Tractorsport Flowbench Forum Archive

Posted: **Sun Apr 11, 2004 1:45 pm**

What are your thoughts on FlowBench Test Pressure ?

or what Test Pressures are you Flow Testing at ??

Posted: **Tue Apr 13, 2004 4:51 pm**

I thought 10" of water was a good test pressure because I thought it would show up small things that would be overcome by changing to a higher pressure but I have just been reading Smokey Yunicks power secrets book and he said the opposite, that big port changes didnt make much of a difference to measured flow at 10" but at 28" there was a lot bigger measured difference. He did all his work at 28" depression (he also had a 100hp electric motor and a huge roots style blower to provide the air). Apparently above 28" the percentage change didnt increase relative to the change in test pressure.
It's a real can of worms though as every different person you speak to seems to have a different idea, I suppose its a matter of test and see what works for yourself.

Posted: **Thu Apr 15, 2004 4:38 pm**

"My Opinion" is to be most usefull, you would test at the vacuum pressure that the tested piece ACTUALLY sees durning normal running conditions. Now determining what that value actually is...... GOOD GUESS!

Posted: **Thu Apr 15, 2004 9:21 pm**

I think 28" is a minimum for serious work.
If your bench can test at higher pressures than this - it's probably good to do it.
I have heard that Nascar teams like to use 40" +, and Dart have just had a new bench built that is designed to flow at 60".
This is for intakes - on the exhaust you can't get anywhere near to approaching operating pressures with a conventional bench.