z98

Exactly.

Just use 15% for a manual, 18% for an auto.

Close enough for anyone.

KrazyDan

nice sig z98. LOL

Joker

From what I understand, and someone please correct me if I'm wrong, you take the rear wheel hp and devide it by .88 (.82 for an auto trans) to get the flywheel hp.

The deviation in this is that all cars are different in parasitic loss and other variables including temp will make a difference, so the formula will be skewed for each individual car. Just what I've heard from different mechanics and tuners. Hope this helps a little.

Example: my car did 389 at the wheels, 389/.88=442, so at the flywheel mine is doing approx 442 hp, with the same formula being used to calculate the tq.

Ant's-WS6

Dude your sig is hilarious!

LSWannabe

Oh man, you guys are all a bunch of boneheads. Joker we are using 15% for a manual since it is just an estimate. As previously stated no two cars are the same. Anyway all you primates need to listen to Jane Goodall next time she joins you "in the mist". Take RWHP multiplied by 1.15 to get FWHP. 308*1.15 = 354.2 fwhp There now I cleared everything up.

You guys know I'm just QUOTE=Unit213 "bustin *****" QUOTE. And I am glad to see that the probs in the beginning of the thread were smoothed out. Also if your talking to anyone who doesnt know **** about cars, your best bet is to tell them fwhp since thats what car manufacturers use in their ads. So you tell me, what sounds better when your trying to talk a hot chick into taking a ride with you. "Yeah, my car makes 320 rear wheel horsepower." To her all she hears is "Blah, my car makes 320 blah blah horsepower." Or you can say "My car makes 375 horsepower.""You wanna go for a ride?"

Since it's an estimate you can "spot yourself a couple ponies". Just make sure you live up to ALL her expectations.

Joker

[QUOTE=Joker]- Just what I've heard from different mechanics and tuners.[/QUOTE

Mike K.

I have actually tested this and it is actually at 15% drivetrain loss for a manual. Don't by the same hp loss no matter what hp you have, its 15% (roughly) no matter your power lvl,, so the more power you have the more you lose, reason for this is because when you have more power you spin the drivetrain faster which also takes more power. Good test, jack up the rear of the car, put in nuetral , spin driveshaft at a certain speed, then spin it faster and see how much harder it is.

BlueSix

your 308 * 1.15 is wrong buddy. That equals 354.2, but when you take 85% os 354 you get 301....hmmm, something don't add up. 308/.85= 362

It's only a few hp, but i thought you should know how to do the math.

99FormulaM6

iTrader: (21)

and people say its useless, but its actually used alot. like said above, every car company uses it in their ads, and i know for certain when people get custom stripes and decals, they dont use rwhp...its fhp. but i know when i tell my friends or their friends i use rwhp, but i do specify that its rwhp, only cause i know they know what im talking about.

LSWannabe

Unit and I both got 354.2 for our answer. The original math is not<-EDIT correct. 15% of 100 is 15, 100*1.15=115. Your formula is flawed 100/.85=117.6 Hmm.

Your just getting on my case because of that downshifting thread.

EDIT- Bluesix, I thought about it more and changed my mind. You are correct.

Unit, I believe you and I have our wheels turning backwards. While our good friend BlueSix has them turning in the right direction. We are taking 15% of a number that has already had 15% taken away from it. The number to the ground already suffered driveline loss so 15% of 308 is 46 (decimals removed). Whereas taking 15% of the number from the crank 362=54, 362-54=308.

BlueSix

Thank you, i'll be here all week.

zamboxl

iTrader: (1)

all i got to say is thank got for this site and for threads like this, sure make work alot mor entertaning.

ActionJack

Unfreakin beleivable. This thread is border line hilarious/stupid.

A thread that should have been 6 posts tops (now over 50 and I am adding my own ignorance to it)...

1st Post

"I have heard everything from 15-18% for a M6 car. And I have heard it's closer to "50hp". Can somebody who REALLY knows chime in here please? My last dyno I put down 308hp and it was 98 degrees and very humid in that shop last July. So where am I? My car is stock with just LM and Y pipe and a lid. There has to be some formula that we can use consistently. After I do my cam/headers/intake install I will do another dyno but I want to have a fairly accurate idea of what I have at the crank. Thanks in advance"


Answer:

Guesstimates based on a 15% (M6) to 18% (A4) over RWHP for a FWHP.

If you need more than a guesstimate than take the engine out and put it on the machine.


* Also, I have read elsewhere that the guesstimate is more like 10% to 15% (m6) or 15% to 20% (A4). IMO there is no known way to do the FWHP without getting it directly from the engine.


Also another thread on it at www.ls1tech.com:

Link #1

'02 SLP#686

iTrader: (1)

The UNIT guy needs to understand that Ford had to put a FORGED/SUPERCHARGED motor in a Mustang to get it to hang with the LS1. Go spend some time at the track and watch how many times you need to wait while they mop up the track after one pops the rear on the line...

Before you get all pissy UNIT, I have two buddies with '03 Cobras, one with the 2.2 Kenny Bell and he makes some sick power... I'm just reminding you that we are on an LS1 board and I am just breaking some friendly *****

99FormulaM6

iTrader: (21)

Unit is very respected here, and is very knowledgable on a wide variety of subjects. he might own a ford now but he hasnt always.

'02 SLP#686

iTrader: (1)

I meant no disrespect - Unit has answered a few of my posts with accuracy and correctness. I posted for no other reason than the FORD/GM rivalry

macdad

loser

'02 SLP#686

iTrader: (1)

Proud of your first post?

Ru2n00n3er

iTrader: (13)

Thank you, I was reading through this post and was getting worried about the educational system in America. Someone was smart enough to get it right, and then others were smart enough to realize it after. I feel better now. I really don't care at all about drivetrain loss, but it's nice to have a number when you're stock and haven't dynod it yet. Then you can say my car supposedly has (insert factory rating) but is really only pushing so much at the wheels. At that point I think it's nice to know, just so you can have an idea of what it might be.

LSWannabe

I was going to say something until I saw you were just messing around.

We all know Unit only owns a cobra because of the factory blower/forged motor. 03-04 Cobras arent hanging with LS1's, they are shutting them down. Stock vs Stock, Modded vs Modded, drivers being equal blown cobras > LS1 f-bods. I am making a general reference here. Because generally it is true. Of course there are a million ways to mod. Save the flames, I know the LS1 can be made to win.

macdad, that was an intelligent response.