Tom Wilson
August 1, 2009
Photos By: Courtesy Of Edelbrock
Seen during installation without its decorative coil-cover side panels, the E-Force supercharger still stands out as a handsome addition to the top of an S197 Mustang engine compartment.

Although we've been there many times, we always get a bit of automotive acrophobia when taking in Edelbrock's main facilities in Torrance, California. Besides the unparalleled history of the place--Vic Edelbrock Sr. started the company in 1938--the scale of the business sets us back. Most automotive performance aftermarket companies are some version of cottage industry, but Edelbrock is high-performance on an industrial scale.

Such a feeling is difficult to ignore when walking among rows of busy CNC machines, going from room to room holding manufacturing, shipping, warehousing, marketing, and corporate offices, or ogling the latest in rapid prototyping capabilities. And then you realize this is just one of three Edelbrock campuses in Torrance; there are two additional foundries, one for sand molds and another for permanent molds, in San Jacinto, California.

So it's with an understanding that Edelbrock doesn't just off-handedly toss parts into the aftermarket that we went to inspect Edelbrock's E-Force supercharger at close range. We had seen the new blower at the SEMA show, but this was an in-depth visit to study, install, and dyno the new blower for '05-'09 Mustang GTs--and '10 GTs after Edelbrock gets a chance to verify the fit.

Here's how the E-Force comes out of its shipping box, except that the fuel injectors and rail have been added for a little highlight. There's no need to fiddle with any difficult or sensitive blower assembly work because it's done at the Edelbrock factory.

What we found is a supercharger aimed squarely at the center of the street market with a performance reserve for track-oriented cars as well. Edelbrock's design philosophy with this supercharger is to provide a fully engineered product the average enthusiast can bolt onto his real-world street S197 Mustang and have some fun. There is a higher-output competition version of the E-Force, but the emphasis is not on trailered, rollcaged race cars.

A quick review of Edelbrock's in-house testing shows the E-Force makes over 400 rwhp on the company's SuperFlow chassis dyno in the 6 to 8 psi range, which jibes with the 466 flywheel horsepower shown in the ads. Combined with the 439 lb-ft of torque at the rear tires, that's a definite bump in the backside. We also saw a touch over 600 flywheel horsepower (up to 650 now) on Edelbrock's built, free-breathing Three-Valve dyno mule, so there's power to be had here.

Recognizing it would be impossible to better a dedicated specialist when it comes to the heart of supercharger design, Edelbrock teamed with Eaton Corporation for the fundamental guts of its new supercharger, the rotor set; Edelbrock builds the remainder of the supercharger.

Edelbrock's E-Force layout is distinctly two-story. Downstairs is the supercharger itself, along with the air inlet, drive snout, and bypass valve. Upstairs is populated by the charge-cooler core and the intake runners. By arcing from the far side of the manifold, over the top of the charge cooler, and then down into the ports, the intake runners are long for good off-boost torque.

Eaton is a large OEM-level supplier, and we've all seen its superchargers before on Thunderbird Super Coupes and the '03-'04 Mustang Cobras, along with numerous Aston Martin, Mercedes and others. For the Edelbrock E-Force supercharger, the latest TVS rotor set was chosen. This is the same rotor set used in the ZR-1 Corvette. It's a four-lobe, 160-degree twist design displacing 2.3 liters of air per revolution. Eaton uses Twin Vortices Series--TVS--to denote this highly twisted rotor design.

There has been much discussion comparing the merits of the twisted-Roots design of the TVS blower versus the male-female arrangement of twin-screw compressors, and frankly, we don't intend to settle that argument here. Both are advanced designs, and at anything approaching normal boost pressures, the differences between these designs is likely academic. By the time one supercharger shows superiority to the other, it's likely time to bolt on turbochargers anyway, so we'll leave it at that.

One place where the TVS has an edge is price. Edelbrock is able to sell its Mustang supercharger for $5,795.99. This is notably less than the newest twin-screws on the market, but how much of the price delta is attributable to the price of TVS rotors or simply Edlebrock's economy of scale is impossible to determine.