airfuelEddie wrote:I aksed the instructor if this would affect the flow and he said it shouldnt that much.
Thank You Fabien! I am always impressed by your knowledge! BTW, Fabien, I have a packet in the manual I brought home. It contains 2 pitot tubes to measure airflow stagnation and velocity. It also has a chart with density/temperature . I am reading and it seems very important to port development! I can find the airflow stagnation points in the port. I have to say, this flowbench can suck up to 1000 CFM's and it will literally pull your hand in the orfice! I had the airflow calibration set to 300 CFM when I tested that Intake/Exhaust port. You can put the airflow setting as close to what you think the port will flow maximum. This way the readings are more accurate because the parameters are within it's range of measurement. At least thats what the 'directions' said, I'm still learning so much. I want to graph this all on paper, then bring it home and set up my own file and record the changes on the PC. Thanks for the input.fbernard wrote:airfuelEddie wrote:I aksed the instructor if this would affect the flow and he said it shouldnt that much.
I think it won't matter much too.
If you were measuring air flow through this tube, going from 4.25 to 4.38 would be a 6.2% increase in section, and so a 6.2% increase in flow at any given vacuum.
But what you're measuring is air flow through each valve and the port which precedes (or follows) it. The shape and size of the simulated combustion chamber is not too relevant, as long as the pump can create enough vacuum or pressure to take the maximum measurement.
I think the length of the tube would have a much bigger influence over the results than having a tube with a 4.38 bore.
I asked him about that Ian and he suggested modeling clay. All I had at the time was silly putty, kids crap. It crumbles to easy. I'm gonna pick some up today at wally world. You have to have somethng that mimics the walls, roof ect exactly, only something thats pliable yet sticks to the sides all the while conforming to the shape of which each port has minute differences so a tooling plate will only be a burden. Plus when I start 'hogging' out those ports I'll need to expand it all the way around the circumference of the shape. I'll keep you posted on what I find out and the results after I get this figured out. BTW, what is perspex?ianandjess wrote:add 30% to those figures you got & theyre not as bad as you thought
can you shape a piece of perspex to give the desired effect 1 of the aticles i read recently sugested doing it that way
cheers ian