Related Photo Galleries
Simple math determined the injector size. Desired HP × Brake Specific Fuel Consumption (typically .500 to .550 for pump gas) / number of cylinders = pounds of fuel used per hour. This is then usually divided by a normally recommended maximum duty cycle of 80 percent, or 0.8 to get the injector you need. In Bischoff's case it, was 700 × .45 (very efficient) / 8 = 39 lb/hr, and we see that at that rate he was at 86 percent duty cycle.