FASS (DMAX-7001) Duramax Flow Enhancer Fuel Pump Fass has introduced the Fass D-MAX 7001 Dura-Max Flow Enhancer to solve the low fuel pressure problems on the 6.6L Duramax D-MAX 7001 Dura-Max Flow Enhancer is capable of flowing up to 70 gallons per hour at 10 PSI By installing the Fass DMAX-7001 Dura-Max Flow Enhancer you will dramatically reduce the fuel supply strain placed upon your injection pump