Cjunkie

according to Wikipedia GM underrated the engine by 20hp giving it a true hp rating of 425 (02-04 versions)......hmmmmm i wonder if this was done for the the then new C6 rolling out?

Nulltime

405 is a correct average. That being said there have been a few factory freaks with about 10 to 15 more hp.

500hp

Back when GM High Tech Performance magazine tested the new 2004 Z06, they estimated their test car at 424 FWHP, using their observed RWHP# and doing the math. They got the car into the 11.9s after only a few 1/4 mile runs, bone stock--tires and all, so they had no reason not to believe such figures.

As for the new LS7 cars, we only have to see what the tuners are getting out of them by only re-tuning on the dyno. If you look at the LS7 head flow numbers, the only thing holding back the 427 is the relatively 'mild' cam timing/phasing, and GM's attempt at a "politically correct" tune aimed at the obvious emissions and fuel economy constraints.

mqqn

Hi Cjunkie -

Wikipedia can be updated by anyone. I do not believe that any of the "facts" on Wiki are verified.

An excerpt from the Wiki "about us" page.....

Most 02-04 Z06's were, in experience, putting out pretty near 405 hp factory, and putting 350-360 hp to the rear wheels.

The article that the Wiki "quotes" shows that the people who tested the GM provided "press" car achieved 363rwhp on a dyno - using 15% drivetrain loss, that comes to 417 fwhp - not 425 as they somehow calculated (and they used 13% drivetrain loss factor - so I don't know where they came up with 425....).

Moral of the story - don't believe everything you read on the internet - or Wiki.....

best rergards -

mqqn

03 Z-oh-6

My bone stock 04 Z06 dyno'ed 359.90 HP SAE, so with 15% drivetrain loss, that would put it at 423 Fly wheel HP.

mtm87tx

it all depends on what correction factor you use

15% at 350-360rwhp stock is 411-423 at the crank

12% at 350-360rwhp stock is 397-409 at the crank

mqqn

Hi Ditch -

How are you calculating that number?

360 * 1.15 =414.0

best regards -

mqqn

mtm87tx

you divide by .85 to go from rwhp to crank hp

Bigstik

This way of calulating the drive train loss is only adding 15% to 360, its not subtracting 15% from 423.5.

the calculation should be:

360/0.85 = 423.529-----this is the same as (423.529 * 0.85 = ? RWHP)

mqqn

Hi Guys -

Thanks - that makes sense then, and my car is making (according to this) 458.8 fwhp.

And I still cannot get it in the 11's.

best regards -

mqqn

03 Z-oh-6

360/.85

Cjunkie

when my car had 1800 miles i made 3 pulls 363,363 then we let it set for about 35 mins with the fans on it and a bag of ice on the intake and got a 366.

MikeP

My Z16 making 420 RWHP + 494.11764 FWHP. Sure drops going through the drive train.

Mike

Vetteoholic

My 02' did 356 when It was stock. I think they generate a little more than the factory rated 405 figure. Every same kind of car is different though obviously.

Wicked_Z06

So this means I have 505hp, and 588tq at the crank...@ only 4500rpm. Not to shabby...

sweeet

Millenium Z06

359.9 X 115% = 413 Flywheel HP unless I managed to do the math wrong.
I think the 405 number represents an average from GM; I remember reading that they tested a string of LS6's and the lowest powered average they got became the rating. I also believe that they are all pretty close to 405 410 hp.

mqqn

Hi Guys -

After thinking about this for a while today, I had the following thought.

Drivetrain loss for a given car should be static - the cost of driving a specific drivetrain would not have a linear correlation to the output of the engine driving it.

In other words - if it takes x hp to turn the drivetrain, why would it take x+ to turn the same drivetrain if the force driving it was increased?

To look at this yet another way, say my car makes 390 rwhp, and doing the rwhp / (100 - drivetrain loss percent) it raises the number to 458. That seems to indicate that it takes roughly 68 hp to turn the drivetrain and accessories.

So why, if I increased (or decreased) the output of the engine, would the drivetrain take more or less power to drive it? If my car were making 490 rwhp, using the "generally accepted" equation, my exact same drivetrain now takes ~86 hp to turn it. I just picked up 18 free brag-powers.

Seems to be a flaw in the logic here - or is it just me....again

I assert that the higher the rwhp number plugged into the equation, the more invalid upward skew is built in.

best regards -

mqqn

CJR2

2TONE82

Here's the run sheet on my Z16 - bone stock with about 11K miles on the clock. Previous owner dynoed the car about 3 months before I bought it...as he picked up a C6 Z.

The numbers from the run file: RunFile_005.drf - 11/18/05 6:46:28 PM Run Type RO Run Conditions 60.65 degrees f, 29.66 in-Hg, Humidity 9%, SAE 0.97

This was a SAE corrected pull. The Raw numbers can be obtained by dividing the HP & TQ numbers by the SAE factor (0.97) i.e., 355.42/.97=366.41 HP. Either way that's about a 10 to 12 percent loss through the drive train.

ctusser

There may be some truth to that as far as frictional losses, but a lot of the HP loss is in accelerating the mass of the drivetrain. The more HP the faster you accelerate the parts, but the faster they accelerate the more the inertia of the parts resists the acceleration, so it is pretty constant.