Started by Jim Bell in 1968, who initially specialized in Buick engines, super tuning and later turbo charging, Kenne Bell pioneered the concept of a twin-screw, positive-displacement supercharger for fuel-injected engines in 1991. These units feature dual rotors mounted inside a case that bolts on top of the engine's intake manifold. The twin-screws developed a reputation for their quiet operation and instant boost at low rpm. The rotor design, in comparison with other Roots-type blowers, promoted greater efficiency with lower parasitic loss-hence more power could be made via lower levels of boost. In For circles, the popularity of Kenne Bell systems really took off with the introduction of the '03 Mustang Cobra. Although powerful, even with the factory-installed Eaton/Roots blower, owners discovered that by changing to a Kenne Bell, over 600 hp at the rear wheels was possible using an otherwise essentially stock engine (up from 370 hp at the tires with the factory setup). Since then, Kenne Bell has expanded its supercharger offerings for F-150 Lightning pickups with the 5.4L Triton V-8, as well as kits for the Mustang 4.6 Two-Valve V-8s, both the '96-'98 versions, and the performance-improved '99-'04 variety.
Today all Kenne Bell superchargers have been upgraded in capacity and the 2.1L kit is the company's most popular item. It's designed to bolt on a stock lower fuel-injected intake manifold or Ford Racing GT40. It delivers a 60-80-degree reduction in air temperature and is designed to deliver a steady amount of boost, from idle all the way up to redline. The standard kit is designed to run at 6-9 psi and is fully 50-state emissions legal. An optional bypass valve is available for higher boost applications and is designed to reduce the risk of a detonation, often caused by excess buildup of compressed air at the throttle body. These kits are available for '86-'93 and '94-'95 Mustang 5.0 V-8s; '96-'98 and '99-'04 Mustang GT Single Overhead Cam 4.6 V-8s; and the 4.6L Dual Cam Cobra V-8s ('96-'98 and '99-'01, '03-'04 Mach 1).
If you're looking for more power, Kenne Bell offers its Blowzilla 2.2L kit, which incorporates larger rotors, pushing the power envelope further. It's designed to work on more highly modified engines, including 4.6s and 5.4s, as well as strokers such as the pushrod 331, 347, and 408 Windsor V-8s, plus 5.0L cammers. Because the supplied Standard inlet tube starts posing a restriction on airflow, K-B offers its larger Flowzilla inlet and bypass, which requires an 80mm mass air meter and 70mm throttle body to work effectively. The Blowzilla kit is designed to deliver up to 785 hp, though beyond 700 hp K-B recommends upgrading your Mustang or Ford's stock fuel system, including recalibrated Mono Chip fuel injectors, Boost-A-Pump, fuel rails, and pump.
If the Blowzilla isn't enough, you can always step up to the 2.6L Big Bore kit. Bear in mind, this is designed for more hard-core, all-out performance applications. Still, it is designed to cover a wide range of different boost applications, anywhere from 9 to 26 psi, though it does need to be used in conjunction with a 4.6 engine that has built internals as well as forged pistons and connecting rods. Due to its height, the 2.6L also won't clear the stock hood on your Mustang and will require a Cobra R-style design to fit. Kenne Bell also markets a 2.6L kit designed specifically for second-generation Ford F-150 Lightning and Harley Davidson pickups.
2.6L '03-'04 Cobra Kit
Because the '03-'04 Cobra engines came with Eaton superchargers from the factory, they already received stronger cast-iron blocks, forged crankshafts, H-beam rods, and forged pistons. Consequently, they're better able to withstand higher levels of horsepower and boost than the naturally aspirated '96-'04 units. As a result, Kenne Bell's entry-level kit for these cars is a 2.6L unit. It boasts a 30 percent lower intake charge temperature than other twin-screw blowers and is designed to use the Cobra's stock crank pulley and fit under the factory hood. Dyno tests have shown that the 2.6L Cobra kit can provide power gains of 289 hp versus the factory Eaton blower on an otherwise essentially stock engine.
2.6L '05-'08 Mustang GT
One of K-B's newest kits is the 2.6L twin-screw supercharger for the '05-'08 Mustang. These are available in Stage 1 and Stage 2 packages for up to 10 pounds of boost.
For the hard-core power junkie, K-B has brought out its line of Mammoth Superchargers. Mammoth actually refers to the inlet tract, designed to accommodate massive 75mm dual throttle bodies, maximizing flow through to the big-bore twin-screw rotors and massive case, though the Mammoth will still work with stock-sized 60mm units. Over years of testing, Kenne Bell discovered that the inlet tract is the area responsible for the biggest losses in airflow on many twin-rotor supercharger systems, which is why the Mammoth was developed. Mammoth 2.8L blowers are available for '03-'04 Cobras, '07-'09 Shelby GT500s, and shortly, '05-'06 Ford GT Supercars.