All Tools
Injector Sizing
Bigger power needs bigger fuel. Get the injector size your build actually requires — with real duty-cycle headroom, not marketing numbers.
BSFC in use: 0.6 lb/hp·hr
50 lb/hr
Required injector (80% duty)
525 cc/min
Same size, metric
240 lb/hr
Total fuel flow
419 hp
Existing injectors support
Sizing logic: total flow = hp × BSFC; per injector = total ÷ 6, then ÷ duty limit. cc/min assumes the usual 1 lb/hr ≈ 10.5 cc/min gasoline convention.
Raising base fuel pressure ~40% up increases flow ~18% (square-root rule) — a stop-gap, not a substitute for correctly sized injectors.
Good to know
- BSFC (brake-specific fuel consumption) is fuel burned per horsepower per hour — richer mixtures and E85 push it higher.
- Never size to 100% duty: injectors run hot and lose control past ~85%. 80% is the safe working target.
- E85 needs roughly 30% more flow than petrol for the same power — the presets handle that in the fuel flow, but flow-check your pump too.
- cc/min ratings assume gasoline density; check the manufacturer’s data for your exact part number and pressure.