June 1, 2013

When Ford made the switch to port fuel injection in 1986, many performance enthusiasts were ready to quit, claiming the new electronics (read: EFI) was going to kill the hobby by eliminating the verage gearhead's ability to change parts, tune, and consequently increase horsepower. Little did anyone know it would be those very electronics that allow us to reach ridiculous horsepower levels.

Who could have ever imagined Ford would produce a vehicle with a supercharger, 662 hp, and spot-on driveability? The current technology in our vehicle computers gives us, the end users, the ability to “tune” our engines, some of which make north of 1,000 hp and are streetable. Best of all, there are still mods that can be done in the home garage. Okay, there's no distributor or fuel pressure regulator to tweak, but you can still get (a little) dirty and work on your own Ford.

To prove this, we swapped out two common aftermarket parts that have become staples of Mustang performance—the throttle body and a plug-in tuning device, this time the SCT X3 Power Flash programmer ($379) and a Super Cobra Jet oval throttle body (suggested retail $679) from Ford Racing Performance Parts.

Our Deep Impact Blue tester is owned by winning NMRA-racer Jim Roberts and was in 100-percent stock trim when it arrived at our MM&FF Snap-on Tech Center in Tampa. Naturally, we baseline-tested the GT500, making five pulls. On the first few pulls, it made 612 (three times in a row) before spitting out a best of 619 rwhp once the fluids were up to temp.

Satisfied with the baseline numbers, we loaded the SCT tune, which was an over-the-counter tune, not custom. Associate Editor Marc Christ loaded the tune by plugging the unit into the OBD-II port and following the simple instructions. It takes a few minutes for the tune to load.

“This is our preloaded file for the 2013 GT500,” said Chris Johnson of SCT. “It changes commanded throttle, so basically it holds WOT longer. We adjusted spark advance and modified the air/fuel to make it slightly leaner at WOT from 10.5:1 to 11.0:1. In addition, we set the cooling fans to come on earlier, and we make the knock sensor more aggressive, meaning it can add in spark at a faster rate if [the sensor] doesn't hear knock.”

With the tune loaded, we made a few more pulls, and output increased from 619 to 647 rwhp, a gain of 28 rwhp. As a side note, we recorded 15 psi of boost.

Next up was the FRPP Super CJ Oval throttle body (PN M-9926-SCJ). Like the tune, installation was easy, requiring removal of the air-inlet tube, a few wiring connectors, and the stock twin-bore throttle body, which is held in place with four bolts. A flat-head screwdriver, and 10mm and 8mm sockets are all that's needed to complete the task.

With the polished FRPP TB in place and the inlet reinstalled, we made our pulls. Horsepower jumped again, as the new peak was 672 rwhp—a total gain (at peak horsepower) of 53 horsepower for just two simple mods that virtually anyone can do. We also noted a 1 psi increase in boost to 16 psi for most of the pull, and a peak of 17 psi.

With a little more foresight, we could have thrown in a cold-air inlet and found more power, as this is yet another simple mod that just may get your GT500 close to 700 rwhp. Overall, we were impressed with the gains. We can't wait to get this GT500 to the track to see what it can do.

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