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Im new here, first question, converting flow numbers

Posted: Sun Oct 21, 2012 5:34 pm
by MJCustom
Hi, im in the process of building a fixed depression flow bench.
Im waiting on my metering plates to be cnc machined so currently its just floating depression.

i have a head that has been flow tested on a digital super flow.
iv done some extra porting to the exhaust and recorded the before and after results on the vertical nanometer.

its very promising. my question is for eg if at 12mm lift the gauge used to read 16.45 inches and now after porting reads 12.44 inches can i assume that it flows 32.2% more? (16.45/12.44=1.322)

thanks in advance.

Jason

Re: Im new here, first question, converting flow numbers

Posted: Sun Oct 21, 2012 10:33 pm
by 86rocco
Unfortunately, that's not quite the way the math works, the relationship between flow and pressure drop is NOT linear rather, it's a squared relationship, Flow squared is proportional to pressure drop so the the correct calculation would be √(16.44/12.45)= 1.15 or 15%.

Re: Im new here, first question, converting flow numbers

Posted: Sun Oct 21, 2012 10:49 pm
by MJCustom
Oh thanks for that.

15% still sounds good to me. The nanometer showed the same pressure drop at 7mm lift as the old port at 12mm lift so
Hopefully that equates to good things!