S'vette

The % between going from crack to rwhp comes out different the when going from rwhp to crack. If you had 460 crack then it would be more like 390 to the wheels. So going from the wheels to the crack will be a little less than the 460. Use 15% as an example and you will see the difference.

Edited for crack power instead of crank. lol.

STROKD

Your math is rusty. Going either direction will net the same number. You divide by .85 not multiply by 1.15... His 404 is 475bhp at the crank. If you multiply the 475 by .85 you get 404 rw. Magic!

S'vette

The numbers were about 15% drive train loss. Go up 15% from 401 and see what you get and go down 15% from your high and see what you get. Now I havent seen that calculation before, what does the .85 represent? Ive always just heard of the drive train loss percentage being used.

STROKD

I understand what you are doing, and I was giving you the correct and actual formula. .85 is 85% or 100%-15%... If you take a given bhp number, to get a 15 percent drivetrain loss you take 85% of that number... To get bhp numbers from rw figures given, you divide by the same 85%, you don't multiply by 115% because you have a lower number you are adding 15 percent to instead of finding the original bhp number... Its pretty basic Algebra. Does that make more sense? I'm not real good at teaching or explaining my logic, my wife doesn't understand half what I say, she just nods and agrees. Lol

S'vette

Yea I looked it up and they were using the same numbers pretty much. And that was what I was kinda trying to point out that if you use the % way it will differ going back and forth. I didnt know the actual formula I just knew you couldnt take the 15% number from one way and use going the other way. So I see the .85 is a good way of going both ways (no dirty thoughts). His rwhp numbers are pretty high for stock thats for sure, the dyno was kind to him. Thanks for the formula.

STROKD

S'vette, np with the formula, glad to help.

Yea, the 397-404rw numbers puts that car at about 30-40 bhp more than it was rated, which is awesome... Its like having free mods on the car new power wise!

My 05 makes about 25-30hp more than its rated, so although not as much of a ringer, still happy it's not a dog... Ha

zzjakect

added Vararam and LG Longtube headers to LS2. Had it tuned by LG Motosports north of Dallas. Gained about 28 hp. Happy with that. Now the suspension is getting a going over. Need it to handle those twisties in the Ozarks!

handyandy1496

That puts you at 457 crank!

I usually use 14% for my 08 A6. It matches up well with some of the Wallace racing formulas.
ls3's sure love open exhaust and cold dry air. At the track, 1/8 mile, I get 89 mph stock. In very warm air. 89mph comes very close to 375rw per Wallace. 378 + 14%=430.92 crank. I since did bolt on's in cool weather 67* and ran in the 120.'s 1/4 mile and a 94.9 at the 1/8th on a cold day at 48*.

C6in816

i dynoed 396 stock cam, stock headers, stock underdrive pulley