Here's the other canadian engineer who prefers turbo's to superchargers and what he said on CC.com forums, at least the most relevant part. To paraphrase:

Quote:

A home built turbo kit is going to be THE most cost effective way to make good power. But it's very easy to screw it up. Due to the stresses and heat invovled, not to mention the fact you have another independent heat engine operating (or two!) under the hood, there's just more to think about.


However, when you do it right, they work great. Just look at Porsche. They engineer them right, and the system is just as reliable as a NA engine.


quote:
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My other thought is for power adders on the track, the big teams (Audi, Porshe, etc)seem to have good results with them vs SC's (and other than the Steeda car, I haven't seen a centrifugal out there).
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SC's just can't compete, plain and simple. They are drawing power off the crank to power the compressor, and the turbo uses waste heat. Not to mention boost control.


I've often said, superchargers would be great if you could take a centrifical blower, gear it up to make boost early, but then have a CVT transmission to slow it down at higher revs, the idea being to tailor the compressor speed to provide the right amount of boost early, and hold that boost until redline.


The fact is, turbos do that already, with a much more simple system, and again, you can't ignore the fact that they are using waste exhaust heat instead of crankshaft power.


Roots blowers are horribly inefficient. Centrificals have peaky power delivery. Nothing down low, then too much up top.


A proper turbo should be able to supply full boost below the torque peak, and hold it steady all the way to redline. If you're really smart, you can have an intelligent controller that varies boost with rpm, and can give you an absolutely flat torque curve. Hit a healthy boost at max torque, and push harder as you move past the volumetric efficiency peak of the engine.


What's funny is, 90% of the supercharger fans I see on the Focus boards ONLY do it for the "golly gee whiz" factor of having "that cool blower whine", or because they saw it in Mad Max or some stupid [censored] like that.



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