Boost Pressure → HP Estimator
Estimate the power a given boost level adds to your engine.
Get a safe, dyno-proven boost tune?
How it works
Forced induction multiplies the air (and fuel) the engine gets. The pressure ratio — absolute manifold pressure divided by atmospheric (14.7 psi) — tells you roughly how much more air, and therefore power, you’re making. This calculator applies that ratio to your naturally-aspirated power and knocks off a little for real-world losses (heat, backpressure, intercooler drop).
The efficiency factor (default 90%) accounts for the fact that a real turbo system never delivers the full theoretical gain — intake air heats up, exhaust backpressure rises, and the intercooler isn’t perfect. Better setups get closer to 95%; hot, restrictive ones drop to 80%.
This is an estimate to set expectations. Actual power depends on the turbo, fuel, timing and calibration. The reliable number comes off the dyno — which is where every DMS boost figure is proven.
These figures are engineering guidelines to help you plan. The reliable number always comes off the dyno — that's how every DMS build is proven.
FAQ
Is “x hp per psi” a real rule?
Only loosely — power scales with the pressure RATIO, not psi directly, so the first few psi add more than the last few. The pressure-ratio method here is far more accurate than a flat “hp per psi”.
Why isn’t the gain 100% of the pressure ratio?
Real systems lose power to intake heat, exhaust backpressure and intercooler pressure drop. The efficiency factor models that — 90% is a sensible default.
Can I just run more boost for more power?
Up to the limits of your fuelling, internals and the turbo’s efficient range — beyond that you make heat and risk the engine. We tune to the safe maximum, not the highest number.