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Old 09-29-2011, 09:06 AM
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Originally Posted by klx650sm2002
Hi all
Bit of a newbie question, here goes, when quoting gas flow figures for throttle bodies, ports, mufflers etc. how many inches of H2O are they measured at ?
Thanks in advance
Clive W
Generally speaking, 28 in/H2O- BUT you need to be certain of what the depression actually is because sometimes figures derived from a different depression will be used in advertising (for example) to "inflate" the figures, or flow at a higher depression will be compared to another manufacturer's flow taken at some lower depression- again to inflate the claims.

There are formulas to correct different depressions to each other or to a 28 in/H2O 'standard', as you may already know. Like to convert 25 inches of water to 28 inches of water: multiply by 1.06.

Some info on flow benches and how to fabricate them-
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