From the July 1999 issue of Car and Driver.
Explaining the appeal of extremely powerful cars to nonenthusiasts can be like trying to explain sex to a three-year-old. “Why in the world would you need so much power?” they ask. If you have to ask, well, you’ll probably never understand.
Some cars that grace our parking lot, though, leave us almost asking the same question. Dodge Viper Venoms from Houston-based Hennessey Motorsports come to mind. HMS Venoms we’ve tested, packed with 550 or more horsepower, could rocket to 60 mph in well under four seconds and could top out at nearly 200 mph. For street-legal machinery, that’s outlandish speed. Use such capability often on public roads, and your license wouldn’t be the only thing you would be putting in jeopardy.
This dilemma is one reason HMS owner John Hennessey developed the Venom 650R. Like the Porsche RSR in Europe, it’s a sports car intended for the racetrack that just happens to be street legal. Hennessey got the idea for the 650R from attending some “Viper Days” club races. These increasingly popular events, which include a driving school for novices, are now held in conjunction with a series sponsored by Michelin called the Viper Challenge. Some of Hennessey’s customers at these events expressed interest in a purpose-built Viper race car that’s cheaper than Dodge’s factory-built $325,000 Viper GTS-R. The Venom 650R is Hennessey’s answer.
As with HMS street cars, the engine is the heart of the 650R. After disassembly, the crankshaft is reground with a 4.03-inch stroke, and the cylinders are rebored to an equivalent dimension, yielding a displacement of 8424 cc—nearly half a liter more displacement than the stock V-10. The block is restuffed with forged steel connecting rods, forged aluminum pistons, and a revised camshaft, and the heads are ported, polished, and fitted with a heavy-duty valvetrain. Feeding those heads is a Hennessey low-restriction airbox with K & N filters, 70 mm throttle bodies, and a ported and polished stock intake manifold. Aft of the engine are 1.75-inch HMS stainless-steel headers dumping into twin 3.0-inch HMS stainless exhausts. For these modifications, HMS charges $37,500, but that sum doesn’t complete our 650R’s driveline. There’s also an aluminum flywheel for $1500 and an aluminum radiator upgrade that goes for a similar amount.
On Hennessey’s Dynojet dynamometer, this balanced-and-blueprinted concoction rings up 583 horsepower and 585 pound-feet of torque at the rear wheels, which translates to about 670 horsepower and 673 pound-feet at the flywheel. The stock V-10’s 450 horsepower and 490 pound-feet seem almost mild in comparison.
With such bodacious power, this Viper is capable of spending more time at higher speeds. Aerodynamics questions this may pose are answered by the 650R’s “VenomAero” body package, which Hennessey says he spent more than $100,000 developing with the help of race-car designer Steve Everett. It consists of a front fascia with brake cooling ducts, a rear bumper with an underbody air diffuser, and a rear wing. In fiberglass, it’s $12,500, and in the lighter carbon fiber on our tester, it’s $20,000. Hennessey claims the wing generates about 100 pounds of rear downforce at 130 mph, and the new schnoz adds about 200 pounds up front (when a removable three-inch carbon-fiber lip is installed). These numbers were determined at speed using a Pi data-acquisition system that monitored front and rear suspension compression.
For $6500, the suspension sports Penske adjustable shocks with Hypercoil springs at all four corners that lower ride height by 2.0 inches in the front and 1.5 inches in the rear. A power-steering-cooler upgrade is $800. There’s also a $12,000 Brembo racing brake package with massive 13-inch discs gripped by four-piston calipers front and rear. Another $5000 buys custom HMS polished alloy wheels. They’re wrapped with $1500 Hoosier racing rubber, 275/35ZR-18 in the front and 335/35ZR-18 in the rear.
Typical racing accouterments wrap up the package. Inside are $3400 of Sparco racing seats with Simpson five-point harnesses. A Halon fire extinguisher adds $200 and mounts to a four-point roll bar ($1500). A short-throw HMS shifter for $300 tightens the H-pattern. For visual stimulation, Hennessey adds $950 of carbon-fiber instrument bezels and finishes off the entire beast in clear-coated Plymouth Prowler yellow for $6500.
No race-car transformation would be complete without a diet. Aside from the lighter body parts, seats, and flywheel, Hennessey removes the hood hinges, the spare tire, and the air-conditioning system. Our test car weighed in at 3271 pounds, which is 139 pounds less than the Viper GTS in our July 1997 supercar comparison.
With such lean muscle, the Venom takes easily to the track. In the straightaway, it explodes out of the hole, grabbing 60 mph in 3.4 seconds and the quarter-mile in 11.3 seconds at 129 mph. Its blistering 207-mph top speed, though, comes with an asterisk—Hennessey removed the drag-inducing rear wing, windshield wipers, and side-view mirrors for that test. Figure more like 200 mph with those items installed. Our car also had the catalysts removed for all testing—including the dyno run—as they would be for racing, claims Hennessey. Fair enough.
We won’t fuss over the rest of the 650R’s performance. Cornering grip is a neck-straining 1.04 g’s. Braking from 70 mph requires just 143 feet. That’s 34 fewer feet than in the last Viper GTS we tested. In fact, it’s the shortest stopping distance of any street-legal car we’ve ever tested. That’s without ABS, too.
On a road course, it works marvelously. The steering, which is distracted on the street, gains composure and precision at speed. The brakes scrub off triple-digit speeds with excellent feel and balance. As we exit the corners, the big V-10 shoves our posterior firmly into the Sparco. With little practice and one passenger on board, we managed to lap DaimlerChrysler’s proving-ground handling course in 1 minute and 12 seconds. Our best time in a stock GTS with ample practice (and no passengers) was 1:13.
As a street car, the 650R barely qualifies. The nearly open exhaust is so loud, you’re noticed everywhere you go; even puttering drives around town turn into a kind of psychological torture. Quieter mufflers that cost a few horsepower are available from HMS.
One more thing. Take the 650R plunge, and you’ll also get one free day of instruction at the Justin Bell Viper Driving School at Moroso Motorsports Park in Florida. Free is a relative term here. Add up that tab, not forgetting the $74,081 price of a new Viper GTS donor, and you’re looking at $173,031 for our 650R test car.
Figure that’s the cost of justifying to your slow-poke friends why you need all that power.
Specifications
Specifications
1999 Hennessey Venom 65R
Vehicle Type: front-engine, rear-wheel-drive, 2-passenger, 2-door coupe
PRICE
Base/As Tested: $165,581/$173,031
(base price includes all performance-enhancing options)
ENGINE
pushrod 20-valve V-10, aluminum block and heads, port fuel injection
Displacement: 514 in3, 8424 cm3
Power: 670 hp @ 5800 rpm
Torque: 673 lb-ft @ 4600 rpm
TRANSMISSION
6-speed manual
DIMENSIONS
Wheelbase: 96.2 in
Length: 175.1 in
Curb Weight: 3271 lb
C/D TEST RESULTS
60 mph: 3.4 sec
100 mph: 7.1 sec
1/4-Mile: 11.4 sec @ 129 mph
130 mph: 11.6 sec
150 mph: 16.7 sec
170 mph: 24.0 sec
Rolling Start, 5–60 mph: 4.3 sec
Top Speed (drag ltd): 207 mph*
Braking, 70–0 mph: 143 ft
Roadholding, 300-ft Skidpad: 1.04 g
*With windshield wipers, side-view mirrors, and rear wing removed and with smaller 17-inch wheels and tires fitted.
C/D FUEL ECONOMY
Observed: 12 mpg
C/D TESTING EXPLAINED