flow benches dont flow 28" anyway

turbo2256 - You're right. The Superflow bench we used has a 100% flow of 596 CFM on range 6. We could not develop 28" at that volume. The standard configuration flowed 503 CFM at 20" , the improved configuration flowed 489 CFM at 10". The Superflow manual has a chart to convert these flows into the volume that would be experienced at 28". As you know, this is the common way of comparing flows; "apples to apples".

I was actually more interested in the fact that the improved configuration flowed almost as much as the standard one with half the pressure difference to push the air.

Since pressure drop varies with the square of volume (that's all the Superflow chart does) I can calculate that it would take 79" (2.85 psi) to push 1000 CFM (700+ HP) through the standard configuration. I can also calculate that it would take only 42" (1.51 psi) to push 1000 CFM through the improved configuration.

The difference of 1.34 psi is the measure of improvement that means the most to me, because using that number I can figure out the new operating point for the compressor and system together. That's were the extra 10% HP comes from.

Are you planning to attend the OSO gathering on April 27th at the Tin Fish?

What instruments did you use to measure the velocities across the cooler.

Pitot tube and digital manometer, tools I use in my business. Flow bench guys would call this a velocity probe.

What type of business are you in. I think by your posts we are in a similar line of work

Industrial ventilation, air pollution control systems, HVAC systems, air sampling etc. I have my own consulting company. We do the initial investigations when people are having problems with air quality, then design a solution. The solution is often a better (high performance?!) air handling system. I love being able to apply the same science to high performance engines, boats etc.

What do you do for a living?

Pretty much the same thing!