Tractorsport Flowbench Forum Archive

Posted: **Tue Nov 16, 2004 6:59 pm**

just wondering what some more experienced people might have to say about this

i have an old 8-71 blower sitting around the shop, and have been considering that as a decent pressure(or lack of) source for a flowbench

I know i would have to have pressurized oil fed to it, but thats easy, i was thinking it could be driven with an electric motor

my only reservation is that like Bruce I would mostly be testing this on a garden tractor pulling engine, with that kind of an air supply I could have a lot of flow or a lot of pressure

My question is this, would it be possible to run it slow enough to get the lower flow numbers that I would like to be testing at, Or would I just always be doing ultra high pressure readings?

Matt

Posted: **Tue Nov 16, 2004 7:54 pm**

Ah . . . won't work sell it to me and I'll dispose of it for you

Whatca can do is add a bleed valve into your flowbench so you can bleed off the excess vacuum you don't need for testing at lower flows. I'm not sure on slowing it down, I wouldn't see why that would not work either? They do it on drag cars by increasing or decreasing pulley ratios, but then again thats still high pressure.

Posted: **Wed Nov 17, 2004 1:03 am**

I have never tried this myself, but see no reason why it would not work really well. If it still has the twisted rotors in it, pulsing should be quite low.

Posted: **Thu Nov 18, 2004 8:21 pm**

using something like that, and yes it has the twisted rotors, would you need a plenum or could you just run 4" tubing directly off it?

I'm not really sure of the need for a plenum on a flowbenchexcept to help air stabilization, but that can be acheived by other means also, maybe someone could explain why there is a need for a plenum?

Posted: **Thu Nov 18, 2004 11:41 pm**

Why not try it and see ? Fit a pipe stub and orifice plate and see if it can pull a steady pressure/vacuum without pulsing.

My own experience with roots blowers on engines, is that they do pulse and create quite a drone under high boost, but I have never tried one in a flowbench.

Tractorsport Flowbench Forum Archive

pressure source