First dyno pull

Nice numbers. Ford actually did you a little better than advertised ;).

The factory rating is taken at the transmission tailshaft, so the only loss would be from the rear end and that certainly shouldn't be 15%, it shouldn't be more than 15HP. The factory numbers are "typical" ones adjusted to optimum temp and humidity (70 degrees F and about 40% humidity). You didn't say if those figures were "adjusted" for your temp, humidity and altitude above sea level, which would add some power, and I would suspect that you may have also had some loss from wheelspin. I'd guess that you're probably actually getting very close to the factory rating, if all factors were taken into account.

Factory ratings are at the crank, not the tailshaft of the trans, and 15-18% is a good number for an estimate of drivetrain loss.

why such a weak blower for the new 03 Cobra? It seems like with any other blower should throw its HP rwell over 400?

Exactly. Otherwise there would be different hp ratings for manual and automatic cars.

Cat-back, CAI, and x-pipe are all it takes to hit 400 rwhp at the stock boost (8-10 psi) :). The only downside to this blower is that it reaches it's efficiency limits at around 16 to 18 psi, which is right around 500 rwhp (with some other bolt-ons helping ;) ).

Sorry, but by federal law, all HP and torque readings on cars MUST be taken at the tailshaft of the transmission with "all accessories attached and operating"! It's not uncommon for a company to fudge a bit and choose a non A/C, non P/S model to get the readings from and then use it for the whole line, which is allowable under federal law. The car makers haven't been allowed to use flywheel HP ratings since 1973, which accounts for much of the huge drop in ratings between near-identical '73 and '74 models. Companies are allowed to use flywheel readings only on crate engines, which is reasonable, since they have no idea what kind of car it will be going into.

I'd be interested to see the documents that require the inclusion of the transmission under federal mandate. My understanding is that the automotive manufacturers are required to use the standards SAE J1349 JUN1990 for net power and J1995 JUN1990 for gross power.

Under SAE 1349 the tester is required to measure the motor "fully equipped". The standard defines "fully equipped" to mean that the motor has all accessories required to perform it's intended service, it is not necessary to include components required to power auxillary systems. There is no

Since the SAE standard doesn't require it there must be some federal regulation somewhere that does. Could you point me to it?

Which federal law mandates this? I thought it was just an agreement between manufacturers to use an SAE approved method. I also thought they still measured it at the engine crankshaft, not the transmission output shaft.

Regards,

Ed White