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Old 01-11-2005, 10:00 AM   #1
root
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Default Calculate VE from MAF readings?

Seems like it should be possible to calculate the VE from log files if we have the RPM, MAF, and AFR readings. Has anyone worked out the calculations or am I missing some bit of info?
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Old 01-11-2005, 10:18 AM   #2
hippy
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Someone has. I was reading the other day where someone said their wrx had a 162% efficiency at peak torque(with 14.9psi of boost). Here's a link.....

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Old 01-11-2005, 10:25 AM   #3
root
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Very interesting. Thanks for the link.
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Old 01-11-2005, 10:29 AM   #4
root
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I was thinking you would have to take the volume of the fuel entering the engine into account as well as the air. But maybe with such a small amount of fuel compared to air it would be negligible in the calculations.
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Old 01-11-2005, 11:12 AM   #5
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i think thats jblaines site if im not mistaken.
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Old 01-11-2005, 03:48 PM   #6
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Roger that.
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Old 01-11-2005, 08:09 PM   #7
Jon [in CT]
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Quote:
Originally Posted by root
Seems like it should be possible to calculate the VE from log files if we have the RPM, MAF, and AFR readings. Has anyone worked out the calculations or am I missing some bit of info?
You don't need AFR. You do need ambient pressure and temperature. You also need to know the volume of the combustion chamber when the cylinder's at TDC. And, of course, you need the cylinder's swept volume (displacement). With these values, plust RPM and MAF, you can calculate VE from log files. For best accuracy, collect ONLY RPM and MAF.
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