Twin Turbos Blast the Ford GT up to 1,000 Horsepower Even under a 1,000-horsepower onslaught, the Ford GT remains flat and composed during acceleration. By John Pearley Huffman, Contributor Date posted: 04-15-2008 1,000 horsepower - 240-plus-mph top speed - 137-mph trap speed It looks like any everyday Ford GT, but John Hennessey says there's 1,000 horsepower under its rear deck. This is Hennessey Performance Engineering's twin-turbocharged GT1000 and it has just roared to life as if the gates to hell have blown open. Time for some hyperbole. Blipping the throttle has it pivoting over its keel like it's been hit by a tsunami. The sound is so intense, the shockwaves could be used for CPR. This car has the power to move continents and disrupt the very rotation of the earth. Then we drive it. And when the turbos hit it's as if the car has been grabbed by the gravitational pull of a black hole. Time, space and your facial features seem to warp into a frappe of subatomic particles. Four full digits' worth of power — it's the sort of thing that gives insanity a good name. Belts? We Don't Need No Stinkin' Belts! The Ford GT is already one of the world's great slalom rippers. The move to hard-compound Hoosier racing tires didn't help the performance. Driven moderately, the Hennessey GT will behave on public roads. But it's a car with a vicious edge that has to be respected at all times. Ford built the GT with a belt-driven, Eaton-made, Lysholm-type screw compressor heaving 12.5 pounds of boost into the all-aluminum DOHC 32-valve 5.4-liter V8. That was enough to produce 550 horsepower. Not bad. But more is more. And more is better. Hennessey replaces that supercharger with two massive Garrett ball-bearing turbochargers that swamp the engine with up to 19 pounds of boost through an air-to-water intercooler and Tial wastegates. All that compressed charge enters the engine through the monstrous maw of an Accufab CNC-machined billet throttle body that feeds a custom-fabricated intake manifold. Hennessey didn't have to touch the engine's internals or even remove the heads, but the fuel system has been upgraded to supply gushers of gas, the engine management software is full of fresh algorithms and an upgraded mass air sensor has been installed. And of course, the exhaust goes out through custom stainless-steel pipes. Hennessey retains the GT's stock Ricardo six-speed manual transaxle, but upgrades the bolts in the CV joints to handle the thrust. Running at 17 pounds of boost, Hennessey says the twin-turbo GT will rip the rollers of its chassis dyno to the tune of 870 hp at the rear wheels. Use any reasonable rule of thumb to account for drivetrain losses and this puts the car at almost exactly 1,000 hp, Hennessey claims. And if that's not enough, the wick can be turned up to 19 pounds and that number leaps to 920 hp at the rear wheels — which has to be near 1,100 hp. "Just run the tests with it on the low setting," John Hennessey wrote to us. "The high setting will likely have too much wheelspin." Geez, you think? And all Hennessey charges for the twin-turbo conversion is a mere $45,000. But that includes a one-year warranty — should you live that long. The Rush for the Horizon At first glance, the only indication that there are turbos aboard is the "Twin Turbo" lettering on the cam covers. Someone at Hennessey spends a lot of time polishing these things. In fact, the turbos are buried well behind the engine. The exhaust tips are beautiful. But it's the sound they emit that's truly epic. Turbos, particularly huge turbos like the ones on this car, need to spool up to produce boost. In the GT1000, that's not until the tach needle has swept past 5,000 rpm. And the Hennessey GT bogs down on hard launches if the dance between the clutch and accelerator isn't perfectly choreographed. But get the dance just right, and the Hennessey GT will rip to 60 mph in just 3.7 seconds and devour the quarter-mile in 11.2 seconds at 137 mph. Of course there's wheelspin in every gear, and if the car were tuned specifically for launches that 0-60 time would drop below 3 seconds and the quarter-mile would blow by in the mid-10s. Just look at that quarter-mile trap speed. That's 137 mph, a full 17 mph faster than what the epic R35 Nissan GT-R turned in for us during our full test. And it's 18.5 mph faster than the Porsche 911 Turbo. And it's a lot faster than the standard Ford GT we tested in our 2006 American Exotics Comparison test. That car rocked to 60 mph in 4.0 seconds and consumed the quarter-mile in 11.8 seconds at 125.9 mph. With its relatively narrow power band (Hennessey asked that we shift between 6,500 and 7,000 rpm during our tests — remember, the big power comes on at 5,000 rpm), the Hennessey GT is a much more narrowly focused car than the standard Ford GT. After all, Ford built the GT to be usable every day, even by those who never get to a racetrack. On the other hand, the Hennessey GT is built for events like the Texas Mile, where its raging acceleration from 100 mph to 200 mph can be used. What's the top end on this car? We simply didn't have the space to find out. But Hennessey claims "north of 240" mph. About the only way to make a Ford GT go any faster is to ship it in the belly of a 747. Fortified by Ford The Hoosier R6 is a silly tire for street use. And the brand-new ones on the Hennessey GT weren't treated to the specific and extensive break-in procedure recommended by their maker. For $6,500, Penske coil-over shocks replace the standard Ford GT units. Considering the comprehensive competence of the Ford GT, Hennessey didn't have to do much to upgrade the rest of the car to match the engine's output. The stock shocks and springs have been replaced with a Penske coil-over system (that's a $6,500 upgrade), and Hoosier R6 racing tires (255/40ZR18s up front and 315/40AR19s in back) have replaced the rubber. Before you go ordering up a set of Hoosier R6s for your commuter Camry, keep in mind that these are hard-core racing tires — essentially slicks — that are incompatible with any sort of moisture on the road. On the Tire Rack site, there's an admonition warning that reads, "It is unsafe to operate any Hoosier Racing Tire including DOT tires on public roads. The prohibited use of Hoosier Racing Tires on public roadways may result in loss of traction, unexpected loss of vehicle control or sudden loss of tire pressure, resulting in a vehicle crash and possibly injury or death." Then again, if you have a 1,000-hp car, you should already be comfortable with the idea of your own mortality. The one aesthetic modification to the Hennessey GT is the excision of the rear bumper and the installation of new panels to cover the holes. It does nothing but good for the GT's looks. Everyday Driver A GReddy boost controller is mounted on the dash beneath the passenger airbag to control the torrents of boost produced by the two turbochargers. The Ford GT is one of the most civilized supercars ever built. Around town it will trawl like a Taurus if it's asked to and the ride is stiff, but not so brutal as to shatter your coccyx. If it weren't for the GT's criminal lack of storage space, it would make a perfectly tolerable commuter. And kept below 4,000 rpm, the Hennessey GT is really not much different. It putters along at part throttle like a plumber's well-worn F-150 — just another corpuscle in America's traffic bloodstream. You can merge onto the freeway shifting at about 3,000 rpm, and the feeling of urgency isn't much different from, say, a Mustang GT. But terror lurks at 5,000 rpm when those turbos hit and then there isn't a freeway long enough or broad enough to contain it. And it sucks down fuel ferociously — you can almost hear the pumps in Saudi Arabia working harder to feed it. The Hoosier tires are best left on a racetrack where they can be kept boiling at temperatures where they're effective. Zigzagging furiously on the return to the start to keep heat in the tires resulted in one 70.2-mph run through the slalom, but otherwise, compared to the stock GT the Hennessey car is much more unsettled during less-than-extreme running. There was more understeer and the stiff sidewalls transmitted more road racket into the GT's structure. Braking was an expectedly excellent 103 feet from 60 mph to a dead stop. Fade? None. The Big Dig From this view, except for the "GT 1000" in the stripe, the Hennessey car is indistinguishable from other Ford GTs. Add everything up and the Hennessey GT is just about a quarter-million-dollar automobile — almost exactly the median price for a house in the United States. But for the person who's addicted to speed, this is one of the world's greatest thrill rides. It doesn't build speed with antiseptic competence like a Bugatti Veyron, and it has a merciless personality that speaks to some drivers' souls in a way a Nissan GT-R or Porsche Turbo can't. If you're the right person for this car — and since Hennessey is currently building his sixth GT, there are at least a half dozen of you out there — there's simply no substitute. There's really only one thing for you to do: Sell your house. Stand behind the Hennessey GT as it accelerates and you can feel the sound pound your chest like an L.A. County paramedic. And then there's the heat. What Works: Top-end acceleration that flattens time, space and corneas; full-immersion surround sound. What Needs Work: Grip-free launches, unforgiving tires, not much low-end torque, fuel economy that would shame a B-52 Bottom Line: Grip-free launches, unforgiving tires, not much low-end torque, fuel economy that would shame a B-52.