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.
It should be no secret that the '11 Mustang GT comes equipped with a 412hp rating (roughly 365 rwhp behind a stick-shift on most chassis dynos) thanks to 302 ci, four cams, four-valves-per-cylinder, and a hefty 11:1 compression ratio. Ford certainly gave us a stout starting point in the latest edition of the late-model EFI wars, but there have been a lot of questions concerning the new 5.0L Ti-VCT, namely in regard to power adders.
MM&FF has been on the cutting edge of the 5.0L since its unveiling and we've tested quite a bit of parts and pieces over the past several months. This issue, we take one to the next level by bolting on a Paxton High Output supercharger system and chart the engine's new power. We also got a glimpse into the intricate tuning of the Copperhead PCM.
We made our way to JPC Racing where the shop's barrier-breaking '11 Mustang GT was stripped of its nitrous system in order to get the centrifugal supercharger bolted on. As much as we'd love to see JPC's Justin Burcham add spray on top of the boost, it wasn't going to happen this time around. The JPC team had modified the shop beater since we last saw it ("10s Too Easy," Sept. '10) by adding Kooks long-tube headers, Kooks 3-inch X-style mid-pipe with high-flow catalytic converters, and a wild new vinyl wrap. JPC also has a new in-house calibrator, Kevin MacDonald, and he's been working with prototype tuning software for the '11 Mustang from DiabloSport. The new mods had the car making 433 rwhp and running mid-11s in naturally aspirated trim. Burcham's goal was to have the supercharger on the car and tested before the Invitational MM&FF 5.0L Shootout, which you'll be reading about in next month's issue.
Mechanically speaking, bolting on the supercharger was the easy part since Paxton provided all of the parts and pieces. The kit includes the NOVI 2200 supercharger-a beast capable of over 1,000 hp (at the crankshaft). Thanks to the high compression, the engineers at Paxton have incorporated an air-to-air intercooler to keep detonation at bay. "The centrifugal boost curve fits the new engine nicely, it doesn't hit it with instantaneous boost and load the engine as hard as a positive-displacement blower would. This setup has a nice torque curve with the centrifugal power rush when you rev it out," stated Burcham. For pump gas applications, he'd limit boost to 6-8 psi for now and 10 psi for the weekend dragstrip warriors. Burcham would rather leave a margin for error until the team gains experience with the new engine and PCM.
The two main concerns with this article were the tuning solution and engine longevity. Would it hold up to the planned 10 psi of boost, and could MacDonald get it tuned in time for our deadline? Luckily, the answer was yes on both accounts.
But first, Macdonald had a daunting task ahead of himself.
"The new 5.0L Copperhead PCM brings a slew of changes and additions to Ford's existing calibration platform in the Spanish Oak (the outgoing Mustang computer). Although there is carryover strategy from previous years, it has become increasingly more complex," stated MacDonald. "The Copperhead now has to accommodate VCT on all four camshafts instead of two, utilizes a frequency-based MAF sensor, closed-loop fueling with wide-band oxygen sensors, and a mechanical return-less fuel system without a fuel-rail pressure sensor for feedback. The software is much more complicated."
The Mustang community has become jaded to a certain degree since tuning the previous generations of Mustang seems effortless for most shops. Now it's a bit more complicated-for the time being anyway. At the time of this writing, MacDonald was exploring strategies inside the black box that only a handful of people outside of Ford engineering have been in.
"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.