LS7 Engine To Live On In New Camaro Z/28
GM announced yesterday that the 2014 Camaro Z/28 will be powered by the LS7, promising a powerplant that will be rated at least 500 horsepower with 470 lb-ft of peak torque. The LS7 in the sixth-generation Corvette Z06 is rated at 505 horsepower with a similar torque rating. Redline is 7,100 rpm.
“The LS7 lives on in the all-new Z/28, extending a performance legacy while delivering great power density in a lightweight package,” says John Rydzewski, assistant chief engineer for small-block engines.
The 7.0-liter LS7, of course, is known for bringing exotic materials and a host of racing technology to the street, and it’s GM’s most powerful naturally aspirated engine. It will be positioned between the 426-horsepower LS3 in the Camaro SS and the supercharged LSA engine in the Camaro ZL1 — both at 6.2 liters.
The LS7 shares the basic architecture of the LS3 but features a unique cylinder block castng with press-in steel liners to allow 104.8mm bores. The forged-steel crank comes with a 101.6mm stroke, giving the LS7 is 7.0-liter or 427ci displacement. Compression ratio is 11.0:1.
Handbuilt at GM’s Performance Build Center in Wixom, Michigan, the LS7 features titanium connecting rods and 56mm intake valves. The rods weigh just 464 grams each, which is 30 percent lighter than the LS3 rods. Other LS7 components include flat-top pistons, tri-Y exhaust manifolds and a high-lift hydraulic roller camshaft. The 12-degree cylinder heads feature CNC-machined rectangular intake ports, 70cc combustion chambers and sodium-filled 41mm exhaust valves. The new Camaro Z/28 will come with dry-sump oiling that boasts a 10.5-quart reservoir.
By way of a history lesson, the original Camaro Z/28 engine was a 302ci (4.9-liter) small-block rated at 290 horsepower and 290 lb-ft of torque. Chevy built the engine to compete in Trans Am racing by mating the 327ci block and its 4.0-inch bore and the 283ci engine’s 3.0-inch-stroke crankshaft.
The LS7, with its all-aluminum construction and composite intake manifold, actually weighs 20 percent less than the original 302 engine, yet packs 73 percent more horsepower.