PTS Flowbench Forum

Hi
Well I seem to have finally achieved an acceptable calibration of my bench after remaking angled manometer thanks to everybody who helped.
What I need to do now is work out whether the remote testing rig that I need to do flow work on my Flathead Ford V8 is OK or not (see photo). Question here is if I fit a calibration plate at the end of the hose as pictured and run up the bench to mimic flow rate @ 28" when the same plate is fitted direct to the bench the test pressure on the vertical manometer is less than 28" I guess what I am thinking at the moment is that the lower pressure is at the bench and that the actual depression at the end of the hose is 28". Is that a reasonable assumption? Lesser test pressure is consistent with the 2 calibration plates I have at the moment. If I need to hook up depression manometer to end of hose which is the other option how would I fit the pressure tap so that it would not be influenced by the flow.
Thanks
Grant

The pipe below your cal plate is going to have an effect on the plates Cd.

Personally, I would cal the bench with the plate sitting on top of the bench and test your part. This is probably the only consistent way of making sure your testing is repeatable from test to test. There has been some lengthy discussions on this in the past, I'll see if I can find them on the old forum later today for reference.

Hi Bruce
Thanks. I will have a read before asking any more questions.
Grant

Feel free to ask questions!

I'll search for the old discussion to add to any questions/discussion. Things can be hard to find in the old forum, I've been around the forum a long time and I still can't find things even though I know we discussed an item.

I have no problem re-hashing anything that was talked about in the past, sorry if my reply might have sounded that way

Hi Bruce
The written word isn't quite as good as a face to face discussion (thank goodness) didn't mean to imply anything with my comment just figured there would be lots to learn from previous discussions thats all.
I calibrated the bench with plate direct mounted on top of bench and then tested the same plate on the end of the hose what I found was that to recreate same flow reading from the bench I had to apply a different level of depression as measured back at the bench. This was repeatable with 2 different calibration plates. Bench top flow test @ 28" equals hose end flow test @ 25" test depression. If this works out with the new plates you are making for me I would propose to use the lower depression as standard hose end test pressure unless that is flawed thinking. Problem with the Flathead is the only way you can bench test is to cut the block in half basically so I need to find some way around the problem of hose end testing.
Thanks
Grant

Grant,

Two things 1, testing at the end of the tube will be off as you are simulating an orifice in a pipe this will effect the CD of the plate especially that ribed flex pipe. 2, can you fabricate an adapter that would use say 3" PVC with an oring and a 45° slip into the botom of the bore then fasten to the main sadle thus allowing you to draw from the bottom of the block?

Rick

Hi Rick
The fitting on the end of the hose plugs into the bottom of the bore as suggested. Are you suggesting shortening rig and sitting block on top of bench?
Thanks
Grant

This is what you want. You're testing for improvements in airflow. Get a good test baseline from the stock block and go from there.

This is how Piranios Antique Automotive does the Model A.
http://www.modelaparts.net/

For the readings to work, first set the bench up with the conventional calibration method. Then take the verticle reading from under the head when you attach the hose. If you leave it at the bench you will be measuring the depression of the head AND hose showing a lower than acual flow CFM for the head.

Here is the kicker. If it is done this way a head will flow the same from bench to remote. However, a calibration plate may not. I don't know how many hours I spent testing that.

Instead of a hose like in the pic with the Superflow bench, consider building a separate simple sealed box to mount the block on. Then set up detachable plumbing to connect the two.

Look here at mine.http://flowbenchtech.com/forum/viewtopic.php?f=3&t=15

Hi Chris
Is that the box to the right? I saw somewhere that Smokey Yunick had a setup where he had a flowbench connected to a sump? oil pan? ( not sure what term you use) bolted to the engine he was testing it was still connected back to the flow bench via hose. I have seen a few flathead test rigs where they run the manometer connection right to the connection point at the bottom of the block but I was concerned about how to fit the pressure tap to the hose without airflow impacting on it, the test box looks like away round it.
As an aside how do you access the old site I joined the new site and don't seem to be able to access old site.
I will have a look today at how a box might be configured,
Thanks
Grant