Flowbench calibration problems

[91daytona]

My PTS flowbench has been sitting unused for a couple of months as the race season has been keeping me busy. Today I fired it up and rechecked the intake calibration with one of Bruce's 300@28 plates and the computer shows 297-299 great. I was suspecting an issue with the exhaust numbers as my heads always seemed a little low. With Bruce's 300 plate I am reading 270cfm. I then tried one of Bruce's 200@28 plates and I am showing 181cfm. I checked all the small issues like leaks,new mouse homes and found no problems. I honestly never checked calibration on the exhaust side but have always suspected low numbers. When I attended Darrin Morgans class on head porting he preached air speed on the exhaust side was more important than flow numbers but customers still want good numbers. Do you guys have any ideas on what my problem could be. I don't want to calibrate the exhaust side and mess up my intake numbers. Thanks for any help. John

[Brucepts]

Assume u are testing exhaust?

Did you flip the plates?

[Brucepts]

Have to also calibrate in exhaust mode, you will have two different Cd's one for intake an done for exhaust

[91daytona]

I did flip both plates but I never calibrated the bench in the exhaust mode. I will try that tomorrow if these old brain cells still remember how. Thanks Bruce. Building this bench is the best thing I've ever done. To let it sit for 3 months and the calibration is exactly where I set it is hard to believe.

[91daytona]

Thanks for pointing me in the right direction Bruce. Made the calibration adjustments you told me to make and shes working GREAT. Thanks again.

[Brucepts]

Glad the call clarified it for you