I turn the key and the engine comes to life. The door closes, I pull the belts tight, and as I shift the transmission into First, the world seemingly goes quiet as my attention is consumed by the task ahead. A bead of sweat runs down my face as I roll into the burnout box. First gear. Second gear. Tire smoke consumes the back of the car, and as I release the brake, our Amsoil GT rolls out of the cloud it just created.
Inching towards the starting line, I stop at the hint of the pre-stage bulb. With my left foot planted on the brake pedal, I bring the revs up and bump the car into the staged position. The lights seemingly take forever to come down-as if they are moving in slow motion. Finally, I peel my foot from the brake and stand on the gas pedal just as the light flashes green.
In the next instant, the nose comes up a little and the rear tires dig in. The tach passes 7,400 rpm and the transmission violently shifts into Second gear. The whine of the supercharger and the scream of the exhaust fill the driver's compartment. There are two more shifts and I cross the stripe at close to 130 mph.
Wow! It's hard to believe that our AMSOIL Mustang GT has so few performance mods and is so bloody fun to drive. The rush of a mid-10-second quarter-mile pass is an amazing feeling, especially when you've taken the car from stock to its current state in your own garage.
The transformation of our Mustang from stock to showcar/racecar has been lengthy, but a fun and rewarding process nonetheless. After over seven months of anticipation, we finally hit the track. In our first outing, we laid down low-11-second quarter-mile times without really trying. Last month, we swapped the torque converter and changed the rearend gears. Although a lack of tuning and soupy Florida air didn't let us see the big gains we were hoping for, our 60-foot times were greatly reduced, which hinted that we were on the right track-literally.
This month we're at it again, and although we aren't going to spend a lot of time changing parts, we are going to dyno-tune the engine and trans, and then revisit the track. In our last installment, we headed to the Bradenton Motorsports Park without changing the tune for the parts we added. I know, I know-that's a no-no. But we were pressed for time, and it gave us a real A-to-B comparison. Well, now it's tuning time!
Justin Starkey of VMP Tuning...
Justin Starkey of VMP Tuning made the trip from Deland, Florida, to our Snap-on Tech Center in Tampa to handle the tuning of our AMSOIL ’11 Mustang GT. Starkey has tons of experience with the automatic-equipped ’11s. His supercharged Coyote-powered GT has gone a best e.t. of 9.79 at 140 mph.
The day started on our in-house Dynojet 224XLC chassis dyno. Justin Starkey, owner of VMP Tuning, made the trip from Deltona, Florida, to our Tampa Snap-on Tech Center to handle the changes to the calibration. Knowing we wanted to make more power and ultimately go faster, we called Whipple Superchargers, which produces the FRPP kit on our car, and ordered two smaller blower pulleys-a 3.125- and a 3.000-inch version. We also tapped JLT Performance for one of its Big Air cold-air intake systems for supercharged '11 GTs. JLT's Big Air kit fits all Roots or twin-screw supercharger systems for the '11 GT, with the exception of the Kenne Bell with a twin 75mm throttle body. By the time you read this, the kit will also be available in plastic as well as carbon fiber.
Follow along as we tune and track-test our AMSOIL Mustang GT, and check out www.musclemustang fastfords.com for exclusive video from both our Snap-on Tech Center and Bradenton Motorsports Park.
1 Starkey started by putting...
1 Starkey started by putting a baseline tune in the Copperhead ECU. Our starting number was 535 rwhp and 468 lb-ft of torque. He then went to work on the tune, and was able to manipulate 551 rwhp and 474 lb-ft of torque from our supercharged 5-liter.
2 Whipple Superchargers sent...
2 Whipple Superchargers sent us a pair of smaller diameter pulleys for our Ford Racing/Whipple twin-screw supercharger. When we started the day, our 2.3-liter Whipple was sporting a 3.337-inch blower pulley. Whipple sent us a 3.125- and a 3.000-inch pulley to raise boost levels.
3 Starkey made quick work...
3 Starkey made quick work of the pulley swaps.
4 With our base of 551 rwhp...
4 With our base of 551 rwhp and 474 lb-ft of torque in place, we spun the rollers again—this time with the 3.125-inch pulley on the blower. The smaller pulley made about 9 psi of boost (2 over our 7-psi baseline), which helped our GT make 583 rwhp and 498 lb-ft of torque. A gain of 32 rwhp and 24 lb-ft is definitely solid, but we wanted more. The 3.000-inch pulley made an addition pound of boost over the 3.125-inch pulley, which equated to 595 rwhp and 519 lb-ft of torque at 10 psi. This gave us a gain of 44 rwhp and 45 lb-ft of torque over the 3.337-inch pulley, and a gain of 12 rwhp and 21 lb-ft over the 3.125-inch pulley.
5 The next piece added in...
5 The next piece added in our quest for more power was JLT Performance’s carbon fiber Big Air cold-air intake system for supercharged ’11 Mustang GTs. The kit features a 127mm mass air housing, with a large reusable air filter that sits in a new airbox made from ABS plastic.
6a Starkey started by removing...
6a Starkey started by removing the stock cold-air intake...
6b ...The mass air sensor...
6b ...The mass air sensor is removed from the stock intake and slid into the JLT Big Air mass air housing.
7 Next, the new plastic airbox...
7 Next, the new plastic airbox slides in place where the stock airbox once sat. The new box attaches using one stock bolt and a nut supplied in the kit.
8 Starkey slides the carbon...
8 Starkey slides the carbon fiber mass air housing onto the throttle body. JLT tells us the Big Air kit will fit all Roots and twin-screw supercharger kits, with the exception of the Kenne Bell-equipped with a twin-57mm throttle body.
9 Starkey then went to work...
9 Starkey then went to work changing the tune for the new larger mass air housing.
10 Compared to our baseline,...
10 Compared to our baseline, the JLT Big Air kit was worth 28 rwhp and 5 lb-ft of torque over the stock airbox. The larger housing also gave an additional pound of boost over the stock intake system, which got us to 579 rwhp and 479 lb-ft or torque.
11 When we stepped up to...
11 When we stepped up to the smaller 3.125 pulley, the Big Air increased peak horsepower by 24 rwhp and 12 lb-ft as rwhp rose to 607 and torque jumped 510 lb-ft.
12 When the day was done,...
12 When the day was done, we picked up significant amounts of power from a pulley change and a cold-air intake swap. We started the day making 535 rwhp and 468 lb-ft of torque and ended the day at 607 rwhp and 510 lb-ft or torque, for an overall gain of 72 rwhp and 42 lb-ft of torque. Unfortunately at this point we ran out of fuel system and were forced to stop.
13 Following our tuning session,...
13 Following our tuning session, we headed to Bradenton Motorsports Park to see what our power gains would equate to on track. We started with the JLT Big Air intake and 3.337-inch pulley, which made 579 rwhp and 479 lb-ft of torque. We heated up the Nitto drag radials and headed to the line.
14 The car left hard and...
14 The car left hard and motored down track shifting firmly into each gear at 7,400 rpm. The short section of the track was covered in 1.59 seconds, and we were happy to see the scoreboard light up with our first 10-second pass—10.87 at 127 mph. After some time for the car to cool, we headed back out for another pass. This time tire spin slowed the 60-foot time to 1.68 seconds, but the e.t. picked up as we ran a 10.82, this time at 128 mph.
15 After giving the engine...
15 After giving the engine some time to cool, we went to work and swapped the JLT Big Air for the stock airbox. We also swapped the 3.337-inch blower pulley for the 3.000-inch version from Whipple. This combo laid down 595 rwhp and 519 lb-ft of torque, which was the most powerful combination without running the risk of a lean condition.
16 As the car rolled into...
16 As the car rolled into the burnout box, we were all hoping for a big number. When the lights went green, the car left hard. This was the only time all night we were able to match our best 60-foot of 1.59 seconds, only this time it did so spinning the tires. The car felt strong as made its way down track, and we were rewarded with a 10.65-second pass at 128 mph. Not only did we pick up 72 rwhp, but we dropped over half a second off our e.t. in the process.