Injector size calculator
Size injectors for a power goal, or find the max HP your injectors support.
Estimate only. E85 needs ~30% more fuel volume; keep injector duty under ~85% and verify fueling with a wideband before boost.
How injector sizing works
Required injector flow ≈ (target HP × BSFC) ÷ (number of injectors × max duty cycle). BSFC (brake specific fuel consumption) is roughly 0.50 for naturally aspirated gas, ~0.60 boosted, and higher on E85 because ethanol needs ~30% more fuel by volume. Keep max duty under ~85% so you have headroom at the top of the pull — running injectors to 100% leans you out exactly when you can least afford it.
cc/min ≈ lb/hr × 10.5 for gasoline. This is a planning estimate; your real number depends on fuel pressure, BSFC, and the engine. Always verify injector duty and delivered AFR with a wideband in a datalog.