PTS Flowbench Forum

The delta P is the actual pressure the inclined manometer is measuring. If all you're using the inclined manometer for is the percentage scale, you don't need the delta P at all but, having it gives you the option of comparing your inclined's reading to other manometers and also it gives you numbers plug back into the other sections of the spreadsheet.

Ok, that makes sense. Kind of what I thought but wasn't positive that's what was going on. I am just happy that it works now!!!

Ok, another question. We tried to test a head yesterday and the flow seems way high for a stock SBC head. Was showing around 200 cfm. If there is no baffle under the orifice plate will the readings not be correct?

Currently there is only a baffle above the orifice plate. Just trying to understand why the baffle would change the pressure differential????

On the intake flow the baffle below the orifice is not needed, that said how did you calibrate? and what are you using for a bore adapter?

Rick

Ok, that makes sense.

Bench was calibrated with Bruce's plates. So a 250cfm @ 16" plate internal and then a 250cfm @ 28" plate on top of the bench. It seemed that both manometer's were reading correctly at that time.

The head adapter we made. 4" bore about 4" long. I used my CNC plasma cutter and cut the top plate out of 3/16" steel and cut a bottom plate to bolt to the bench. Then welded a 4" piece of tubing between them.

We used the head gasket to seal the head to the adapter and actually bolted it down.

The stock head seemed high at 200cfm. However the ported head (not by us) was at 223cfm which is inline with what I can find for a ported stock sbc head.

Thanks again.

Depends on what SBC you are testing. I have tested many SBC heads with the 1.94 intakes and 2.02 intakes that do flow 200 cfm plus or minus a little. I had a set of the 441 casting open chamber heads with 1.94 that flowed 207 cfm stock.

John

Gotcha. They are #462 double hump heads. Just received some other feedback that 200cfm in stock form is not out of the question for those heads. I feel much better about the results now.

Thanks everyone.