Digital Manometers Bench Reads inconsistent flow measurement

[ebug]

All,
I just started using my bench and have decided to use a pair of inexpensive digital manometers.

Last night I was comparing the flow numbers of a pair of 2-stroke reed valve assemblies. I tested both candidates at 12", 16",and 20". As expected the delta was greater at the higher depression numbers. When I converted all the numbers to 28" I found that the actual flow at 28" was higher as the test depression pressure went up. I was expecting the numbers to be fairly consistent once converted to 28".

Can someone help me pinpoint the problem in my assumptions please.

FYI,
I am using a modified version of the spreadsheet located on this site. The mod is to include the math on each row so I can build a chart. I have triple checked the formulas and believe I have transcribed them verbatim.

Thank you in advance,
Rob

[ebug]

This is a screen shot of what I am referring too.

[ebug]

Well after a few days rest I have it all sorted and I feel like a klutz.

I was trying to look at this like I had a fixed restriction in the reed plates, but as we all know the reeds bend as these the depression increases. That creates a larger flow window. That is why my @28 numbers were getting higher.

Rob

[Brucepts]

As you found out taking a day or two can sometimes make things "click" in your brain and you get that "ah-ha" moment!

I've done that more than a few times working on a flowbench issue. Rick can attest to that with my lack of willingness years ago to leave the pitot style flowbench for the orifice design. Took me awhile until the orifice style "clicked" in my brain!

Glad you figured it out!

[86rocco]

You've not only answered your own question, you've come up with a method of comparing and evaluating different reed valves.

Anyways, it's gratifying to see that my old spreadsheet is still making the rounds and being put to good use.

[Brucepts]

You've not only answered your own question, you've come up with a method of comparing and evaluating different reed valves.

Anyways, it's gratifying to see that my old spreadsheet is still making the rounds and being put to good use.

Has been indispensable to the forum users!!!!

[86rocco]

Has been indispensable to the forum users!!!!

Thanks Bruce.