Curved vs Straight Blade Impellers - Centrifugal Supercharger Comparison
 Curved VaneCentrifugal Supercharger |
 Inefficient Straight BladeCentrifugal Supercharger |
Looking at these blowers it is hard for the untrained eye to pick much of a difference between them. Like a lot of other performance parts though the main changes lay under the skin. In the case of Centrifugal Superchargers it is very easy to purchase almost identical looking products with vastly different levels of performance.
The real key to the power potential of a Centrifugal Supercharger is hidden under the front cover of the blower itself - it is of course the compressor wheel.
 Curved Vane Compressor76% Efficient |
 Straight Vane Compressor50% Efficient |
There is no doubt about it - the curved vane impeller comes up a winner under any type of comparison with the archaic straight blade design. All you have to do is remember that the job of the compressor wheel is to move a volume of air out of the blower snout as aerodynamically as possible....Now what is more aerodynamic....a carefully designed compressor blade? or the blower version of a house brick?
These efficiency figures were ascertained on a flow bench in America, and indicate that you either have to rev the straight bladed blower 20% harder to achieve the same boost (more in reality due to higher crankshaft losses and hotter air temperatures), or just put up with 20% or so less power and reliability.
The choice of course is yours... but why settle for a design outdated some 30 years ago?