Drew Hardin Contributor
July 1, 2005

Horse Sense: The HPS turbo kit for '94-'04 Two-Valve Mustangs is not 50-state legal, but it may pass smog in other, less-restrictive states. A turbo kit under development for '05 Mustangs will be CARB-legal, says John Urist.

With the hood closed and the engine idling, Xhaust guru Darryl Bassani's '00 GT looks absolutely bone-stock. Other than the polished stainless exhaust tips, there's no external clue to the true nature of this basic black coupe. If you were to putt-putt around town with a light right foot, you'd be hard-pressed to notice anything unusual about the car.

That first freeway on-ramp, though, would wake you right up.

You see, when John Urist set out to build a street turbo-charger kit to offer through Hellion Power Systems, the word "street" was foremost in his planning. This is not a light-switch motor, with nothing down low and the jump to hyperspace coming only after the tach passes four grand. As John put it, "This is everything a street guy would want, and no more." Meaning: docile driveability when getting groceries, pin-you-in-your-seat acceleration when the hammer is down.

In our April issue, we showed you the HPS kit John built for his '91 LX ("Turbo Lover," p. 58); what you see here is a just-about-production-ready version of a similar kit for mod motors. John spent months prototyping the system, using Darryl's GT as his test mule, and the results are impressive.

For one thing, this is a true bolt-on system, with no welding or cutting required to complete the installation. The development time John spent on the system is readily evident in its extensive parts list. Every nut, bolt, bracket, spacer, and clamp you could possibly need is there, as are fuel injectors, a fuel pump, even spark plugs. The components are top-quality, too: Turbonetics turbocharger, silicone hoses, T-bolt clamps, and Bassani stainless-steel tubing. And unlike some other turbo installations, the HPS kit not only retains the stock A/C system, but also doesn't require a system recharge.

Fitting the turbo's plumbing under the car does require some modifications beyond the engine bay. To make room for the tubing, the car's stock K-member is replaced by a Granatelli Motorsports' tubular K-member, to which are bolted Granatelli control arms and coilovers. Yes, it adds to the complexity of the kit and its installation time but when all the work is done, the car owner will enjoy improved power and the ability to tune his Mustang's ride height and handling qualities.

How much power will the turbo produce? How does almost doubling the engine's stock output sound? While stock 4.6 Two-Valves dyno anywhere from 220 to 230 hp at the wheels, John designed his kit to produce "between 375 and 380 hp at the wheels when it's bolted to a stock engine. But you can crank it up to 500 horses or so if you have the right parts and the right tune" (See The Right Tune sidebar).

Recognizing that every customer's car and circumstances will be different, John opted to not sell a tune with his kit. "The best way to tune this kit is to go to your local dyno and have them work with you to burn a chip that's right for your car," he says. For those who want to do the tuning themselves, HPS can sell engine programming systems, such as the Anderson Ford Motorsport Programmable Management System seen here. If you don't live near a dyno and can't do the programming yourself, there is a third option: Shawn Ellis at SoCal Tuning & Performance programmed this car, and he can duplicate that for other HPS customers.

How close were John's power estimates? Turns out he underpromised and over-delivered. On the chassis dyno at Superior Automotive, the drums spun up to 387 hp at 4,400 rpm and 459 lb-ft of torque at 4,000. That's with a stock Two-Valve 4.6, 8 psi from the turbo, a mild chip, a Bassani 211/42-inch Aft-Cat exhaust system, a high-flow cat, and California's 91-octane premium fuel.

At $6,195, the HPS system is not inexpensive, but keep in mind that price includes not only the turbo kit, but also the K-member and suspension pieces. And really, that price isn't out of line when you consider the overall performance gains available with this system. Power and handling-an unbeatable combination.

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