Muscle Mustangs & Fast Fords
Paxton H.O. supercharger Kit Install - Paxton-Pumping Pavement Pounder
JPC Racing's '11 Mustang GT Jumps To 661 RWHP With A Paxton H.O. Supercharger Kit.
"In one section of the strategy where we used to have one spark table, we now have 16 tables," he stated. "We also have many more adjustments for cam timing than we did before. We can independently control intake and exhaust valve timing, bringing valve overlap into the picture, too. Not only is this used for making power, but it is also there for emissions and driveability. Making a calibration to perform seamlessly in all those areas requires a lot of time and effort." At press time, Paxton was working feverishly on a tune to include in its system, as well as earning 50-state emission-legal status.
Burcham did modify the kit to convert it from a draw-through MAF sensor to a blow-through setup. This was done because the Copperhead PCM uses a frequency-based MAF signal instead of the traditional voltage-based system on previous generations. This prevented the use a DiabloSport MAFia voltage regulator, which has been instrumental in the past with expanding the factory MAF sensor's airflow reading capabilities. A blow-through MAF sensor arrangement allows the meter to read greater than its 68-lb/min flow range.
Paxton advertises the boost rating of the kit as 7 psi, but that was rated at 6,300 rpm during the company's in-house testing. Burcham likes to twist his engines higher than normal and this one peaked at 6,700 rpm before the power started to fall off. The extra rpm came courtesy of the Kooks exhaust modifications and custom tuning.
The JPC test car saw 9.5 psi on the dyno and that resulted in a jaw-dropping 661 rwhp and 548 lb-ft of torque. Timing was set at 17 degrees on the chassis dyno and MacDonald backed it down to 14 degrees on track due to the greater load on the engine. While they saw 9.5 psi at the peak on the chassis dyno, the car registered 12 psi right before the finish line on track. The car was run on VP MS109 fuel for all dyno and dragstrip runs to provide a safety margin due to the high compression and boost.
"I think we are going to see many cars running around with 525-550 hp at the wheels before long," said Burcham. "If heat and detonation can be avoided, I think these engines will live a long life. Reliability is something we will learn more about as we see more people pushing the limits on a daily basis."
It's hard to believe, but 661 rwhp from a 5.0L with bolt-ons and a supercharger is pretty serious smoke. That rivals most modified Terminator and Shelby cars on the road and this is just the beginning.
Tune in next month to see how the JPC car performed in dragrace trim at our MM&FF 5.0 Shootout, which is on sale December 28, and be sure to check out musclemustangfastfords.com for exciting video action.