This type of supercharger is basically a turbo charger that is mechanically driven by the engine via belt instead of exhaust gases. Similar to a turbocharger, a centrifugal supercharger needs to spin at high speeds to achieve maximum boost pressure (up to 60,000 RPM) as a result you get "supercharger lag" but unlike a turbo, the ramp up in boost is very linear and predictable.

Its construction is very similar to a turbocharger in that it uses an impeller to suck air in and compress it in the housing using centrifugal force. The advantages of this design is its light weight and compact size making it a great candidate for a variety of aftermarket applications. For example, this setup takes up slightly more space in your engine bay than your traditional AC system.

The lack of low-end torque coupled with predictability in boost build up makes centrifugal superchargers good in traction limited scenarios such as circuit racing. Moreover, Due to its low inertia / friction it its the most efficient of the three types of superchargers. However, if your have traction ie prepped drag surface, this can lack of low end power is a negative attribute.

This is where it all started with forced induction. The Roots brothers invented this design as an industrial air pump well before the motor car was invented. After the motor car was invented and subsequently the thirst for more power output was desired, engineers quickly turned to the roots supercharger for charge air to increase output. Although the technology is now historic, its still getting used today primary by EATON. However, heavily altered from the original 2 straight rotor 3 lobe design.

While roots and twin-screw superchargers are almost indistinguishable from one another by looking at the casings a lot is deferent inside. However, they are more similar to each other than they are to a centrifugal supercharger. 

A roots supercharger works by using the engine to rotate two lobed shafts in opposite directions within a casing to draw in air and pump into the intake manifold. However, it does not compress the air within the its case, the compression happens in the intake manifold as the supercharger provides more air than the engine can take it in.

Due to its size, the Roots supercharger doesn't need to spin very fast to achieve full pressure (boost). By 2000 engine RPM the roots supercharger is already making full boost giving the engine a seamless supply of charge air with no lag.

However, the roots supercharger is the slightly less efficient of the three. The downsides of this type of supercharger is slightly more parasitic losses compared to a twin screw and slightly higher charge temperatures. 

The roots however didn't go without improvements, and as of late, EATON came out with TVS (twin vortices) 2650 roots type supercharger witch is also the Roush 2650. The design now features 4 lobes instead of three and a more aggressive twist. This bridges the gap between the roots style and the twin screw. While many tests show that a twin screw is still more efficient, its only in extreme applications that the efficiency is pronounced enough to make a deference. For example, the deference is negligible on a Coyote Mustang whether you go Roush (roots type) or Whipple (twin-screw). Its not until you get the extremities of a 1000 WHP and above is when you will start seeing the advantages of a twin screw. Most factory built engines will fail before you get to that level of power anyways.

So why do they still manufacture roots style superchargers?

Manufacturing cost, the twin screw is slightly more expensive that the roots to manufacture. Our offerings from Whipple are slightly more expensive than Roush.To put into perspective, the latest s550 Mustang Shelby GT500 uses a roots style supercharger, most likely to keep costs down. 

*note* we supply and install both roots (ROUSH) and twin screw superchargers (whipple)

Last but not least, is the Twin Screw Supercharger. It follows similar principles to the roots type supercharger, however it builds on that design by incorporating two different rotors, a male and a female that are machined with very tight tolerances to trap air between each other and compress it into the intake manifold. 

Although a little more expensive than the roots type superchargers, twin screws do offer more efficiency, less parasitic losses and cooler charge temperatures. While these positives are slight on street applications, in extreme scenarios the gap widens between the two types of superchargers.