Next was completing the discharge side of the kit. This section of plumbing was critical for optimal performance. If the discharge was too restrictive, turbulence and heat would be created, causing boost distortion. The supercharger discharge flange was designed using the latest in computer-aided technology, resulting in a part that maximized air flow capacity and lowered discharge temperatures. The rest of the plumbing from the flange to the intake manifold was mandrel bent to ensure concentric bends and maximum air flow. Proper working conditions were ensured through the installation of an air bypass valve system (aka diverter valve) to maintain proper boost control. The system is vacuum operated and determines when boost should be retained or released. Since the supercharger requires high pressure oil feed, Bahn Brenner installed an oil feed line and an oil drain line.
Last, but certainly not least, was the issue of fueling and software. If the vehicle has OBD-I, the supercharger kit will include a larger fuel pressure regulator system, a kit to reroute the idle stabilization system and corresponding software. If the vehicle is equipped with OBD-II, the supercharger kit comes with a set of four larger fuel injectors and corresponding software. The culmination of Bahn Brenner's design elements resulted in a stage-one supercharger kit that increases power output by 60%, which equates to approximately 177 bhp and 180 lb-ft of torque.
If after you complete the stage-one upgrade you're still left wanting more, Bahn Brenner offers two additional stages. The stage-two upgrade consists of a custom Bahn Brenner head gasket to lower the compression, a higher lift camshaft, smaller supercharger pulley to increase the boost pressure and a new ECU program. All these parts are said to net an additional 20 whp.
The stage-three upgrade is designed to combat the extra heat generated by the increase in boost pressure. This kit consists of a new intake manifold with a built-in air-to-liquid intercooler, electric water pump, reservoir tank, Setrab heat exchanger, hoses and fittings. Also included in the kit is a stage-three-specific smaller pulley to push boost even higher and new ECU software to complete the package.
Blower 411There are three main types of supercharger designs currently being used in the automotive industry: centrifugal, Roots and screw.
CentrifugalCentrifugal superchargers are basically belt-driven turbochargers. As air is drawn into the snail-shaped compressor housing, the velocity is increased by a high-speed impeller (the high speeds are produced by internally overdriving the input shaft, which is also overdriven by the external drive pulley) and forced out through the scroll of the supercharger.
RootsThe Roots-type supercharger is classified as a positive displacement system. A Roots-type supercharger does not actually compress air, it just moves it very quickly. As air is drawn into the supercharger inlet it collects in the areas between a pair of counter-rotating rotors moving it within the housing and forcing it into the intake manifold at a high velocity.
ScrewThe screw-type supercharger is the latest development of the Roots-type supercharger, the main difference being the way boost is produced. As air is drawn through the inlet it is compressed internally between the rotors. The male rotor rotates clockwise while the female rotor rotates counterclockwise, compressing the air between the rotors and forcing out the discharge.