Fox Turbo Upgrade - Sleeper Hit

With the install tasks handled, we fired up the freshly turbocharged 'Stang for the first time and took in the sound of a dramatically different exhaust note. Despite having a straight-through/open exhaust-Ricardo was undecided on mufflers at dyno time-the 'Stang's engine sounded much quieter at idle than it did in naturally aspirated trim.

Jimmy set fuel pressure at HP's recommended 27 psi, and Ricardo locked timing out at 16 degrees total. The Autolite 24s were gapped at 0.030 and a fresh batch of California's 91-octane pump gas was loaded in the tank for our dyno tests.

We were all curious to see how the Mustang's stock auto trans and torque converter would react to the influence of increased power and torque. Jimmy says most five-speed and AOD turbo 'Stangs are in boost by 2,900-3,000 rpm on the street. Since we're testing on the dyno and have to start our pulls in Third gear, we won't see boost until about 3,300 rpm, and there may not be enough time for the turbo to achieve full boost before the run time expires. While we realized there might be a few horsepower left on the table because of this, we forged ahead with our evaluation.

The result of the first dyno hit was a pleasant surprise. Our automatic 'Stang put 361 hp and a stellar 446 lb-ft of torque down on the dyno, and the tranny didn't miss a beat. That's a 185hp increase over our baseline with 209.48 lb-ft of additional torque.

Although this early showing was phenomenal, the dyno graph exposed a distinct break in the power and torque curves at 4,400 rpm and a full 9 psi of boost. After brainstorming, it was determined that spark was being blown out inside the cylinders, and we needed to address that issue right away if we wanted to continue testing with any more success. The data doesn't lie. It was obvious there was more power and torque to be made as long as the transmission hung in there.

We secured a new MSD 6AL unit, thanks to the efforts of Extreme Speed and Peterson Performance of Upland, California. GTR had one of MSD's plug-and-play harnesses for the ignition box (PN 8874), and Jimmy had everything connected in a hurry.

For our final hit, we decided to see how more timing and closing the spark-plug gap to 0.027 would work in conjunction with the enhanced spark provided by the MSD. We'll let the numbers speak for themselves from this point, but if we had to sum up our opinion of the impact an HP Performance turbocharger has on a daily driven, 5.0-powered, automatic Fox in one word, that word would be "whoa!" Check out the video on our Web site www.50mustangandsuperfords.com.

With timing locked out at...        read full caption With timing locked out at 16 degrees, a fresh set of Autolite 24s gapped at 0.030 in place, and plenty of 91-octane fuel to do some testing within the tank, we strapped Ricardo's GT onto the rollers of GTR's Dynojet chassis dyno and put HP Performance's Fox-Mustang turbo system to the test.

Tech Editor KJ Jones said...        read full caption Tech Editor KJ Jones said the three magic letters-"M-S-D"-when we discovered the turbo was blowing out the candles at 4,400 rpm in our dyno runs. After an unsuccessful effort to locate a Digital 6, we were able to procure a new 6AL unit, thanks to the crew at Extreme Speed and Don Peterson of Peterson's Performance

HP Performance's co-owner,...        read full caption HP Performance's co-owner, Jimmy Hittle, called this one. He told us the Fox system would make roughly 9 psi of boost with fuel pressure and timing calibrations being the only adjustments made after completing the installation. Honestly, after watching the turbo do its thing, 9 psi came way too easily. It leaves us wondering what the power output will be when the needle rolls past 15 psi with the same 60mm turbo. The Fox system can be upgraded to turbos as large as 88mm.