Impeller design

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I was wondering this: Does a radial impeller for a centrifugal supercharger help create more low-end by trading efficiency for vanes that help "push" the charge in? Just wondering.
 
you mean the ones that have just straight blades only, not curved blades like a turbo has?

I have always thought they look stupidly inefficient.
 
Well... since I am neither a scientist nor a supercharger owner/designer, I doubt I am an expert in this subject :roll:

However, I was just thinking to myself about how centrifugal superchargers and turbochargers work, and that was when I thought about that... thing they had at playgrounds... where you would get on this circular thing with handles on it, and you would cling to them as someone spun it. That's when I got to thinking, "Maybe there is a reason they still make straight bladed impellers...!"

What I figure is the straight bladed superchargers are designed to help increase mid-range boost by "pushing" the intake air as well as using the centrifugal force of the spinning impeller, whereas a curved blade impeller would be too aerodynamic to be able to do this. Of course, once the impeller gets to spinning fast, the "pushing" becomes "beating" the air vs. the curved blade's uh.... not-so-beating design? :?

The thought came across my mind when I saw this dyograph on a 04-06 GTO forum:
MAF001.jpg


The powerband is pretty darn flat for a Procharged GTO...

Anyways, just wondered what you guys would think of my thoughts... I figure that, since I am not looking for a drag-racing car, a centrifugal would be nice. Am I completely off, or do I have some logic stuck in there? :lol:
 
I (and others that I know) have had too many "belt induced headaches" for me to really seriously consider a belt driven supercharger again. They sure seem to work well when they ARE working, though. But a turbo is almost a "bolt on and forget it" ordeal.

I can't argue with the merits of a "positive displacement" supercharger, but the centrifugals are just not a great idea (IMHO).

If someone wants a centrifugal supercharger, may as well get one driven by a turbine instead of driven by a belt, as the spool up time is a LOT faster. :wink:

The really fast belt driven centrifugal drag cars have really high stall speed converters and MONSTER sized SC's with huge pop-off valves to prevent over boosting in the higher RPM's. That's just a lot of wasted HP lost in the form of bled-off air.

A turbo only works as hard as it needs to - - - No more, no less.
 
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