Steve Turner
Former Editor, 5.0 Mustang & Super Fords
May 29, 2012

No matter what product you buy, a better product is sure to supplant it. Buy a new computer, there will be a faster one. Buy a new TV, there will be a bigger one. Buy a new phone and there will be a cooler one. Cars are no different. Even if you buy a top-of-the-heap car like a Shelby GT500 with the Performance Pack, you aren't safe from buyer's remorse.

As awesome as the '11-'12 GT500s are, the announcement of the 650hp '13 GT500 delivered a strong message. You have two choices. Sell your GT500, or upgrade it. The former requires taking a large financial hit, while the latter will only cost you a bit more. Besides, you've been wanting to upgrade anyway.

In the case of Rick Schmidt of National Parts Depot, he is one of the few guys that calls his Performance Pack '11 Shelby GT500 a daily driver. With a factory glass roof, silver paint, and stripe delete, it's exactly the car your author would have ordered. It is a great car, but after piling up the miles, Rick was ready to add some ponies without detracting from the car's driveability.

With that in mind, Rick turned to VMP Tuning for one of Justin Starkey's TVS supercharger upgrade kits. Having already experienced the results of Justin's tuning and pulley upgrades on his otherwise-stock GT500, Rick knew that Justin has an effective recipe. Moving up from the stock blower to the TVS was the next logical step.

"The VMP TVS is built to my specs at the time of manufacture and includes a 12-month warranty. Those specs include a specially machined nose drive for the included 2.5-inch pulley. This is worth about 1 pound more than a regular TVS, which will only take a 2.6-inch pulley," explained VMP's main man, Justin Starkey. "The inlet of my VMP TVS is CNC ported and about 20-percent larger than the regular TVS, and it is matched to the high-flow inlet elbow..."

In the end, the dyno results were quite impressive, but even more impressive was Rick's impression of the car.

"It's a tale of two extremes, only now the two extremes reside in separate solar systems. Driven normally, the car behaves just as nice and docile and drivable as it was stock... But step into it past half-throttle and the car is an absolute gorilla," Rick enthused. "I honestly can't remember what it ‘felt like' before. I had thought the car was fast stock, but now it's a far more serious and g-force–experiencing prospect when you mash the throttle. Only in the right conditions can I get Third gear to hook whatsoever, and when it does, it's like riding a rocket."

Keep reading to see just how easy it is to completely transform your GT500's performance.

Horse Sense: Terminator owners needn't be jealous of all the GT500 upgrade options any longer. VMP recently introduced a TVS supercharger upgrade for the '03-'04 Cobra. It's available for $3,499 with a stock-style inlet elbow, or $3,549 with a single-blade inlet. VMP says this kit delivers as much as a 300hp gain on an otherwise-stock Termi.

On the Dyno

We've been around our share of aftermarket-supercharged GT500s, including our own Project Vapor Trail, so we know what to expect. That said, even we were impressed by the stout 136 hp and 129 lb-ft peak gains we saw on Rick's stock-exhaust car. We saw these on a mild day, but it wasn't really cold and the barometric pressure was pretty average. This was just a legit, healthy gain.

Of course, there was more than just a peak gain with this mod, the VMP TVS delivered solid gains throughout the power curve.

"Rick's car is well broken in and picked up right around what I would expect," Justin said. "The stock cats are raising boost by about 0.5 to 1 psi. With the addition of an off-road pipe, this car would probably see around 15-20 rwhp; something like Dynatech 17?8-inch longtubes would probably net 25-40 rwhp."

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