351.8RWHP or 415 Flywheel @ LG motorsports
Not an exact science to be sure, but a ballpark figure is better than nothin i suppose.

Gary Wells

I have been studying dyno charts & dyno #'s over on the Caddy forum as I have a new '09 CTS-V. I have come to some basic thoughts regarding parasitic loss from crank to RWHP & RWTQ for both auto & manuals. Dynapacks seem to read pretty high, dynojets seem to be middle of the road, I don't have enough data on mustang dynos & Dynomites.
The '09 CTS-V autos seem to be pretty steady at about a whopping 19% loss for both RWHP & RWTQ while the manuals seem to be pretty steady at about a 13% loss on the RWTQ and only a 12% loss on the RWHP. These #'s are based upon a Dynajet dyno and using 556 FWHP and 553 FWTQ. Just thought that you guys might like this for comparisons sake. I have this info documented on a word page and can post it if you like, but I don't want to get thrown off of the forum for posting Caddy data not directly related to vette stuff. HTH