Turbo Size Calculator
Calculate optimal turbocharger size for your naturally aspirated petrol engine
Calculate Turbo Size
Displacement of your naturally aspirated petrol engine
Target horsepower after turbocharging
Turbo Size Results
Recommended Turbo
Power Analysis
Recommendation
Race-oriented turbo requiring substantial engine modifications.
Important: This calculator is for naturally aspirated petrol engines only. Results are based on Garrett turbocharger guidelines and industry standards.
Note: Turbo sizing requires additional considerations including engine internals, fuel system, and cooling capacity.
Engine Modification Requirements
Example Calculation
BMW E36 M3 Example
Engine: 2.5L (2494cc) S50 naturally aspirated
Stock Power: ~240 HP
Target Power: 500 HP
Power/Liter: 200 HP/L
Calculated Results
Recommended Turbo Size: 48mm
Suggested Model: GT3071R or GT3076R
Estimated Boost: 17.6 PSI
Power Gain: +260 HP
How Turbocharging Works
Exhaust Gases
Engine exhaust spins the turbine wheel
Compressor
Turbine drives compressor wheel via shaft
Boost Pressure
Compressed air increases engine power
Turbo Selection Tips
Smaller turbos spool faster but limit top-end power
Larger turbos provide more power but increase lag
Consider your intended use: daily driving vs racing
Always upgrade supporting systems (fuel, cooling)
Understanding Turbo Sizing
What is Turbo Size?
Turbo size refers to the compressor inducer diameter, measured in millimeters. This measurement determines the airflow capacity and power potential of the turbocharger. Our calculator uses industry-standard Garrett guidelines to recommend optimal sizing.
Size Considerations
- •25-35mm: Small turbos for daily driving (quick spool)
- •35-48mm: Medium turbos for street/track (balanced)
- •48-65mm: Large turbos for racing (maximum power)
- •65mm+: Extreme applications (professional builds)
Required Modifications
Essential Upgrades
- • Engine management (ECU tune)
- • Fuel system upgrade (injectors, pump)
- • Intercooler and piping
- • Exhaust manifold and downpipe
- • Oil feed and return lines
High Power Builds
- • Forged pistons and connecting rods
- • Upgraded head gasket and bolts
- • Larger capacity oil pump
- • Enhanced cooling system
- • Strengthened transmission