Automatic 2011 Ford Mustang GT Horsepower Test - Automatic Weapon - Tech

The '11 Mustang GT with the 5.0L engine is everything we hoped it would be. It packs a 412hp 5.0, has a great sound, and is a great performer in factory trim. In the past six months, we've seen these cars eclipse the 10-second barrier with nothing more than bolt-ons ("10s Too Easy," Sept. '10), and one guy ran 9s with a serious nitrous combo and a C4 transmission.

Despite this, the 5.0L Ti-VCT engine is still young, and the aftermarket is ramping up quickly to supply parts for it. One company in the driver's seat is AmericanMuscle.com. The company is a serious player, known mainly as a mail-order warehouse, but the recent addition of Bama Custom Tuning to the family moves it into the tuning and building market as well.

The company picked up a new 5.0L GT, not just for fun but as a means to learn and develop parts for the new-generation hot rod. The first wave of performance shows the potential of the 5.0L, but we noticed that most shops opted for the six-speed manual transmission. Would the automatic perform as admirably as its manual brethren?

AmericanMuscle was willing to find out with its purchase, a Grabber Blue '11 5.0L armed with the new 6R80 auto transmission. "We decided to get an automatic 5.0L because we had to learn more about the car for our customers," stated Chris Rose of AmericanMuscle. Along the way, the Bama Custom Tuning division worked with SCT to unlock the automatic shifting controls-more on that later. The goal was (and still is) to bolt-on the popular upgrades and chart the progress step-by-step so when a customer inquires about a particular component, the AmericanMuscle representatives will know exactly how the parts perform and fit.

Before any parts were changed or the computer was tuned, AmericanMuscle set out to get baselines on the in-house chassis dyno and on the drag strip at Maple Grove Raceway near Reading, Pennsylvania. In stock trim, the GT unleashed a 13.02 at 110 mph and 13.03 at 109 mph with Bama Custom Tuning's Mike Wilson at the helm. Back at AM headquarters, the car was hooked up to the Dynapack chassis dyno (a DynoJet will be installed by the time you read this issue). The in-house dyno is used to develop tuning files and randomly test parts and pieces from various manufacturers. The test mule produced 363 rwhp and 331 lb-ft; pretty much what is expected from an auto-backed 5.0L.

The dyno results are interesting with a 6R80 automatic car, to say the least. The new transmission lacks a 1:1 gear ratio, which is the traditional gear to used for dyno testing. The closest gear ratio in the 6R80 is Fourth, with a 1.14:1 ratio, and that is what AmericanMuscle used for its baseline dyno testing. Some shops use Third gear due to the 1.52:1 ratio. The team did determine that the more accurate technique to dyno test with the 4.10s, however, is to run the car in Fifth gear as opposed to the Fourth gear dyno pulls with the stock 3.15s.

One note for on-track racing-there is no Overdrive On/Off button. The Tow/Haul button is useless on the track because the computer switches to a tune table that kills performance. The stock 3.15 gears work well as the transmission stays in Fourth through the traps. But once you go to something steeper, like 4.10:1 gears, then the transmission will shift into Fifth to make it through the quarter-mile, thus killing performance. That problem is easily fixed in the aftermarket tune, and Bama set this car to stay locked in Fourth gear at WOT.

Once the baselines were consistent, it was time to raid AM's 115,000-square-foot warehouse for the latest parts and goodies. It's common practice for AmericanMuscle to randomly pick parts off the warehouse shelves and bolt 'em on an in-house test mule or an employee's Mustang. This is done across Mustang generations to ensure consistent quality and fitment of the product lines. Thankfully, many of the suspension modifications transferred over to the '11 platform with little to no issues. As for the power department, the traditional modifications, like the new ECU tune, larger exhaust, and cold-air intake, are all-new designs for the '11 Stang.

AmericanMuscle, through Bama Custom Tuning, works closely with SCT and was one of the first to get the tuning software for the new Copperhead computer system utilized by the '11 Stang. Three tunes were developed and are currently available for 5.0L Stangs. Like all SCT tuners purchased from AmericanMuscle, the tunes were labeled Street, Performance, and Race. Each is designed for pump gas and builds on each in terms of performance.

The Street tune is emission-compliant and offers better throttle response (but not sensitive like the Race tune), reworked air/fuel ratio for more power, and increased timing. According to Rose, the emphasis is on light-to-light performance and fuel economy. Moving to the Performance setting, the tune is similar to Street, but features a more sensitive pedal feel, much firmer and faster shifting for automatic cars, and a little more power, but it's still emission friendly and fuel economy-minded.

The Race tune is what the AmericanMuscle guys ran in the 5.0L on these pages. It's off-road only but still street-friendly as the shifts are much firmer and higher for automatic cars. It offers more aggressive air/fuel ratio and timing, and the drive-by-wire pedal feel is aggressive. It's usually the setting most people run full-time and engine longevity is not effected. We also like that Bama Custom Tuning offers free tunes for life after the initial purchase-no matter what the modifications or where those new parts were bought.

The fun didn't stop with the SCT X3 ECU mods; the team received one of the first MagnaFlow exhaust systems. It features a 3-inch X-style midpipe, sans catalytic converters, regulating it to off-road use only, and MagnaFlow's 3-inch Competition after-cat exhaust system. Underhood a C&L cold-air intake system replaced the stock airbox. The cold-air is similar to previous generations, but there are two different part numbers for 5.0L Ti-VCT engines, one for manual transmissions and one for automatic boxes. In this trim, the Grabber Blue Stang spun the dyno to 401 rwhp and 380 lb-ft torque. It was a healthy gain for the minimum set of modifications.

The path to fast times didn't stop there as the new-found power demanded attention in the traction department. First on the list were stickier rear meats; Nitto 555 tires were tapped for the task. The Nitto rubber was mounted on AmericanMuscle 18-inch Bullitt-style wheels. Helping plant the rubber are J&M Xtreme upper and lower control arms and adjustable Panhard bar, Eibach Pro-Kit springs, Tokico D-Spec adjustable shocks and struts, Ford Racing 4.10:1 gears, and a prototype Axle Exchange one-piece aluminum driveshaft.

All the suspension/driveline parts, save for the Axle Exchange driveshaft, were designed for '05-'10 use, and modifications were needed to make them fit. Rose tells us that the manufacturers claim the parts will be 2011 specific by the time this issue hits the newsstands. The '11 cars utilize a thicker upper control arm bracket and bolt, and AmericanMuscle fabricated a steel bushing to mount the J&M arm. The Tokico D-Spec struts fit nicely, save for the adjuster nut hitting the hood. A 1/8-inch spacer was fitted into the tower cup to prevent interference.

On track, the car responded positively with a new best time of 12.20 at 114 mph. The driving technique was to launch at around 1,000 rpm and roll into the throttle. A swap to Nitto NT05R tires (on the same 18-inch wheels) was a major improvement as the car could leave at 1,800 rpm, enabling better 60-foot clockings and quicker times. The NT05R tires helped the car run its best time to date, a 12.08 at 115 mph with a 1.90 60-foot. The team did manage to cut a 1.88 60-foot but ran into some troubles with the shifting.

Development is an ongoing event with the new 5.0L as parts are coming to the market quickly and there is still a lot to learn. When AmericanMuscle embarked on its mission to run in the 11s with bolt-ons and a street-style wheel/tire package, the SCT software was in its infantile stages. That meant the automatic transmission functions were barely modified in the early tune-ups when the team ran 12.08.

The problem was that if the tires spun enough, the ECU would put the transmission into a limp mode. This limp mode would kill the run by approximately 3-tenths of a second. The transmission would shift cleanly into Third gear and that is when the limp mode takes affect. Instead of going into Fourth, the transmission would shift back into Second and then quickly into Fourth. But that event only happened when there was noticeable tire spin at launch.

Thankfully, AmericanMuscle's tunes for automatic cars have since been modified for proper shifting thanks to SCT's efforts to crack into the transmission controls. An aftermarket tune will solve your problem if your stock or near-stock car exhibits some strange shifting problems on the dragstrip.

As of this writing, there is a Zex nitrous system plumbed into the massive C&L inlet tube, but it has remained dormant. The plan is to run the car on the jug after the new DynoJet chassis dyno is installed so proper testing can be done. The shop also plans on adding full-length headers, a looser torque converter, Mickey Thompson slicks, and Bogart racing wheels at all four corners. The goal is to run deep into the 11s in naturally aspirated trim and then launch solidly into the 10s on the spray. And it's not for fun but merely for the sake of research-wink, wink.