NA to Boosted HP Calculator
Estimate horsepower after adding a turbo or supercharger to an NA engine.
Adding a turbocharger or supercharger forces more air into the engine, raising horsepower roughly in proportion to the pressure ratio. This calculator estimates the new power from your naturally aspirated baseline and target boost.
NA to Boosted Formula
The pressure ratio compares total manifold pressure (atmospheric + boost) to atmospheric alone. Real gains fall a little short of the theoretical figure because compressing air heats it, reducing density — which is why intercooling matters.
How to Use This Calculator
- Enter your NA horsepower.
- Enter target boost in PSI.
- Read the estimated boosted horsepower.
Worked Example
Frequently Asked Questions
Roughly in proportion to the pressure ratio: HP × (14.7 + PSI) ÷ 14.7. About 8 PSI can add 40–50% power, minus a small loss to charge heat.
Compressing air heats it, lowering its density. Without effective intercooling, real gains fall a bit short of the pressure-ratio estimate.
Turbos are more efficient and often make more peak power; superchargers give instant response. Both follow the same pressure-ratio physics.
Usually yes — fuelling, often lower compression, and stronger internals at higher boost levels, plus tuning to keep the air-fuel ratio safe.
It depends entirely on the engine, fuel, and build. Low boost (5–8 PSI) is common on stock-ish engines; high boost needs forged internals and careful tuning.