FREE TOOL · QUICK ESTIMATE
MAF → HP estimator
Convert your peak MAF reading (g/s) to estimated crank HP. Tuners use this to sanity-check a dyno result against the airflow the engine is actually pulling, or to set a Stage 2 / Stage 3 target.
The math
The classic rule-of-thumb is HP ≈ MAF (g/s) × K where K depends on fuel + thermal efficiency.
| Engine type | K factor | Source |
|---|---|---|
| Petrol NA | 0.55 | Classic 1990s rule-of-thumb (Corky Bell) |
| Petrol turbo | 0.69 | Higher BSFC + intercooler losses |
| Diesel turbo | 0.83 | Higher AFR, much higher BSFC |
Real-world deviation: ±10% depending on intake / intercooler / engine state. Use as a sanity check, not a final figure.