97-03 F150, 97-02 Expedition Supercharger   Our truck and SUV kits are a direct bolt on to your 4.6 or 5.4 liter modular V8. The intake manifold ships complete and directly replaces the stock piece. Factory vacuum hoses and electrical connections are retained for a quick and clean install. All Allen supercharger systems are intercooled to reduce charge temperatures, and increase performance/ durability. This allows the stock programmed ignition timing to be used without worry of detonation. Premium fuel (91 octane or better) is required as with all our supercharger systems. To eliminate the pumping losses associated with idle or cruise conditions, a bypass valve is used. This allows an air path between the inlet and outlet of the blower during throttled conditions. Assive vacuum canister automatically closes the valve when inlet manifold pressure rises, and the blower makes boost instantly and seamlessly. They bypass valve makes the supercharger system virtually silent during non boost conditions. It also creases fuel efficiency over a non bypassed system. All truck kits produce about 5.5 psi boost pressure and upgrade kits are not available, or recommended. A 75 HP ncrease at the rear wheels can be expected on an otherwise stock vehicle. The extra 100 Ft-Lbs of low end torque is really what the trucks and SUV’s need to perform well!They bypass valve makes the supercharger system virtually silent during non boost conditions. It also creases fuel efficiency over a non bypassed system. All truck kits produce about 5.5 psi boost pressure and upgrade kits are not available, or recommended.A 75 HP ncrease at   the rear wheels can be expected on an otherwise stock vehicle.The extra 100 Ft-Lbs of low end torque is really what the trucks and SUV’s need to perform well!   1999 Ford F150 5.4L (at rear wheels)