As you pump away on the jack handle in order to swap the slicks on your GT500 for your street tires, you seethe with anger and a bruised ego. Here you are, thinking you're Billy Badass with your blown snake, and after a couple of runs at the test and tune, you end the night getting whooped by a tuned-up Z06. If you only had a little bit of extra power, that gold-chain-wearing punk wouldn't have been laughing while he took that $100 you laid down on the race. Just as you finish up, you swear that the next time you line up against that poser, you'll show him nothing but taillights.
Obviously, one of the easiest ways to make more power with a positive-displacement supercharged car is by switching pulleys. By doing so, you allow the blower to spin faster, thus creating more boost, which carries (if cooled properly) more available oxygen. This extra air can be countered with extra fuel, resulting in more power. Most times, 40-70 hp can result. The problem with spinning a Roots-style huffer like the stock Eaton M122 too fast is the resultant heat. The extra heat doesn't lead to as dense of an air charge, which leads to less power and, in some cases-if the proper fuel isn't used or the tune isn't spot on-detonation and a really big bang.
For those looking for big power, a supercharger swap is at the top of the to-do list. There are a number of different options when it comes to upgrading your supercharger, whether it's going with a larger Roots-style blower, a ported stock blower, or swapping over to a twin-screw. Add in the myriad of companies and the different size blowers, and you can see that there are a lot of decisions that need to be made.
 we just had to try out the...  we just had to try out the new TVS supercharger from Eaton, which is included in the Ford Racing Performance Parts supercharger upgrade kit for the GT500. The result was some serious tire-spinning power. |  Our test subject was Jimmy...  Our test subject was Jimmy LaRocca's '07 Shelby GT500. The car was in as-delivered condition, which meant the stock Eaton M122 Fifth-Generation supercharger was still sitting atop the 5.4L Four-Valve mod motor. |  The stock blower is good for...  The stock blower is good for some great power numbers, but we wanted more. With that in mind, we set out to rip this little huffer off and slap on its refined brother, the TVS. |
The New Kid On The Block Meets An Old Hat
One of the newest superchargers to come along is the Eaton TVS blower. Officially released in February 2007, the TVS (Twin Vortices Series) is a different design than the M122 blower found on top of the GT500, which is Eaton's Fifth-Generation supercharger. The TVS features twin four-lobe rotors that are twisted 160 degrees. This is completely different than the M122's lobe construction that showcases three lobes angled at 60 degrees. This fourth lobe and increased angle serves to create a more efficient flow into the engine when combined with the TVS' revised inlet and outlet ports.
With that in mind, we decided to get on the bandwagon and see just what a TVS blower swap on a GT500 could do in terms of power, both on the dyno and on the track. Our first and only call was to Mustang racing legend Jimmy LaRocca, who has piloted just about everything, from fast street cars to seven-second heads-up Pro cars. He picked up a GT500 of his own recently and was looking to make some astounding power. "I went with the TVS blower because I wanted to stay with an Eaton product as well as an over-the-counter Ford part," LaRocca explains as to why he chose the TVS blower.
"The TVS is really designed for the GT500, in my opinion," he says. "It fits under the strut tower brace, carries a warranty from Ford, and gives you plenty of room to grow, power-wise." When it came time to swap the blowers, to say it was a piece of cake would be an understatement. "The GT500 is generally an easy car to work on," LaRocca says. "This kit, though, is so simple. It's very straightforward, and you don't have to drain any kind of fluid. In all of my years working on Mustangs, and of all the installs I have done, this was, by far, the easiest I have ever performed. If it wasn't for you guys stopping me to take photos, I could have finished the install inside of an hour."
 With LaRocca spinning the...  With LaRocca spinning the wrenches, we started on the quest to answer our question of what the TVS could do for the Shelby. LaRocca started by disconnecting the battery and removing the blower belt. |  Larocca's son, Jimmy, removed...  Larocca's son, Jimmy, removed the strut tower brace. The installation of the TVS was so easy, a kid could do it. |  The MAF sensor and inlet tube...  The MAF sensor and inlet tube were removed, followed by the disconnection of all the other needed clips and connectors. |
 With the inlet tube removed,...  With the inlet tube removed, you can see the stock, dual-blade throttle body. While this throttle body is good for the way the kit is configured, according to Justin Starkey of VMP Tuning, it becomes a restriction above 550 rwhp. |  The next piece to be removed...  The next piece to be removed was the throt-tle body. |  The stock airbox was deep-sixed...  The stock airbox was deep-sixed next. The kit comes with an open-element box with a high-flow filter. |