Curved vs Straight Blade Impellers - Centrifugal Supercharger
Comparison
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.
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 but why settle for a design outdated some 30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?
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