Injector Size Calculator Use this Injector calculator to correctly size your Injectors vs your Horsepower Goal. **Also makes a great “Dyno Sheet” Lie Detector!** When buying injectors keep an 80% Injector Duty Cycle limit. 90% IDC is considerd the Maximum Safe Limit. If your IDC is more than 90% your Injectors are too small! # of Cylinders Fuel Pressure (psi) Injector full flow value (size) in CC/Min Engine Aspiration Naturally AspiratedSuperchargedTurbocharged Duty Cycle 80%85%90%95%100% Fuel Used GasolineE85 Horsepower supported @ crankshaft: Horsepower supported @ wheels: 2018-01-18