BSFC Calculator
Compute BSFC (Brake Specific Fuel Consumption) from dyno HP + fuel flow, or project fuel flow from HP and BSFC.
How to Use
- Pick a direction — dyno-derived BSFC, or project fuel flow from target HP.
- Enter the two knowns and read the third.
Direction
Inputs
Result
Formula
BSFC
BSFC = ṁ_fuel (lb/hr) / HP
Fuel flow
ṁ_fuel = HP · BSFC
HP from fuel
HP = ṁ_fuel / BSFC
Frequently Asked Questions
What is BSFC?
Pounds of fuel burned per hour per horsepower. Low BSFC = efficient engine. Typical: NA gas 0.45-0.50, turbo 0.55-0.65, diesel 0.35-0.42.
Why does BSFC rise under boost?
Rich AFR + retarded timing keep knock at bay. Good tune can keep turbo BSFC near 0.55; lazy tune blows past 0.70.
E85 BSFC higher?
Yes — about 1.4× gas because E85 has 1/3 less energy per lb. But cooling charge + octane can recover some.
Common Use Cases
Dyno analysis
Compute BSFC from fuel flow logs + rwhp.
Build planning
Project fuel flow before spec'ing pump and injectors.
Last updated: