2015 Chevrolet Corvette Z06 Deep Dive: What Makes the New Supercharged LT4 V-8 Tick?

September 3, 2014 at 3:14 pm by K.C. Colwell
Car and Driver Magazine

When engineers at General Motors say they have created one of the lightest and most compact 650-hp engines in production, our interest is piqued and we’re paying close attention. That’s especially true when that engine, a supercharged 6.2-liter LT4 V-8, is destined for the all-new 2015 Chevrolet Corvette Z06.

Although the switch from the previous Z06′s high-revving 7.0-liter LS7 to forced induction may have upset some purists, the beating heart of Chevy’s gnarliest car is also the most powerful production engine GM has ever built. And it keeps pretty exclusive company: The list of current production engines producing 650-plus horses is a short one: the recent Hellcat Hemi V-8 from Dodge, a trio of Ferrari V-12s (found in the F12berlinetta, the FF, and the LaFerrari), the Lamborghini Aventador’s V-12, the Bugatti Veyron’s insane W-16, and the McLaren P1’s twin-turbo V-8. (The plug-in-hybrid Porsche 918 Spyder misses the cut by virtue of its V-8 producing 608 horsepower on its own.)

In addition to output, GM’s small-block needn’t worry about its size. Pushrod V-8s, such as the new LT4 and the LT1 on which it is based, make the most of a single camshaft mounted low in the block. Dual-overhead-cam V-8s have four camshafts mounted high in the engine, making those powerplants—all else being equal—taller and wider overall, not to mention heavier. We love the sound of 32 valves banging and four cams spinning as much as anyone else, but there is an elegant simplicity to a 16-valve pushrod engine that can’t be ignored. It gets the job done.

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