These are a first for me, but I did see a report of 570 rwhp. No chart was posted. Anyone else seen numbers? Based on the performance that's probably pretty close.

 

It's distinctly possible the Ford GT is seriously underrated at 550hp, especially considering the 130+mph trap speeds.

 

Seems a little high. Should run closer to 10's with those dyno numbers.

Sam

 

yeh, with a trap of 130mph, you should be into the high tens. isnt the GT *only* in the mid 11s?
-Chris

 

What's this about "under-rating" does that make any sense? Would'nt they not rather say it's got 600hp or 610hp or so?

 

Here is an article showing that the Ford GT put down 565rwhp on the dyno

http://www.mustangweekly.com/2004/ma.../n03-6-3rd.asp

565 * .15 = 84.75

565 + 84.75 = 649.75 horsepower at the flywheel

 

uh not quite 69stranger.

565/0.85=664.7 horsepower at the flywheel. that's the correct way to figure it out.

 

Amen! So many people get that conversion wrong.

 

That's what I always thought. For supercars or very expensive cars, wouldn't they have a better image being more powerful than under-rated? It's not like 50 or 100 hp makes a difference with insurance or anything; regardless, insurance would still be super expensive already. In the 60's and 70's, that was the case, but not now with supercars. Btw, I think 565 rwhp is way too high. Maybe it's a special circumstance for that particular car?

Yeah, so many people calculate wrongly, like 69stanger. Here's a good way to look at it, 565 is only 85% of the original, so to find the original, one needs to divide 565 by the percentage point, which is .85.

 

I don't believe car makers "under-rate" their cars as often as people state.

Also, dyno numbers vary so much that I take the numbers with a grain of salt.

Dynos are good for tracking relative changes when you make adjustments to the vehicle, but to say the car has XXX rwhp x 1.15 = fwhp is just not valid.

As I understand, the drivetrain losses determined as a percentage of fly wheel horse power really are not valid on high HP vehicles. (HP>=300 HP) A more accurate "rule of thumb" is about 35 HP of losses due to the drivetrain (for manuals, slightly higher for automatics).

On my previous car, a 2003 Cobra Mustang, the baseline dynojet run was 359 rwhp and 349 rwtq on a completely stock car. Adding 35 HP to that number yields a flywheel number close to factory specifications.

Notice the torque was a little low but the horse power was a lilttle high. Based on those numbers, that 35 HP adjustment seems reasonable.