Supercharger Performance and Engine Performance Parts

Posts Tagged ‘Whipple’

The whipple supercharger is a unique and very practical chager. The unit is a great compromize between a positive displacement supercharger (that creates boost pressure by over pumping and over feeding the engine with air) and a compressor (similar to a turbocharger) that compresses the air inside the supercharger housing before sending it out to the charger piping. 

The unique three-five design of the whipple screw clearly showing how the lobe from the three lobe screw tightly fits between two lobes from the 5 lobe screw to compress the air for inter-screw compression.

The secret to this style of ‘hybrid’ blower is the two intermeshed rotors of different lobe numbers (see illustration). The combination of an intermeshed 3 lobe and 5 lobe rotor means that the rotors inside the housing are operating at different rpms with a ratio of 5:3 to keep the rotation of the lobes (3 lobes to 5) in synchronsim. This complex design allows the rotors to capture air (in its natural volume) from the back of the blower housing, and push it foward as the screws rotate. As the air is moved forward it is captured and compressed between the intermeshed rotors as well as being pumped (in positive displacement) from the inlet port at the back of the charger housing to the outlet port near the front. 

Because of this unique design, screw style chargers are able to outperform simpler rotor based chargers in two aspects:

1- The blower is able to acheive a higher pressure ratios because the compression is combined between positive displacement (overfeeding) and between direct compression of the air (inter-screw compression). 

2- Since the air is compressed inside the housing, the housing is able to ingest and move more air (higher CFM ratings) for a similarly sized roots style blower. 

So how is the whipple best used. Some people are interested in SIGNFICANTLY boosting their small displacement motor to make it not only have better low rpm torque but also unrestricted peak RPM power. In two of our articles (one, two) we have talked about how you can combine a typical roots style charger for low rpm instant boost, with a high rpm solution of turbocharger or even a centifugal supercharger that is sized proparly to elevate your motor to the required peak psi -- that above which your typical roots style supercharger may not be able to provide effeciently.

Well here’s the whipple solution. If you use a whipple charger, then you have the best of both worlds, you have a positive displacement charger that has no spool up lag, as well as internal compression allowing you to achieve high PSI levels without the need to for overspeeding your blower to do so. 

So, with the use of a whipple charger you can have a fairly flat torque curve from zero to redline giving you very predictable traction and launch control (which is why whipples and other screw type chargers are popular in drag racing or coming out of corners in road coarses). A predictable and linear torque curve also is more forgiving to overgeared cars and more forgiving with different driving styles. 

A video of a whipple-charged GT-500 mustang and dyno showing the infamous flat torque curve…

Here is an overview of whipples available chargers:

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Whipple

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