Flow Test
I was just wondering what the actual process of flow testing a head was...
I have head a head ported and polished, but it was never flow tested. Lucky, the head performed very well without being tested.
I thought that as long as the ports were bigger and smoother, they would always be better than a stock port. But i've heard that some port & polish jobs actually perform worse than stock!
So, if anyone can chime in, it would be great.
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yeah, oversizing can lead to air density build up in the wrong areas of the head. if you're talking about honda heads, they come pretty much how they should from the factory. all you should have to do to them is smooth the runners and knife edge the dividers. little changes make big differences, and big changes can mess up a head. as far as flow testing, they put the head on a flow bench and measure the air compression throughout. it helps the machinist know where choke points are in the channels and around the valves for more precise builds.
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good callOriginally Posted by integra82786
a flow bench shows a porter how much air the head can flow at different amounts of lift of the cam. the size of the port is very important because you need to find a equal medium for flow and keep velocity of the air. most honda heads require more than knife edging the runners and cleaning and smoothing the ports. a ported head won't flow crap without the right valve job. you also need to deshroud the valves to keep airflowing smoothly do some bowl work to help prevent detonation, and keep a eye on the approach angle to the valves. all of these things add up to the difference between a good ported head and a paper weight.
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