air flow #s ?

[Alan Roehrich]

Originally Posted by Kevin Panzino

Sorry, but I respectfully disagree. A flow bench which is not calibrated to measure true CFM is worthless for other than relative port work for your own usem and yes it wont correlate to other flowbenches which are properly built.

Good flowbenches will read identical. A SCFM is an SCFM, and a precision flowbench is just that, a precision measuring device that will be calibrated to indicate the exact CFM given the current atmospheric conditions. If two flowbenches do not read the same corrected flow, one of them is not of high quality, or is out of calibration. Period.

And correction between two test pressures introduces ZERO error. Its nothing more than the laws of fluid dynamics which are well known, established and accurate anywhere in this universe.

You are entitled to your opinion.

However, brand new expensive flow benches, properly calibrated, will not read exactly the same, especially in different locations, even with the same calibration orifice. Compensation factors are not perfect, either.

In talking to a couple of Super Stock cylinder head guys, who do heads for very fast cars, I learned that they have found things at 36" or more that were not possible to see at 28".

You may take that for what it is worth. I know them, and I know how fast their stuff is, so I have no reason not to believe them.