I'm looking into purchasing a flowbench but don't know what they cost, what features to look for, and whether or not anyone knows of a used unit for sale.

I don't have any information for you, but just noticed that you are from Virginia. Whereabouts? I am in Centreville.

Good luck with your search.

Here are some links to read up on. http://www.govictory.com/How%20To/FLOWBENCH/FLOWBENCH.html http://www.superflow.com/support/support-flowbench-faq.htm http://www.theflowshop.com/realaudio/real.html http://www.spiritone.com/~eoa/Cars/Flow_Bench/Flow_Bench.htm http://www.audietech.com/
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 Origonal owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

Thanks David, I see I've got some reading to do. Have you or anyone else here actually built a flowbench? I can probably get a positive displacement blower for little or nothing that will flow roughly 700 CFM at 28" H2O.

Boodlefoof, I live just west of Richmond.

I've thought of building one but try NOT to do it. I think it would totally distract me from running the car cuz I'd be tweaking the heads!

I really want to know the actual flow of things though. Even if I don't have super accurate numbers compared to others, if the numbers are consistent for me, they would be nice.
There is also a "flow quick" that can work pretty good. But I think you can build your own for about the same or less money and it will work better in the end.
The machine out of the PHR magazine article on this web page is the one I like... http://www.spiritone.com/~eoa/Cars/Flow_Bench/Flow_Bench.htm
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 Origonal owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

[This message has been edited by davidpozzi (edited 03-08-2002).]

I found another one. You can buy plans for a flow bench from
Powerflow Engineering
PO box 216
Rooseveltown
New York, 13683
613-937-4123

They sell photocopied hand drawings and photocopied somewhat blotchy photos of a flow bench with details on construction of it.

From my reading, I think you need a flow bench with a selectable orifice in it like Superflow does it to have any accuracy.
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

Building your own flow bench really isn't a very big deal. As long you are half-way mechanically inclined you can pull it off. The materials required is basic, you can make your own sharp-edged orifice plate when you find the dimensions you need, or you can have one made.

I am not going to get into any specific details on how to do this because the information is vast and sometimes deep. But I will give you the best resources. I suggest your first investment be David Vizard's book "How to Build and Modify Small Block Cheverlot Cylinderheads". The next will be R.W. Miller's Book "Airflow Engineering Handbook". This one is expensive I have seen it priced for $134.00. Check on www.half.com (http://www.half.com) periodically for a used one.

With the books above you will be a savvy and knowledgable head porter.

I don't want to become a head porter, but would love to be able to compare heads and flow stuff like air cleaners, etc.
I've been wondering about how they figure out the percent of flow for the sharp edged orifice. Any info on that?
Visard kinda glosses over that "little detail" in his books. He just shows a ruler scale inclined at 30degrees for percent and does not explain how to convert inches to percent.
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

Found the Miller book on Amazon, used for $51.
Thanks for the lead.
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

The pressure difference across an orifice varies with the square of the velocity of the fluid flow. Thus, a formula is needed in order to create a percent flow scale for the manometer.

I would think that it would be convenient to create a scale that would directly indicate CFM for each orifice used (at a fixed test pressure), and just change scales to match the orifice being used. This would save the step of converting each reading from a percent flow to CFM.

I've been meaning to get the Visard book, I should probably go ahead and get it.

The way I understand it, the percent scale is the same for any orifice at any pressure drop, that a minimum of 5" of pressure drop should be used.
The percent scale is logrithmic? or whatever,- squared like you say. BUT, I have seen a percent scale for one, and it is that way but not near the lower end of the flow range. The lines space out a lot on the scale from about 20% flow to 0%.

Each orifice would have a max flow and the percent scale would read the percent of that minus leakage.
I like the Flow Quik setup. (Audie) It has no orifices to change and no manometers to build or buy. Just blow air through it and the computer records the data.

I just don't know if it is as accurate when atomospheric conditions change day to day. I don't think it uses a sharp edged orifice and don't know what it uses to make it accurate and immune to weather changes like a orifice bench.
David

------------------
Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

[This message has been edited by davidpozzi (edited 03-23-2002).]