My Ford GT on the dyno...

[FikseGTS]

My GT arrived at Heffner's and put down 525 rwhp SAE stock.... pulley and tune #'s coming soon, I'm picking up the car tomorrow!

 

[FikseGTS]

623 rwhp after the pulley and tune..... waiting for the graphs....

 

[tmcphail]

Nice !!

 

[Mullet]

Using 91 or 93 octane?

 

[Superfly]

Dig it!

 

[FENZO]

Sweet. Which pulley tune?

 

[FikseGTS]

good question about the gas, car came from California, San Francisco area, might have had 91 in the tank.... Heffner pulley and tune....

 

[gtforme]

What is the cost to have the pulley and tune done

 

[FBA]

I don't get it - these things are supposedly 550 HP at the crank...how does that translate to 523 RWHP? Are the engines that underrated? If we're looking at a 15% drivetrain loss, that would translate to 618 Crank HP. Is that what these really are? I see high in the 470's on stock GT's on dragtimes.com...

 

[FBA]

What is the cost to have the pulley and tune done

Depends on whose pulley and tune...Ford racing has that kit for 999.95 + install, so around $1300...but there are other higher performance tunes with pulleys costing double that.

 

[RALPHIE]

I don't get it - these things are supposedly 550 HP at the crank...how does that translate to 523 RWHP? Are the engines that underrated? If we're looking at a 15% drivetrain loss, that would translate to 618 Crank HP. Is that what these really are? I see high in the 470's on stock GT's on dragtimes.com...

Yes - they were highly underrated for EPA and CARB (& Ferrari?), I believe - and to keep the Gas Guzzler Tax to a minimum.

 

[FikseGTS]

Heffner said he has seen anywhere from around 480 to 530HP at the wheels for stock cars..... pretty big range.... they are underrated for sure.... 15% driveline loss with 623 HP at the wheels is 732HP...

I don't get it - these things are supposedly 550 HP at the crank...how does that translate to 523 RWHP? Are the engines that underrated? If we're looking at a 15% drivetrain loss, that would translate to 618 Crank HP. Is that what these really are? I see high in the 470's on stock GT's on dragtimes.com...

 

[Fast Freddy]

the rear engine and transaxle have only 10% drivetrain loss + 4th gear is not a 1:1 ratio it is a .94:1 ratio....

 

[Art138]

FikseGTS

Did you get the Accufab throttle body also???I got the pulley, tune,said throttle body, and high flow K&N air filters from Heffner....I wonder if there is any difference in the Tune between the one he installs at his shop vice the SCT programer one he sends with the kit.???

 

[KJRGT]

I don't get it - these things are supposedly 550 HP at the crank...how does that translate to 523 RWHP? Are the engines that underrated? If we're looking at a 15% drivetrain loss, that would translate to 618 Crank HP. Is that what these really are? I see high in the 470's on stock GT's on dragtimes.com...

Doesn't bother me at all!
My stocker laid down 585 RWHP when Torrie was in town giving a number of us his custom tune.

 

[FBA]

AFAIK, gearing shouldn't affect RWHP as the Dyno doesn't care or know about gears, but ya, I get the 10% drivetrain loss, seeing as it's such a short run from the engine --

 

[tmcphail]

Doesn't bother me at all!
My stocker laid down 585 RWHP when Torrie was in town giving a number of us his custom tune.

:cheers:cheers

 

[dbk]

That's a good number for Heffner's dyno. You're not getting any puffed numbers from that thing.

Jamal always told me that a Ford GT motor on an engine dyno would generally put down about 575 hp.

 

[Indy GT]

I don't get it - these things are supposedly 550 HP at the crank...how does that translate to 523 RWHP? Are the engines that underrated? If we're looking at a 15% drivetrain loss, that would translate to 618 Crank HP. Is that what these really are? I see high in the 470's on stock GT's on dragtimes.com...

Yes (again).
And I think your assumption of 15% drivetrain loss is much too high....

 

[GT35065]

FikseGTS, which exhaust are you running. I have Heffner pulley, tune, and exhaust done at his shop and have been very happy with it. If you have stock exhaust, look in to changing it.