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Old September 14th, 2005, 05:05 PM
Ormand Ormand is offline
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Efficiency vs Mass flow

Quote:
I'm curios how feeding more air through the motor is naturally better if its not as efficient
Well, if you start with an engine, with no blower, how much can you improve efficiency by increasing compression? Maybe 10%, depending on the initial compression ratio. Higher compression gives higher thermal efficiency, but once you get to about 8 to 1, or 9 to 1, the gains fall off, real fast. For example, doubling the compression ratio, from 10:1 to 20:1 improves thermal efficiency from 0.60 to 0.695, and you obviously can't go THAT high! On the other hand, by going from zero boost to 15 pounds, you can almost double the mass flow. By going the 30 pounds, it's almost tripled. (IF you have a perfect intercooler) So, there are small gains to be made by increasing the compression, but huge gainst to be made by feeding more air/fuel. 10% vs 100%, or 200%.???
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