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Kenne Bell Twin Screw Supercharger - Bell Curve - 3.6-Liter Twin Screw
Kenne Bell Raises Its Grade To 1,100 Horsepower With A 3.6-Liter Supercharger
Architecturally, the cooling water could be part of a self-contained system, shared with the engine cooling water or borrowed from the charge cooling ("intercooling") water-to-air system. Kenne Bell elected for the latter, tapping into the charge-cooling system. This keeps piping and hoses to a minimum and doesn't require yet another heat exchanger in front of the radiator. The charge cooling water runs coolly, too, so it gives the blower maximum chill.
Another change is the use of larger bearings and straight-cut rotor gears. The larger, heavier rotors require the larger bearings, and also drive the need for straight-cut rather than the helical gears found in other Kenne Bell superchargers. The new drive gears are housed in a new billet front bearing bulkhead; not the old cast bulkhead of the 2.8-liter.
The gear issue comes during deceleration. Helical gears induce a thrust or twist on one rotor, and with the 3.6's heavier rotors this effect is sufficient to drive the rotors out of time, more quickly crashing them together when they get hot. Straight-cut gears don't induce the thrust and migrating rotor timing is thus not an issue. Furthermore, the straight-cut rotor gears are even stronger, and, of course, they are noisier than helical gears. Jim Bell says the 3.6-liter is quieter than a straight-cut geared centrifugal, and we'll have to take his word on it as the only 3.6 we've heard to date was on the test engine outlined in this article, and it was running 1,000 hp worth of open exhaust in a cinder block enclosure. Rob Zombie could have been demon speeding in the data room when this super beast was bellowing and you wouldn't have heard him.
Yet another high-boost consideration of the 3.6 are its oil seals between the front bearings and the rotors. These seals can be caught in a real pressure differential between the ear-popping rotor cavity and atmospheric pressure in the drive chamber, so for the 3.6 Kenne Bell ported the drive chamber to equalize the pressure on the seals and hugely reduce the chance of their failure. This is called Seal Pressure Equalization in KB-speak.
Something Jim Bell would like us to remember is his newest blowers use his latest rotor profiles-the fine detailing of the rotor shapes-for maximum efficiency. Furthermore, he says his 4x6 rotor pack is inherently superior.
Jim Bell also reminded us that his 2.8 blower already requires notching the factory hood reinforcement structure for clearance; the bigger-yet 3.6 will demand about a 2-inch-rise aftermarket hood or lowering the engine. Interestingly, Jim says this is a deal-breaker for Corvette owners, but hardly a hiccup for the modification-mad Shelby GT500 crowd. "I already have a big hood!" is their response.
Thanks to the 3.6's size and appetite for air the inlet casting required enlargement, so it's actually a new, slightly larger casting detailed to smooth airflow into the 3.6. It's still called the Mammoth, however. Other than those changes the 3.6 blower is a 2.8 kit with the larger supercharger.
Clearly the new 3.6-liter Kenne Bell supercharger is a superior belt-driven mouse trap when it comes to making massive power on GT500s. If mega-power is your thing, the 3.6 seems a great way of getting it.
Of course, hooking this sort of power to the pavement without breaking anything is between you and your chassis builder; or your right foot where you learn to lead a sensitive life and consider tire-spin a cheap fuse for driveline breakage.
Pricing for the 3.6 blower is $6,899, well ahead of the 2.8H option, which remains available as the best GT500 choice for 16 pounds or less (pump gas) applications. More details on the 3.6's construction and dyno test are in the photos and captions; here's to big boost!