PRESSURE DROP CALCULATION ON MFR

DEAR ALL

PLEASE TELL ME HOW TO CALCULATE PRESSURE DROP THROUGH A MFR FIVEN BY FLS IN A CB COOLER.

THE MFRs HAVE DIFFERENT IDLE HOLE SIZES.

I WANT TO REDUCE THE PRESSURE DROP ON FAN BY INCREASING THE DIAMETER OF THE IDLE HOLE SIZE BUT I DO NOT KNOW HOW MUCH WILL BE THE IMPACT ON THE PRESSURE DROP IF I INCRASE THE DIAMETER OF THE HOLE

SIDHANT