The Motown Musclecar War is Back
In Detroit this year, the North American International Auto Show recorded its 100th anniversary, and the city joined in on the celebration as the domestic automakers hogged the spotlight. General Motors won both the Car and Truck of the Year awards with the Saturn Aura and Chevrolet Silverado-the first time in history that one manufacturer swept both categories. Ford and Chrysler generated plenty of attention with their new hardware as well. It was a very good show for Detroit, in Detroit.
Naturally, the mainstream media focused on Detroit's leading-edge efforts in hybrid, electric, alternative-fuel, and high-mileage vehicles. But the same green technologies that have boosted efficiency and reduced emissions have spun off an additional benefit just for us: lots of horsepower. While only a few years ago, 500 hp in a production vehicle was unthinkable, thanks to all these advances, that number has become the new baseline. Suddenly, a manufacturer is not a serious player in the Motown horsepower wars unless it has a 500hp engine in its lineup. And now, Detroit has raised the bar again, this time all the way up to 600 hp in a single jump.
Chrysler
Dodge is the first to blow past the 500hp benchmark and officially raise the ante to 600 hp with its new Viper. Formally launched at the Detroit show as an '08 model, the new-and-improved snake goes on sale this summer. The Viper's old truck-based V-10 engine has evolved a bunch since it was introduced in 1992 and even since the previous (third-gen) version was revamped for 2003-the one rated at 500 hp. "It's the same architecture but almost every part has been touched," says SRT Engine Team Supervisor Kraig Courtney, whose group developed the powerplant with engineering input from Ricardo and McLaren Performance Technologies. The displacement is now up to 8.4 liters due to a 1.0mm bore increase, but that's mainly so the V-10 can share the forged pistons and cracked connecting rods of the 6.1 Hemi V-8. The real keys to the big power boost are in the cylinder heads and valvetrain. "We've used the classic racing-engine strategy: make more power with airflow and rpm," Courtney says.
The new cast-aluminum cylinder heads sport CNC-cut combustion chambers, and the valve angle has been reduced from 18 to 12 degrees. Intake-port cross-sectional area has been increased 13 percent for 23 percent greater airflow, while the exhaust ports are up 13 and 10 percent, respectively. A freer-flowing intake manifold uses a pair of 74mm throttle bodies (borrowed from the 4.7L V-8) with fly-by-wire control. There is a revised airbox, a new Motorola CPU that is 10 times faster with 100 times the processing power, and the redesigned roller lifters have been lightened 28 grams each. But easily the trickiest and most intriguing piece in this new engine is the camshaft.
Any rodder who has degreed a camshaft is familiar with lobe separation angle (LSA). A defining factor in engine performance, LSA is the angle between the intake and exhaust lobe centerlines, and on a single-cam engine, it is locked in when the camshaft is manufactured. A wide LSA is generally good for low-end torque, driveability, and emissions, while a narrow LSA means increased overlap and usually better top-end power. When you select a camshaft, you unfortunately have to pick one or the other or settle for a compromise somewhere in the middle-until now, that is. No such compromises are required in the Viper V-10, which uses a novel form of variable valve timing (VVT) Chrysler calls CamInCam.
Conceived by Mechadyne International in Great Britain and developed and manufactured by Mahle, the Viper camshaft can change its LSA on the fly.Actually, the piece is a camshaft within a camshaft, made up of two concentric elements (hence the name CamInCam). The exhaust lobes are fixed upon the outer element, while the inner camshaft carries the intake lobes. As commanded by the engine's ECU, a hydraulic actuator built into the cam sprocket alters the lobe separation angle between the intake and exhaust lobes up to 40 crankshaft degrees, while a sensor at the rear of the camshaft keeps track of it all.
For the Viper's engine calibration, the intake-lobe centerline is fixed at 118 degrees, while the exhaust-lobe centerline varies continuously from 108 to 140 degrees according to speed and load. (So LSA ranges from 113 to 129 camshaft degrees.) But in this case, more low-end torque was not the goal. "That has never really been a problem with the Viper," Courtney says with a smirk. Here, the strategy was to improve low-speed smoothness and emissions without sacrificing top-end breathing. While the long-stroke, odd-firing V-10 has never lacked for torque, it has never been much of a revver. The original 1992 version ran out of wind at only 5,400 rpm. Thanks in part to the CamInCam system, the new Viper redlines at 6,400 rpm and is rated at 600 hp at 6,100 rpm. And from what we hear, the horsepower number is conservative.
'08 Dodge Viper Specifications
Wheelbase: 98.8 inches
Length: 175.6 inches
Height: 47.6 inches
Front track: 61.6 inches
Rear track: 60.9 inches
Powertrain: 8.4L V-10 rated at 600 hp, six-speed manual transmission
Front suspension: Double wishbone independent, cast-aluminum control arms
Rear suspension: Independent, cast-aluminum control arms
Brakes: Four-wheel disc, 14-inch rotors, Brembo calipers
Wheels: Forged aluminum, 18-inch front, 19-inch rear
Tires: P275/35 ZR 18 front, P345/30 ZR19 rear
Curb weight: 3,450 pounds
General Motors
Once Chrysler threw down with its 600hp Viper, GM Vice Chairman Bob Lutz made it known that Chevrolet already has hardware in the pipe to answer the challenge. "As you all know, it is not our policy to discuss future product programs," Lutz said at the Detroit show. "However, it is very important for Corvette to be the most powerful, most capable, best handling sports car in the United States." Lutz acknowledged that "a recent competitor" had trumped the Corvette Z06's 505 hp. "But the Corvette vehicle-line executive will not take that lying down," he asserted. Very well, then.
The car to which Lutz coyly refers-the "Blue Devil" or "SS" or "LS9" Corvette as it is variously known-might be one of Detroit's best kept/worst kept secrets in years. While GM's communications people refuse to confirm or deny the car's existence, everyone in town seems to know about a new Corvette model due to appear in 2009. The hyper-Vette is shrouded in so many rumors and stories (and at least one hilarious hoax) that the absolute truth is impossible to pin down. But since HOT ROD loves motor gossip as much as anyone, here's what we think we know about it.
The new Corvette mill will actually be smaller in displacement than the Z06's LS7, Chevy's current top engine option. Instead of 7.0 liters, the new engine will displace 6.2 liters. The cylinder bores are smaller to provide greater block rigidity, which will be needed, as they are bolting up a blower to the Gen IV V-8. That's right, here comes the first supercharged production Corvette in Chevrolet history (reportedly). The blower system is said to be similar in layout and configuration to that used in the Northstar V-8 that powers the Cadillac STS-V: a beltdriven Roots blower and air/water intercooler are neatly enclosed in a compact module on top of the engine. It's an elegant setup that in the Caddy is good for a very refined 469 hp and 439 lb-ft of torque from only 4.4 liters. Word on the street is that with 6.2 liters to work with, the new Corvette will be making 650 hairy horsepower and 600 lb-ft of torque. Allegedly, Active Fuel Management (GM's version of displacement-on-demand) will be incorporated into the supercharged V-8, but not variable valve timing. We'll see.
The most popular car with the civilians at Cobo Hall this year was far and away the new Camaro convertible. The Detroit News awarded the Hugger Orange ragtop its Readers' Choice honor in a landslide. Both Camaro prototypes in public circulation-the silver coupe that did the HOT ROD Power Tour(r) last year and the convertible as well-are powered by LS2 V-8s rated at 400 hp. However, GM insiders have blabbed to HOT ROD the range of potential powertrain options for the new Chevy ponycar. There will be two V-6 choices and at least three V-8s, including a 550hp version of the supercharged 6.2L V-8 for a high-content Z28 model. Sources indicate there will be two base V-8s, one stick and one automatic, both of them over 400 hp.
'09 Chevrolet Camaro Specifications
Wheelbase: 110.5 inches
Length: 186.2 inches
Height: 53 inches
Front track: 63.8 inches
Rear track: 63.3 inches
Powertrain: V-6 and LS2 V-8 options with six-speed manual and automatic transmissions
Front suspension: McPherson struts with double wishbones
Rear suspension: Multilink independent
Brakes: Four-wheel disc, 14-inch rotors, with four-piston calipers
Wheels: Cast aluminum, 21-inch front and 22-inch rear
Tires: 275/30R21 front, 305/30R22 rear
Curb weight: 3,750 pounds (estimated)
Ford
Now that the '07 Shelby GT500 has officially been rated at 500 hp, Ford has a player in the Detroit muscle game at what has now become the Division II level. It remains to be seen just how and when Ford intends to step up to the new 600hp standard, though there are clues in the concept vehicles it placed on the floor at Cobo Hall in Detroit. The Giugiaro Mustang, previously unveiled at the Los Angeles Auto Show, uses a 4.6L Modular V-8 with a Ford Racing supercharger and intercooler. With 11 psi of boost, the three-valve engine has been rated at 500 hp.
The Ford Interceptor concept car is a "four-door coupe" aimed squarely at the Chrysler 300 and other rear-drive sports sedans, including BMW. Based on a stretched version of the Mustang S197/D2C platform, the Interceptor is equipped with a six-speed manual gearbox and a 5.0L Ford Cammer V-8, the same basic package found in the Mustang FR500C Grand Am Cup racer. Here the engine gets a revised induction system and recalibration to run on E85 fuel. It is rated at 400 hp. While it seems as though Ford may be lagging behind in the current horsepower wars, it could be the company is just looking a bit farther down the road.
At the Detroit show, Ford unveiled the Lincoln MKR concept vehicle, another four-door sports-luxury sedan, and like the Interceptor, it is based on a stretched Mustang chassis. While the styling and interior drew praise from the Cobo Hall crowd, what is special about the MKR is its engine. Ford calls the approach TwinForce: small displacement and high efficiency for low emissions and fuel consumption and tandem turbochargers and intercooling for big horsepower on demand. While the concept is hardly new, Ford is relying on some new technology to make it truly viable this time around.
The MKR's TwinForce engine is based on the new 3.5L Duratec V-6 used in the Ford Edge, turned from east/west to north/south orientation. Two small, intercooled turbos boost output from 265 to 415 hp, while direct fuel injection permits Ford to maintain the Duratec's original 10.3:1 compression ratio even at relatively high boost levels. Known in the industry as GDI (gasoline direct injection) or SIDI (spark-ignition direct injection), this system delivers fuel straight into the combustion chambers, which allows far more precise metering and controls peak combustion temperatures.
And as GDI/SIDI is developed, the industry is betting this technology will inevitably lead to another important breakthrough: HCCI, or homogeneous charge compression ignition. Imagine a high-speed, high-efficiency gasoline engine with no throttle or ignition system, combustion and output controlled entirely at the injectors, and with the fuel economy of a diesel and the performance and emissions of a gasoline engine. Insiders say this technology could be on the road in the next five to ten years. Back to the immediate future: All three domestic manufacturers have direct-injection systems in production or development for their smaller engines, and it won't be long before that technology is applied to the big V-8s and we see another huge leap in performance. Seven-hundred horsepower, anyone?
'07 Ford Shelby GT500 specifications
Wheelbase: 107.1 inches
Length: 188.0 inches
Height: 54.5 inches
Front track: 61.9 inches
Rear track: 62.5 inches
Powertrain: 5.4L supercharged V-8, six-speed manual transmission
Front suspension: McPherson struts, independent
Rear suspension: Live axle, three-link with coil springs
Brakes: 14-inch rotors with Brembo four-piston calipers front, 11.8-inch rotors with two-piston calipers rear
Wheels: 18-inch cast aluminum
Tires: P255/45R18 front, P285/40ZR18 rear
Curb weight: 3,920 pounds
Ford Interceptor Concept SpecificationsWheelbase: 120.8 inches
Length: 201.6 inches
Height: 54.8 inches
Front track: 66.5 inches
Rear track: 67.8 inches
Powertrain: 5.0L Cammer V-8, E85 fuel, 400 hp, six-speed manual transmission
Front suspension: Double wishbone independent
Rear suspension: Independent, three-link
Brakes: NA
Wheels: 22-inch forged aluminum
Tires: NA
Curb weight: 4,250 pounds (estimated)
Lincoln MKR specifications
Wheelbase: 112.9 inches
Length: 195.7 inches
Height: 52.7 inches
Front track: 63.7 inches
Rear track: 63.8 inches
Powertrain: 415 hp, 3.5L twin-turbocharged V-6, six-speed transmission
Front suspension: Independent, double wishbone
Rear suspension: Independent, multilink
Brakes: N/A
Wheels: N/A
Tires: N/A
Curb weight: 4,075 pounds

Photo Gallery: Motown Muscle - Hot Rod Magazine



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