It's pretty much impossible to argue against the notion that innovation and Mustangs have enjoyed a hand-in-glove relationship for almost 30 years. As 'Stangs continue to evolve--from the EFI Fox-bodies that started the late-model phenomenon in the middle '80s to the S197s of today--aftermarket manufacturers are still developing products that are taking 'Stangs deeper and deeper into the high-performance stratosphere.
Hellion Power Systems of Albuquerque, New Mexico, is one of those companies. Led by multi-time NMRA Super Street Outlaw champion John "Do Work, Son!" Urist, Hellion has been considered a major force in the development of bolt-on turbocharger systems for late-model 'Stangs since entering the aftermarket back in 2000.
As a street-'Stang-enthusiast-turned-racing-champion, John knows all about the importance of "boulevard cred," and thus has focused his business on conceptualizing turbo systems that make big steam in cars that see daily usage more so than building setups for NMRA participants or other full-on race Mustangs.
Travis Franklin of Gear Heads...
Travis Franklin of Gear Heads Automotive and Performance checks the fitment of the Turbonetics low-mount, 61mm turbochargers that will make boost magic happen when they start feeding the factory supercharger in his '08 Shelby GT500. Travis picked up his low-mile, still-under-warranty Shelby for a song, and was 100-percent ready to set it up with Hellion Power Systems' Shelby GT500 Twin Turbo setup--a performance mod that is about as radical as they get right now for GT500s. Give that man the "ain't skeerd" badge he deserves!
The "Hell Raiser" system was Hellion's initial foray into the world of compound boost (turbos that work in conjunction with superchargers) for factory-blown Ponies. Designed for '03-'04 Cobras, the tricked-out turbo system is highlighted by a pair of Turbonetics 66mm units that blow boost directly into a Snake's blower, creating a multiplied air force that makes far more horsepower and torque (at low rpm) than a Terminator's supercharger is capable of making on its own.
Not to be funny, but we were blown away by the Hell Raiser setup when we saw it for the first time (the system was a unanimous "favorite-product-at-SEMA" selection by 5.0&SF's editors in 2006). The system is clean, innovative, and as we've learned from seeing cars that are outfitted with Hell Raisers, capable of taking a Snake's stock engine to the 1,000-rwhp level in a blink of an eye.
We'd never think of Terminators as being old news, but for the last two years, Shelby GT500s have been the hot ticket when it comes to factory-blown Ponies. With John constantly thinking of ways to make more power--even for cars that already have more than 400 rwhp--we knew it was only a matter of time before we'd hear that a compound-boost setup for the '07-present super 'Stangs would be created and available for us to check out.
John gave us the call in late 2008 and confidently described his latest creation as an all-inclusive, totally bolt-in, upgradable, no-cut (save for the OEM catalytic converters, which are eliminated from the exhaust system), no-weld, no-fabricate deal. He guaranteed it would easily put 700 horses at the feet of a stock Shelby GT500 'Stang, using only a pair of Turbonetics 61mm turbos and a GT500's OEM supercharger to get it done.
"The Shelby's blower is a positive-displacement device that basically takes air and makes it `smaller' by compressing it. Boost from our turbos actually help the supercharger compress and move air into the engine. The stock Roots blower really isn't as much of a restriction as people seem to think, and our Shelby GT500 Twin Turbo system proves this. Power under the curve is the big advantage of this system. There's no turbo lag, and compound boost literally can make unusable amounts of power for street GT500s with little effort," says John.
Claims of big-time rear-wheel horsepower coming easily through the addition of a single or combination of power adders certainly can be true. However, they're still the type of boasts that will quickly bury the needle on our "oh, really?!" meter, almost every time we hear them. With that said, we needed to personally satisfy our interest in the compound-boost setup for Shelbys, and, of course, let you all know what's up, right away.
 Ford sets Eaton's M112 Roots-style...  Ford sets Eaton's M112 Roots-style supercharger on top of the 5.4-liter engines that power Shelby GT500s. Our test 'Stang is stock as a rock; it will be interesting to see how it performs and stands up to compound boost. |  The first step and critical...  The first step and critical "mod" in installing Hellion's turbo system (after disconnecting the negative battery cable and safely mounting the Shelby on a twin-post hoist, of course) is cutting the exhaust tubes and doing away with the factory catalytic converters. That's right--the cats aren't used with this setup, so enthusiasts who fret over passing state vehicle inspections need not apply. |  Naturally, the aforementioned...  Naturally, the aforementioned Turbonetics 61mm turbochargers are at the head of the contents list for the Shelby GT500 Twin Turbo system ($5,599). However, as this photo shows, there are several mandrel-bent (to maintain strength), stainless-steel tubes essential for completing the compound-boost setup on a Shelby. In addition to the tubing, Hellion includes every bracket, shield, bolt, washer, nut, tube, hose, clamp, silicone coupler, fitting, pump, and wastegate required for installation. The company also offers a 66mm turbo upgrade ($1,190), dual-solenoid electronic boost controller ($595), and an optional secondary intercooler ($995) for those who really want to take their big-steam production to the next level. |
 Here is a closer look at the...  Here is a closer look at the system's primary "boost tubes," which are numbered and installed in a series. The tubes are the primary ducts that route the output of each turbo up to the mass-air meter and throttle body. |  The turbo-mount tubes--commonly...  The turbo-mount tubes--commonly referred to as up-pipes--bolt directly to the factory exhaust manifolds, which feed the hot side of each turbocharger. Note that clearances between the tubes, chassis, and transmission are tight, so there is a slight bit of finagling involved to get things properly seated and fastened, especially if you have big hands. |  Travis installs this adapter...  Travis installs this adapter log in the 5.4's oil-pressure-sensor location. The log has provisions for the sensor, as well as two AN fittings that will feed oil to each turbo to keep them cool and properly lubricated. |
 After hanging the turbos (on...  After hanging the turbos (on the up-pipes) and lightly securing them, Travis attaches the exhaust-discharge tubes (downpipes) to each huffer, using high-temp orange silicone to ensure tight, leak-free seals. The bolts around the exhaust and compressor housings on each turbo are left loose, allowing Travis to clock the turbos properly when the boost pipes are installed. When it's all said and done, there will only be -inch of clearance between the compressor housing and the Shelby's transmission. It's close, but it all fits. |  Two Turbonetics 38mm wastegates...  Two Turbonetics 38mm wastegates regulate boost for each turbo. The watsegates are outfitted with 9-psi springs at the factory. However, since Travis is also installing an optional electronic boost controller,... |  ... a set of 5-psi springs...  ... a set of 5-psi springs are swapped into each wastegate, giving Travis more flexibility to trim the boost output with the electronic device. With the smaller springs in place, we estimate the system's compounded boost pressure should be 15-16 psi at the intake manifold. |
 A small amount of bench work...  A small amount of bench work is required before the turbos can be hung. Oil-drain flanges (one of which is being installed in this photo), gaskets and 3/8-inch NPT fittings are included with the twin-turbo system, so there's no need to make a run for hardware in the middle of the install. |  Hellion offers a cool (pun...  Hellion offers a cool (pun definitely intended) secondary intercooler for the Shelby GT500 Twin Turbo system, which works as a support device for the blown-'Stang's factory intercooler and heat exchanger. Supercharger heat soak is probably one of the only unavoidable nuances for GT500s. According to John, the additional 'cooler is not used in series with the car's other OEM cooling. Instead, coolant for the secondary unit parallels the factory system. With this arrangement, water for both intercoolers maintains the same temperature and helps alleviate what would be a quicker advancing and longer lasting heat-soak condition. Using the supplied bracket and hardware, Travis installs the unit in a pocket behind the front bumper cover on the driver side, and then plumbs its coolant source and output (redirected from the factory heat exchanger) and inlet/discharge tubes for the fast-rushing air. |  All of the stainless boost...  All of the stainless boost tubes in the compound-boost setup are numbered and fit without modification. We dig the turbos' low-mount, stealth location. Airflow into each 'charger is filtered with small K&N air filters that fit along both sides of the transmission in small pockets at the front of the chassis (near the steering rack). |