Even though bolting on a blower is one of the most cost-effective ways to achieve power gains on your Corvette, nobody ever said superchargers come cheap. Not only that, but other hidden costs can crop up during installation and tuning. And there's one more big expense that might need to be factored in: replacing the factory hood with a taller, aftermarket piece that clears the blower case. (And that doesn't include prep and paint, which can really add up if you need to match your Vette's custom hues.)
All of which leads us to Edelbrock's new E-Force Supercharger for '08 to '10, LS3-powered Corvettes. How so?
"One of our primary requirements was to have it fit under the hood-but with no sacrifice in performance," notes Robert Simons, the company's vice president of research and development. After all, why force a customer to spend at least a couple grand above and beyond the price of the puffer, just to get it to fit?
Of course, there's a lot more to the unit than the packaging. Edelbrock prides itself on attention to details and innovations in design that not only improve performance, but also simplify installation. After driving Vic Edelbrock Jr.'s supercharged C6, we spent a significant amount of time going through the layout of the E-Force system with Simons. We came away with a renewed respect for how much effort the company expends to ensure that its parts both fit and perform as claimed. In this case, the resulting engine output comes pretty close to a ZR1, but at a fraction of the price.
Getting the E-Force to fit...
Getting the E-Force to fit under a stock C6 hood was a design priority for Edelbrock. A matte-black blower case and coil covers yield an understated look reminiscent of an AMG Mercedes.
Cutting to the juicy part, the power levels that can be reached are impressive, hitting as high as 599 hp and 547 lb-ft of torque at the flywheel in the 7.5-psi Street kit (PN 1591), which comes with a high-flow fuel pump and a 3.50-inch blower pulley. That's a gain of 164 horses, or a 37.7 percent increase in output!
If you prefer not to swap out the factory fuel pump that's embedded in the tank, you can still achieve 554 horses and 515 lb-ft of torque with the 5.5-psi Street kit (PN 1590). You can always upgrade to the higher-output version later on if desired, but note that the E-Force is not currently compatible with Z06 or ZR1 models. It will fit on a '10 Grand Sport, though.
Since the LS3 has a higher compression ratio than the LS9 (10.7:1 versus 9.1:1) and no forged internals, the boost can't go as high as the 10-psi level seen on the ZR1. However, a Competition version of the E-Force is available as well, using a pulley as small as 2.75 inches in diameter. Power output will depend on the engine combo in question, with boost levels ranging from 7.5 to 18 pounds. This system is based on the 1590 Street supercharger but pared down to the bare essentials, leaving off extras typically customized by racers for a competitive advantage.
These power levels result from a combination of Eaton's new rotor design (also used on the ZR1) and Edelbrock's unique application and enhancement of the technology. As noted in a previous article, Eaton's axial-flow TVS (Twin Vortices Series) supercharger has dual four-lobe rotors with a 160-degree twist. The much higher helix angle, along with refinements to the port geometry, is designed to minimize pressure variations for a smoother discharge of air and higher efficiency over traditional Roots units.
Edelbrock optimizes the design even further in a variety of ways, from the blower-case configuration to the hose fittings on the intercooler. In contrast to other positive-displacement systems, the case was not only rotated so the inlet and drive pulley are at the front of engine, but also inverted so airflow goes upward. After exiting the case, the air goes through air/water intercoolers on the sides of the unit (rather than on top, like the ZR1). It then feeds into 12-inch runners underneath the case, which dump into the heads.
Like the Eaton TVS on which...
Like the Eaton TVS on which it's based, the E-Force uses dual four-lobe rotors with a 160-degree twist. The previous Eaton design employed a less efficient three-lobe/60-degree configuration.