I had my car on the dyno and the numbers where low. The dyno tech said you lose 20% from factory specs can anyone tell me if thats true or not. 235 hp and 274 t.the car is basic 4.6 2004 gt engine should have 265 hp and around 300 T.

 

the loss of power you are experiencing is from the drivetrain. EVERY mustang experiences this. 12 - 15% loss of power. When ford says 265hp they are measuring the power at the engine , not the wheels so they can be more flashy and cool looking

 

Thanks for your responce. I have read that there is a 15% difference for a standard and a 20% with an automatic. I have also read there is a difference between the type of dyno used. I was on a mobile unit when i got mine done.

 

your average stock GT will dyno 225-230ish. dyno used and other things come into play, but thats about right.


the 260/300 rating from the factory is at the flywheel like sxgt said.

 

Depressing isn't it. Its 20 % on a auto. I had full bolt on and dyno at 256.4rwhp/290rwtq. I remember the first dyno tune on my sc. 344(generic tune). finally had it retuned in the car/fuel trims,timing,exhaust temps. ect, and ended up w./ another 20 hp. 235 rwhp for a stock stang is very good. there's be some sort of bolt on.

 

I have an offroad x pipe on it. Im thinking of getting a programer before i buy any more bolt-ons. After that its either a 373 gear change or a good coldair system.