Domestic and exotic: The former refers to homegrown fare, but also implies the docility of a family pet. The exotic suggests foreign origins, along with alluring connotations of things that are strikingly and excitingly out of the ordinary. But you know what? GM's spectacular new LS9, the 638hp heart of the upcoming ZR1 Corvette supercar, is a stunning amalgam of both. It's certainly domestic-though you can throw out that whole docile thing-built with an exact mix of handbuilt attention and technological precision at GM's Performance Build Center in Wixom, Michigan. And as for exotica, calling this engine striking and exciting hardly does the thing justice. It is, after all, simply the most powerful production engine GM has ever created. This is our ultimate inside look at this impressive creation: We explored its conception and design and even participated in the meticulous assembly process for one of the very first examples.
In talking about how the LS9 came to be, it's important to remember that nothing happens in a vacuum. It's impossible to separate the development of the ZR1 from the development of the tremendously powerful engine under its hood. In fact, talk of the LS9 started hard on the heels of the introduction of the LS7, then the pinnacle of GM small-block development. What, 505 hp in the hot-handling Z06 wasn't enough? It never is, as Dean Guard, small-block chief engineer and program manager, pointed out. "You don't have to be a fan of Corvette to know more is always better," he observed. "Corvette customers always demand progress, so there's always something on the drawing board."
In this case, what was cooking on the engineers' slates was the "Blue Devil," a prototype vehicle that embodied GM's desire to build an ultra-Corvette that was every bit the equal of Europe's wildest supercars. The key to making it happen was the synergy between the Corvette team and the powertrain team. The challenge to the Corvette team was to make a definitive automotive statement. And for Guard and his colleagues, "Frankly, the challenge to the powertrain team was to deliver ultimate performance." But it couldn't have happened without the ZR1 Corvette. Said Guard: "After all, you can't do something like this and put it on a shelf, right?"
So, on to the heart of the matter: the 638hp, 604-lb-ft LS9. For convenience's sake we'll start at the top, with the prominently displayed Eaton R2300 supercharger running at 10.5 psi of boost through a liquid-to-air intercooler setup. Why a supercharger, we asked? "With the LS7 at 505 hp, that's about all there is," Guard confessed. "With drivability and non-trivial emissions and diagnostic concerns, we had to enter the charged arena." And though Corvette has a turbocharged history with the Callaway Corvettes of yore, it wasn't to be this time. "Supercharging is preferable to turbocharging," Guard explained. "There's better packaging, and it better handles the thermal and emissions challenges." Then there's the availability of the sixth-generation supercharging technology from Eaton. Guard called it simply "the best charging tech available."
Besides the fact that the typical supercharger whine is nonexistent, the powerband is tremendous. GM Powertrain's numbers show the engine as making 320 lb-ft of torque-at only 1,000 rpm. The peak of 604 lb-ft happens at about 4,000 rpm. Most impressively, according to GM, the LS9 is producing 90 percent of peak torque from 2,600 to 6,000. Can you say massive acceleration, anytime? According to Ron Meegan, assistant chief engineer, "The sixth-generation design of the supercharger expands the 'sweet zone' of the compressor's effectiveness, broadening it to help make power lower in the rpm band." This is, of course, done without sacrificing the tremendous high-rpm power the LS9 produces.
What We Did
Got the real story behind GM's most potent engine ever, and helped build one of the first production examples
638 hp and 604 lb-ft backed by a five-year, 100,000-mile warranty
$103,300 for a LS9-powered ZR1 Corvette