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flow bench setup 3

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anarchist

Automotive
Mar 23, 2006
7
hello all, i have just signed up and this will be my first post. i have looked at the threads for a while now and aplaud you all for keeping free education and helping others in you lives. rarly do i see the desire for anyone to help another if there is not monetary value or something in it for me attitude coming up. my hats off to you.

now on with my question. i have just purchased a used flow bench that is in good shape. it is made by internal dynamics and is a seventies vintage. my problem with it is that it does not seem to read rite. the verticle manometer that you would use as your baseline does not seem to pull a vacuume. the angled manometer that you would use to note your change seems to pull to much. this bench uses three d.c. motors with a single transformer and a verible resistor to control the flow. there is also a set of three connectors that you can plug the baseline manometer for different velosites as well. i have tried to plug the baseline into all different connectors with the same results.

my feelings are that someone has changed the lines around and i cannot figure where they go. the other option is that there is a restriction in the chamber that the head will sit on and not allowing the vacuume lines to breath although i feel that i have checked them and they seem to work. any ideas or does anyone have diagrams that i could see to get this to work. i feel every weekend that it is not working, the race car is going slower.
thanx in advance and remember that anarchy is not a bad thing, it is an awarness and awakening. sorry for typos.
 
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What you are seeing sounds about right.

The vertical manometer reads test pressure across whatever you are measuring. With nothing fitted over the test hole it will be impossible for the bench to develop any test pressure. Try placing a restriction there, and watch the test pressure rise as you pull more air through the restriction.

The sloping manometer measures airflow. Again with nothing restricting airflow, the sloping manometer will measure massive flow, and readily rise to maximum.

There is an excellent flow bench Forum that you might like to visit, I post there as "Tony".

 
You will need a calibrated orifice plate as a reference to get started.

The one used by Superflow is a thin metal plate (i.e. sqaure edged orifice plate) has one 1.875" hole and one .3125" hole. When you place this plate onto the cylinder head fixture it should flow ~255 cfm.
 
Greenlight is correct--but you will also need to control your test pressure--in order to determine your cfm----on the superflow bench--25" of test pressure is the calibrated number----for tests that require more or less pressure a correction factor is needed to achieve the actl. cfm--If you are only looking for a visual to any change and do not have a need to know the cfm you must still have a predetermined test pressure and hold it for each comparison test you run---
 
if i am not mistaken, the test pressure would be read at the verticle manometer. this bench does not have a selection of orfices like other flowbenches, it has three dc motors that are controled by a variable resistor. so i would assume that when i adjust test pressure, i would always set the verticle manometer to the same reading. if calibrated with an orfice plate, does that give me a specific reading at a certain rate of flow?? where would i set my verticle manometer as it could change with the elect. resistance??
 
if i am not mistaken, the test pressure would be read at the verticle manometer.
---YES--IS THERE ONLY ONE OF THESE??

this bench does not have a selection of orfices like other flowbenches, it has three dc motors that are controled by a variable resistor. so i would assume that when i adjust test pressure, i would always set the verticle manometer to the same reading.
----I AM GUESSING HERE BUT I WOULD THINK YES---

if calibrated with an orfice plate, does that give me a specific reading at a certain rate of flow??
---i WOULD THINK SO----

where would i set my verticle manometer as it could change with the elect. resistance??
--AGAIN I DO NOT WANT TO PERTEND TO UNDERSTAND EVERYTHING ABOUT FLOW TESTING---
--BUT IF YOU NEED CFM YOU WILL NEED TO GET SOME STANDARD ESTABLISHED TO KNOWN SETTINGS---IT IS EASY FOR ME BECAUSE ALL THE TEST SETTINGS CAME WITH THE MACHINE---ALL MY CAL. IS BASED ON 26" OF TEST PSR---
 
anarchist, your best bet is to join the Flow Bench Forum at the link I posted above.

There is a wealth of information and help is readily available, as well as all the formulas needed.
 
there is two verticle manometers on this bench, unfortunatly i do not have a lot of knoledge about flow benches and this one is different than others by quite a bit. all your info is great and warpspeed's link has hepled me out, but there is a lot that is still fuzzy. i have not been able to play with the bench much yet but have set time aside this weekend. i have just recieved some manometer fluid in the mail on friday and will be changing out whatever the bench had in it before ( i think it was rubbing alcohol) so i will let you all know what happens. thanx,
 
if you would like to talk feel free to contact me
witmfg@cox-internet.com
 
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