General Motors’ Powertrain Group set out some tough goals when it laid out the fundamentals of the new Corvette ZR1’s engine. But rather than look at Vipers and GTs, engineers turned their attention toward Germany when designing the new LS9 engine.
The German competition is driving the higher horsepower and torque numbers coming to the Corvette, Chevrolet engineers told TheCarConnection.com at a recent backgrounder on the new supercar, slated for a debut at the Detroit auto show next week. The LS9 was specifically made to match up favorably with the V-10 engine found in the BMW M range, Chevy says.
The LS9 will produce 620 horsepower, or 100 horsepower per liter, and 595 pound-feet of torque, but that torque number should exceed 600 by the time GM's engineers finish tweaking the motor in mid-2008. The engine produces 90 percent of its peak torque from 2600 rpm to 6000 rpm.
The basic engine block is the standard one used for GM's other 6.2-liter V-8 engines. The LS9 tweaks the basics with forged aluminum pistons, polymer coatings, and titanium connecting rods. The inlet valves are also made from titanium, and iridium-tipped spark plugs and a specially designed dual pressure emission system are tailored to the engine. While some of the parts are carried over from the LS7, the camshaft, water pump and gaskets are all specifically designed for the higher output of the LS9.
The LS9 engine also will use a large positive-displacement supercharger developed specifically for the car by Eaton. The four-lobe supercharger is matched with an integrated charge cooling system that reduces inlet air temperature and maximizes the engine’s performance. The LS9 is only the first of several new supercharged small-block engines that will be introduced in GM vehicles in the future, including in large sport-utility vehicles and pickup trucks, Chevrolet engineers add.
GM didn't release any official fuel-economy numbers for the new engine, but engineers indicated that it should easily get in the high-20-mpg range in highway driving.--by Joseph Szczesny