LaRocca is referring to the Ford Racing Performance Parts (FRPP) '05-'08 SVT Mustang Supercharger Upgrade Kit (PN M-6066-SGT). It's billed to increase power on a stock GT500 by 105 hp, and comes complete with a 2.3L TVS supercharger, an open-element cold-air intake system, a Pro-Cal tuner voucher, with which you can redeem the programmer for the kit with a tune from FRPP, and everything else needed for the installation. To get a true apples-to-apples comparison between the stock Eaton supercharger and the new TVS, the only thing we changed on LaRocca's Mustang was the blower.
Of course, we had to check out some before-and-after dyno numbers to see what the TVS did in terms of a power increase. In bone-stock trim, LaRocca's Shelby recorded 444 rwhp and 438 rwtq, which, considering the 500 flywheel horsepower rating from the factory, is quite respectable. After we swapped on the TVS, we strapped the snake to the dyno, ran it up to operating temperature, and flat-footed the accelerator. At 6,200 rpm, we cut off the dyno pull and waited for the computer to spit out the figures. Not that we were surprised, but Ford's advertised power figure of 605 was right on the money, as LaRocca's ride ripped off a rear-wheel power number of 605, with torque at a thundering 578 lb-ft. That's an increase of 161 rwhp and 133 lb-ft of torque. Not too shabby!
With the swap and dyno test complete, we made our way to the track to see just what this Shelby could do in the real world.
Being careful not to spill...
Being careful not to spill fuel, LaRocca removed the fuel rails, then disconnected the fuel injectors.
The intake plenum was pulled...
The intake plenum was pulled off of the mouth of the stock blower.
Timed To Perfection
While we didn't have a chance to baseline LaRocca's snake, we glanced back in the MM&FF archives at the "Bolt-On Bonanza" series we did with a Shelby GT500, starting with the Feb. '07 issue. In that article, MM&FF test pilot Evan Smith ripped off a 12.38 at 115 mph with a bone-stock GT500. This was with the stock Eaton M122 blower stuffing the 5.4L mod monster with 9 psi of boost. With that in mind, Editor Smith slipped behind the wheel of LaRocca's snake, fired up the beast, and throughout our day at Old Bridge Township Raceway Park in Englishtown, New Jersey, made a total of five runs. The result? How about an 11.77 at 121 mph. LaRocca said it best when he stated that the 11.77 was "a good run on a bad day." Keep in mind this was at 11 psi of boost, and the rest of the car was still stock, with the blower, its stock pulley, and the FRPP-supplied tune being the only additions. That's an e.t. drop of 0.610 second and a speed increase of 6 mph that came on a day where the air conditions were the consistency of New England clam chowder. In good air, this car could dip well into the low-11-second zone. That's just with the addition of the blower kit, folks. While LaRocca didn't change anything else, there are those out there who have taken the TVS blower to the next level.
Tune Time
With the FRPP TVS kit coming with a voucher to redeem a Pro-Cal programmer loaded with a Ford-derived tune, there are those who want to keep the Ford tune, and others who want to stretch things to the maximum. LaRocca's mindset is of the former, while Justin Starkey of VMP Tuning is one of the guys who goes to the brink.
"I haven't changed the pulley, and, personally, I don't want to," LaRocca says. "I don't want 12-13 psi or more of boost because at that point, the car, at that boost level, isn't practical. You have to worry about what type of fuel you run. I don't want to have a car that needs to run race gas.
"I don't want to push anything with this car. This blower doesn't take the reliability or comfort away from the vehicle. That's one of the main reasons why I picked it. I think a lot of people forget that they have to look at the whole picture and not just race the dyno. The engine has a lot of life in it. I mean, if Ford is willing to warranty a part that will allow it to make 600 hp, then you know the motor can take a lot." The question is, how much? As is the case with every custom-tuned forced-induction setup, be it the TVS or a twin-screw blower, having the tune spot-on is critical to longevity and power production.
Did you eat your Wheaties...
Did you eat your Wheaties this morning? After loosening up the blower bolts, the blower was lifted off and set aside.
You can see the differences...
You can see the differences in the case of the TVS blower (top) and the stock M122 (bottom). The snout on the TVS is different, and the blower's much larger outlet port is refined for greater flow.
The obvious difference between...
The obvious difference between the rotor profiles can be seen here. The TVS blower on the right has a four-lobe rotor combination, angled at 160 degrees. Compare this to the stock M122's rotors on the left, which feature three lobes on the rotor and a 60-degree angle. The result is that the TVS stuffs in more air with much more efficiency.
Another difference between...
Another difference between the M122 and the TVS is the TVS' revised inlet port.
Now for the meat and potatoes...
Now for the meat and potatoes of the install. The TVS blower was laid down onto the existing intake manifold and tightened down. The blower bolts are torqued to 25 Newton meters, or 20 ft-lb.