PTS Flowbench Forum

Here's another ancient pic.

Bench wasn't totally finished from the mods I did to make it work right. I'm using a single orifice. I removed the rotating disk and made a new one with just one orifice. It works well for what I do. Digital meters and the size of the orifice make it read accurately at low lifts without having to change ranges.

I used both FP1 and PTS meters. Both work fine.

A little video http://www.cavanaughracing.com/Porting.html That's a PTS pitot tube but the metering at that point in time was FP1. Pre PTS DM days....

I'll say this. If you get your rotating disk to seal up properly [and I have no doubt that you can], get Bruce's calibration plates and modify the bench design as I indicated, you should be in good shape. If you haven't built the cabinet yet, MAKE IT LARGER. The bigger, the better.

Couple of links for you:

http://en.wikipedia.org/wiki/Orifice_plate

http://www.efunda.com/formulae/fluids/c ... wmeter.cfm

http://www.flowmeterdirectory.com/flowm ... _calc.html

Larry, thanks for the pics and I did read before about your bench top mod. Also thanks for the link to your site because I actually own a KZ1000A which I bored to 1200cc and got some cams from Greg Cope for it years ago.Rode it everywhere and had later model GPZ fuel injection on it. I'm actually now restoring the bike to as new condition. I'm sure I'll be having a go at the cylinder head on this bike. I have about 7 spare heads here from KZ900 through to the later GPZ and I think I have a ZX as well. I also own an original Eddie Lawson Z1000R.


Bruce, I don't see where the thickness of the plate is in the calculations on those sites. To be honest I can't even remember how to do calcs like that.
I did find a site that had the Cd listed for the diameter or the hole verses the plate thickness.
Here is a picture of what I found.
D/4 =0.62 where D is the diameter of the hole . So I guess that means if you have a hole that is 1in then thematerial can be up to a max of 250 thou and you will still get a CD of around 0.62.
Another is 2D to 3D for a Cd of 0.82
This has all become very interesting, just a little more than actually building the bench at the moment!
I guess only testing will show the true results.

Where did yo get this chart i would like to read about this.

Thanks

Rick

Rick,
I think this came from the SuperFlow web site. Here is a copy of their latest pdf from their flow bench support area:

It was not from superflow, I'll have to search for it because I looked at a lot of web sites

http://www.mcnallyinstitute.com/13-html/13-12.htm

10sec Google search . . . for the graphic name

I think what we need to keep in mind is that the graphic there seems to be for liquid. It refers to gallons per minute. Liquid is basically non-compressible and gases, such as air, are compressible. From what I can gather that does make a difference in the way it flows.

What I am thinking of doing is building a dual chamber box with a divider in the middle for orifice to simulate a flow bench. The I will have one side made of clear plastic. Then flow smoke through and see if it will actually show the vena contracta and see if I can calculate it that way.

I do not know if it is worth the effort or not.

John

Engine Airflow by H.B. has the same orifice information. Pg 52 - 53.

No,

What i was looking at was the effective principles of orifices and CSA all these example show the CD for the same CSA but look at the progression of the CD. The lower right hand example truly supports Larry Widmers theory on exhaust port. I would like to study this so as to incorporate these effects into a port, Would we all not want a port that can flow 1.5 times our minimum CSA?

Rick

Sorry did not mean to hijack the thread.