i like this site...
http://www.injector.com/injectorselection.php as you can change the bsfc rather than using 0.55 fixed
plus it gudies you through everything and gives the formulas
* For naturally aspirated engines, estimate BSFC to be 0.4 to 0.5
* For nitrous engines, estimate BSFC to be 0.5 to 0.6
* For forced induction, estimate BSFC to be 0.6 to 0.7
* For rotary engines, estimate BSFC to be 0.6 to 0.7
* For engines running methanol, double the appropriate gasoline BSFC (e.g. a forced induction methanol engine has a BSFC between 1.2 and 1.4)
that site also allows conversion of various different flow rates...
Dave