Roots vs. Centrifugal vs. Screw Type Supercharging
The most effective performance enhancement that you will ever do to your car or truck is definitely a supercharger. That is why it is very important that you choose the right type of supercharger to get the right kind of power for the type of conditions that you will put your vehicle through. This is a guide to help understand it’s not just about forcing more air down the throat of your motor. There are different ways to get the air to the motor and these different ways create different type of power curves.
Centrifugal Type Supercharging
Centrifugal Supercharging compresses the air inside the case of the supercharger using an impeller. Then, discharges the air out of a scroll to the motor. This design is similar to turbo-charging except for centrifugal superchargers don’t use the exhaust to build pressure, they use a belt, driven by the crank pulley to spin the impeller. Centrifugal supercharging is definitely one of the more user-friendly ways to supercharge your motor. The ability to change the impeller sizes and to spin the impeller at different speeds creates a more inexpensive way to have flexibility in your power curve. Centrifugal superchargers have become the standard for street use and light-duty racing and far outsell all other types of superchargers.
Recommended Usage: Street Use – Commercial Use – Road Racing – Drag Racing
Positive Points: 1) Lots of Flexibility for Power Adjustments 2) Lower Discharge Temperatures 3) Great Reliability 4) Easy to install
Negative Points: 1) Not as much power at low RPMs as Roots or Screw type superchargers
Manufacturer Availability: Paxton – Powerdyne – ProCharger – Vortech
Vortech’s Centrifugal Type Supercharger
Roots Type Supercharging
The Roots Type Supercharger is the first style supercharger that was ever used and can be dated back to the 1880s when the Roots brothers designed it as an air conveyor for mine shafts. Roots blowers act like air pumps (not compressors), and In general, Roots blowers have a two or three lobe rotor design, depending on the size of the case. Roots blowers will give you positive pressure to your motor from just a crack of the throttle, and will give all that they have to offer at full throttle no matter what the rpm of the motor.
Roots Type Superchargers may look awesome hanging out of the hood and are great for those looking for drastic power increases at lower RPMs. Roots blowers are also extremely reliable and require very little maintenance, which is why Ford, GM, Mercedes, Jaguar, and Austin Martin have all featured Roots-style Eaton blowers as original equipment on select high performance vehicles.
Recommended Usage: Street Use – Towing – Extreme Drag Racing – Show Vehicles
Positive Points: 1) Boost throughout the entire RPM range, right off of idle 2) Highest Potential for Gain (A must-have for all-out drag racing) 3) Excellent Reliability 4) Great Appearance & Stature (Most common supercharger type for show vehicles)
Negative Points: 1) Sometimes Violent Throttle Response 2) Lower boost ratings at higher RPMs 3) Higher Than Normal Discharge Temperatures 4) Lengthy installation times
Manufacturer Availability: Allen Engine Development – BDS – Magnuson – B&M- Holley – Littlefield – Mooneyham – Weiand – Edelbrock
Holley’s Roots Type Supercharger
Screw Type Supercharging
Screw type superchargers are derived from the Roots type concept but with vast improvements for street use. Although from the out side, screw type superchargers may look a lot like Roots type superchargers, on the inside you will find a twin-screw design that compresses air unlike Roots type superchargers which pump the air into the motor. Screw type superchargers have an axial-flow design that compresses the air as it moves between the screws to create positive pressure without creating the heat that Roots type superchargers can create.
The Screw type supercharger’s ability to produce a dramatic increase of power from idle and through out the rest of the power curve make them a great choice for heavy vehicles, towing or commercial use.