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Turbo Boost Pressure Calculator

Work out turbo boost pressure instantly with clear inputs, formula shown and shareable results.

About Turbo Boost Pressure Calculator

Power scales roughly with the mass of air delivered, so with the pressure ratio. One bar of boost nearly doubles absolute manifold pressure and therefore power, less a correction because compression heats the charge — which is what the intercooler recovers.

Formula

Boost power

pressure ratio = (atmospheric + boost) / atmospheric; power approx NA power x ratio x charge cooling factor

Worked example

With the default values below, Turbo Boost Pressure Calculator returns Estimated boosted power of 216.42. Change any input above and every figure here is recalculated in your browser.

Inputs used

Boost pressure
0.9 bar
Atmospheric pressure
1.013 bar
Naturally aspirated power
120 hp
Intercooler efficiency
75 %

Results

Estimated boosted power
216.42 hp
Pressure ratio
1.89 x
Absolute manifold pressure
1.91 bar
Boost pressure
13.05 psi

Step by step

  1. 1Values used
  2. 2Boost power
  3. 3Estimated boosted power= 216.42 hp
  4. 4Pressure ratio= 1.89 x
  5. 5Absolute manifold pressure= 1.91 bar
  6. 6Boost pressure= 13.05 psi

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does compression heat the air?

Compressing a gas raises its temperature, reducing density and therefore the oxygen mass delivered. An intercooler recovers most of that loss.

Is boost pressure the same as power?

Not quite. Turbine and compressor efficiency, valve timing and fuelling all matter, so two engines at the same boost can differ substantially.

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