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Old 09-05-2010, 11:43 AM   #703 (permalink)
Phimosis
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Quote:
Originally Posted by Neo187H View Post
Has it been shown that the rotrex stage one unit can't flow more?

Or have they just not chosen to put a larger pulley on it and see? Sorry if this question has been answered previously, I don't think I have overlooked it in my reading through.
I would say the answer is yes, based on: http://www.power-enterprise.co.jp/ro...rotrex/C38.pdf

The unit is rated for 865 cfm of flow, compared to 1150 cfm rating for the Vortech unit used in the Stillen kit. That number is relative though, based on the pressure map. The pressure map in the above referenced .pdf file shows the efficiency range as a % efficiency. You can get it to make 11 psi of boost, but not very effieciently and the volume of air flow will be much lower than its max of 865 cfm. Or, you can go to the other end of the extreme and get 865 cfm of flow, but with no boost, which is also inneficient as a compressor. The "sweet spot", or peak effieciency, is where you are getting good boost and good cfm of flow. The rationale for using this smaller compressor is that you can gear it high and spin it very fast, so that it builds boost at a lower engine rpm, but then in the upper rev range, the boost doesn't keep building.... it just kinda plateaus. If you use a big compressor and spin it fast, you get too much boost at high rpm, potentially causing engine failure. If you use a big compressor and spin it slower so boost is ideal at redline, the boost level in the midrange will be much less than ideal and performance will suffer.
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