Ok... i understand that you want your heads to flow alot of air.. but you want it to flow alot of air in as minimal time as possible (acceleration/velocity... cfm/s^2 ???)

So how is velocity measured, can a standard flow machine measure this?

Sorry for all the how stuff works posts, just tryin to get a good understanding of how this all goes together...

 

Mike, Most porters measure velocity on a flowbench with a probe fashioned from a hollow tube connnected to a manometer, which is simply a liquid filled vacuum gauge. They then stick the probe in the port to measure velocity at different points. The problem with this is its basically irrellevent data. What matters most in velocity probing, is the velocity around the valve roughly every 45 degrees and every .100" of lift. You do this by taking the exact valve you use in the head, putting it in an EDM machine, bore a hole down through them stem and an intersecting hole from the 45 of the valve seating area and hook that to a manometer. With that being said, a regular guy can compare relative velocity between the same head type by taking the port flow at each lift and dividing it by port volume which on your head is around 225cc intake port volume. Good luck, Brian

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Brian Tooley:
<strong>Mike, Most porters measure velocity on a flowbench with a probe fashioned from a hollow tube connnected to a manometer, which is simply a liquid filled vacuum gauge. They then stick the probe in the port to measure velocity at different points. The problem with this is its basically irrellevent data. What matters most in velocity probing, is the velocity around the valve roughly every 45 degrees and every .100" of lift. You do this by taking the exact valve you use in the head, putting it in an EDM machine, bore a hole down through them stem and an intersecting hole from the 45 of the valve seating area and hook that to a manometer. With that being said, a regular guy can compare relative velocity between the same head type by taking the port flow at each lift and dividing it by port volume which on your head is around 225cc intake port volume. Good luck, Brian</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Wow <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> kickass you even referred to me by my first name <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> (alot of shops dont seem to remember their customers full name ... or at least is my experience <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> )

Ok... while alot of that info I don't fully understand (hey, im a computer programmer by trade... just started learning about cars 2 years ago heh) it boils down to the velocity equals flow @ x lift / 225cc (for TEA 5.3L S2 heads)?
So at .600 lift my heads flow 1.35 (flow was 303)/t^2? where t is the measurement of time? what time measurement is generally used? I'm guessing I could prolly find this by looking up "manometer" ? (not sure what a mano equates too... don't think i heard of it so it must be a VERY exact measurement of time (10^15?))

Thanks Brian!

Mike

<small>[ November 14, 2002, 12:10 AM: Message edited by: horist ]</small>

 

Manometers are used to measure the pressure of a gas (eg. air). Not a time measurement.