V6 iron cylinder head (Page 12/12)
Will JUN 14, 05:59 PM

quote
Originally posted by lou_dias:

Classic.

What I couldn't convey then that I can now is about using water to flow bench. Water has a lot more mass than air and doesn't like to change direction. Air simply follows to the lower pressure area regardless of which direction that is in. Doesn't care so much about direction change and that's why your can increase flow with polishing more than a mild port with a rough polish.
So flow benching is a good guide to finding restrictions in the grand scheme of things but air will still outperform the expectations of a flow bench in many cases.

This goes back to the philosophical differences me and Rei and the OP have about the intake vane. I believe it's there to balance pressure around the valve as do a lot of engine builders but a flow bench will tell you that you increase flow by removing it. So I digress...




I've heard of people using glycol (antifreeze) mist and UV light to visualize the flow paths.
lordfiero JUN 18, 04:54 PM
Nah, not very healthy to inhale antifreeze mist..
lordfiero JUN 18, 05:05 PM
Blocking the upper outer part of the LIM proved to boost the flow through all my different MIM test runners. I think the stock shape gained the most.
When measuring the LIM alone this may seem as a reduction in flow but this to direct the air from the MIM to the LIM, so the gain is only seen when both parts are connected.

Will JUL 07, 09:44 AM

quote
Originally posted by lordfiero:

Nah, not very healthy to inhale antifreeze mist..



Maybe it was ethanol? Much more fun in inhale
Will JUL 07, 09:47 AM

quote
Originally posted by lordfiero:

Middle Intake Manifold, MIM.. This was a big surprise.. I read many concerns about the goose neck on the upper intake manifold, but why worry about that when the MIM runners cant supply the heads with sufficient air anyhow.
Flow is down 20% with the setups below.

Separate MIM prepped for optimum measurements


Together with Fiero UIM


Together with Camaro UIM


The flow performance was so bad I had to measure the LIM again but with the same reults
I dont think the MIM can be fixed by porting out the stock shapes any longer. This is a problem..



Maybe this is something to try:

http://www.fiero.nl/forum/Forum2/HTML/142715.html

[This message has been edited by Will (edited 07-08-2019).]

lou_dias JUL 07, 02:27 PM

quote
Originally posted by Will:
May this is something to try:

http://www.fiero.nl/forum/Forum2/HTML/142715.html



I'm sure there may be some happy medium there where perhaps I could have drilled equal sized smooth holes in the walls and polished them and deburred/smoothed everything out and perhaps not lost as much mid-range and kept most of the top end gains but desperate times called for desperate measures.