Sorry for not clarifying - what Keydiver said - each revolution has only two cylinders sucking in air, while the others are compressing/combusting, so it comes out to about 998.5 cc's per rev of the crankshaft. Also, lbs/min isn't quite the right measure to use - that would be more like "mass efficiency". Convert to liters/min or cc's/min and the logger formula will work for "volumetric" efficiency (since you're not taking into account temperature and density).
Here is a good conversion from MAF Hz output to L/min for a 2G MAF
, which incidentally credits Jeff
. There are others out there for 1G and 3G/Evo MAF Sensors as well. If you're using a translator, you can get pretty close by just using the converted output.
Note that the VE quoted is usually a "peak VE" for bragging rights. The VE will be different for every part of the RPM curve (and throttle setting, but I doubt you want to go there)
If you're trying to use this to set up a speed density system, I'd suggest getting the car running and tuned using some type of mitsubishi MAF first, since the Karman type is one of the most accurate as far as airflow sensors go. Take the logger readings from all points in the RPM range and plug them into a spreadsheet.
For example, 835 Hz on a 2G MAF is about 6000 liters/min. At 4000 RPM, that's 1.5L/rev. If you're running 15psi in the intake manifold (PR of 2.02), that gives you a base VE of about 74.2% (if you include the turbo, your overall VE is 150%), but only in reference to the engine at 4000RPM with 15psi boost - changing the boost level can change the VE, since we're talking about airflow through tubes, pipes, intake, head, etc. There is still error in the calculation (it could be off by 2-3%) but it should be decently close.
There's no good way of calcuating the base VE of the engine without all the intake piping, short of attaching the MAF directly to the throttle body (which of course eliminates the ability to take into account the losses from forced induction)