Forced Induction (Supercharger)

The Supercharged Engine
Boost - Charge - Power

Superchargers are the most cost-effective way to increase engine power, adding an average of 46% horsepower and 31% more torque. Easy installation and maintenance make superchargers the most cost-effective way to increase performance power. Add excitement to your driving experience…

What is a Supercharger?
A supercharger is a pump used to force more air into the combustion chamber of an engine. It draws air in, squeezes the air into a smaller space and discharges it into the intake manifold. It is combined with fuel to form an explosion (charge) that is ignited by the spark plug. The force of the charge drives the piston down creating motion that is eventually transferred to the wheels. Superchargers spin at speeds as high as 50,000 to 65,000 rotations per minute. A supercharged engine can be powered mechanically by belt, gear, or chain-drive from the engine's crankshaft. Superchargers can also be driven by a gas turbine. A turbine-driven supercharger is powered by pressure of exhaust gases forcing air into the engine.

Why use Superchargers in High Altitudes?
Engine performance deteriorates in high-altitudes due to air’s low density. Internal combustion engines of airplanes use superchargers due to high altitudes because they deliver higher-pressure air to engines for optimal operating. The boost from a supercharger places about 50 percent more air into the engine.

Why use Positive Displacement Superchargers?
A positive displacement pump delivers a constant level of boost, dividing air into parcels, mechanically moving air into engine bit by bit. They absorb as much as a third of crankshaft power Positive displacement pumps use either external or internal compression.

Why Use Dynamic Compressor Superchargers?
Dynamic Compressor Superchargers deliver increasing boost with increasing engine speed. They rely on accelerating the air to high speed and exchanging that velocity for pressure by slowing it down. Comprex superchargers do not fit neatly into either dynamic or positive displacement categories; they use the exhaust gas to directly compress the incoming charge.

About Compressed Air…
Keeping the air that enters the engine cool is an important part of the design of both superchargers and turbochargers. an intercooler between the pump and the engine to reduce the temperature of the air. As compressed air increases in temperature it expands less and loses density causing less power when ignited by the spark plug. Superchargers cool compressed air before it enters the intake manifold. The “intercooler” is a small radiator responsible for this cooling process. Intercoolers come in two basic designs: air-to-air intercoolers and air-to-water intercoolers. Cooler air or water is sent through a system of pipes or tubes. As the hot air exiting the supercharger encounters the cooler pipes, it also cools down. The reduction in air temperature increases the density of the air, which makes for a denser charge entering the combustion chamber.

About Internal Compression…
Internal compression air is compressed within the supercharger, delivered to engine with little backflow. This is more efficient than backflow compression and allows higher efficiency to be achieved. Internal compression devices usually use a fixed internal compression ratio. When the boost pressure is equal to the compression pressure of the supercharger, the backflow is zero. If the boost pressure exceeds that compression pressure, backflow can still occur as in a roots blower. Internal compression blowers must be matched to the expected boost pressure in order to achieve the higher efficiency

About External Compression…
External compression transfers air at ambient pressure into engine. If the engine is running under boost conditions, the pressure in the intake manifold is higher than that coming from the supercharger. That causes a back flow from the engine into the supercharger until the two reach equilibrium. It is the back flow that actually compresses the incoming gas. This is a highly inefficient process and the main factor in the lack of efficiency of roots superchargers when used at high boost levels. The lower the boost level the smaller is this loss and roots blowers are very efficient at moving air at low pressure differentials, which is what they were first invented for Roots and Twin-Screw Superchargers provide more power at lower RPM. Centrifugal Superchargers provide more power at higher RPM

What are the Advantages of Supercharging?

  • An inexpensive way to increase horsepower.
  • Power increases of 50 to 100 percent with no “lag”
  • Better gas mileage than engines of equal power
  • Bolted to top or side of engine for easier access

    Supercharged Engine Requirements…
  • A Strong Engine & Transmission
  • Heavy-Duty Components
  • High-Octane Premium Gas

    Supercharged Engine Effects…
  • Drivetrain Warranty - may be voided
  • Life Expectancy of Engine - may be reduced
  • Additional Torque - may be a problem
  • Undersize Components - creates excessive heat


Boost: Boost is the ratio of revolutions before and with air compression by a blower

Charge: a charge is a packet of potential energy that can be turned into useful kinetic energy through a chemical reaction known as combustion.

Lag: Lag refers to the time it takes an engine to respond when a gas pedal is depressed