Engine Displacement to HP Estimator
Estimate theoretical horsepower based on engine displacement (cc/L) and technology type. Useful for comparing naturally aspirated, turbocharged, and high-performance engines.
About
Converting engine displacement to horsepower is not a direct physical conversion like converting meters to feet. Displacement refers to the volume of air swept by the pistons, while horsepower measures the rate of work done. The efficiency of converting that air volume into power depends heavily on engine technology: induction type (Turbo/NA), fuel injection, compression ratio, and redline.
This tool acts as a statistical estimator. It utilizes historical and modern automotive engineering coefficients - expressed as Specific Output (HP/L) - to provide a realistic power range for a given engine size. It is valuable for benchmarking vehicle specs or evaluating the potential of modified engines.
Formulas
The calculation defines a lower and upper bound for power based on the specific output coefficient (k) of the selected engine technology.
Where V is displacement. For inputs in cubic centimeters (cc), the tool first normalizes to liters:
Reference Data
| Engine Technology Era/Type | Specific Output (HP/Liter) | Example (2.0L Engine) |
|---|---|---|
| Classic OHV / Economy (Pre-2000) | 45 − 60 | 90 − 120 HP |
| Modern Economy NA (2000-2015) | 60 − 75 | 120 − 150 HP |
| High-Perf NA (VTEC, GDI) | 85 − 100 | 170 − 200 HP |
| Turbo Diesel (Common Rail) | 80 − 110 | 160 − 220 HP |
| Standard Turbo Petrol | 100 − 130 | 200 − 260 HP |
| Performance Turbo / Race | 150 − 200 | 300 − 400 HP |
| Rotary (Wankel) | 160 − 190 | 210 − 250 HP (1.3L) |