Originally Posted by MadMaxx
1) Engine is over rated from factory (unlikely, based on what is available)
2) Not using a load bearing dyno / not using the correct corrections
3) Operators trying to make a buck with big numbers.
Doesn't change the fact that they ARE NOT UNDER ANY CIRCUMSTANCE achieving <9% driveline loss. Sorry bud, just ain't happening.
Since we're talking mustangs... you may actually want to read some of these threads where graphs are posted. You'll find that other folks, often who have been doing this for quite some time, call the numbers posted into question.
^ Start reading.
Magnaflow had a hard time getting above 300rwhp with an exhaust change... on a 2010 (315bhp rating and a much better factory tune), etc.
Again, no one is arguing what a motor can or can't do, rather that the correction method you are implying (8% as "normal") simply isn't accurate. If a S197 mustang was rocking 280RWHP, she'd turn a far better time than a low 14 in the quarter. In reality, the S197 mustang puts down around the low 250hp mark (fordmuscle pulled the same number) which falls directly in line with it's power readings.
I've seen the 04-09 GT's consistantly in the 265-275 rwhp range. Ford does not SAE Certify most of their engines, therefore they can be both underrated or overrated. Same thing with most of dodge's Hemi engines (6.1). It's not that hard to fathom that the engines make more than their advertised power, especially since they are regularly in the 13's @ 102's-104's mph's (traps) in the 1/4. The '03 Cobra's are consistantly at 360-370 rwhp and they are rated at 390. I agree that 8% is too low, it's usually closer to 12%. Which would put the 300 hp 4.6's GT's really at 300-312 hp on average. (265/.88 to 275/.88).