All Tools
Boost & Airflow Estimator
Horsepower is air. Enter a target and your engine’s vitals to get the airflow, pressure ratio and boost pressure your turbo needs to supply — then pick a compressor that can actually do it.
L
%
°C
°C
Air mass flow
47.2 lb/min
357 g/s
Boost needed
28 psi
1.93 bar · gauge
Pressure ratio
2.92 : 1
294 kPa absolute
Engine demand
235 cfm
3.22 kg/m³ charge
Turbo class: Large single (GTX3584RS / 6266 class) — pick from a real compressor map at 2.92 PR and 47 lb/min, not just the marketing number.
Assumes the whole engine makes this flow at peak power. Tropical reality check: at 30 °C the ambient air is only ~1.16 kg/m³ — every degree you knock out of the charge with a better intercooler (or water/meth) buys boost headroom. Knocking 15 °C off the charge temp is roughly like finding 0.1–0.15 PR of free compressor work.
Good to know
- Airflow = power × BSFC × AFR. The estimator assumes the engine makes its full flow at peak power — drive the turbo using the pressure ratio and lb/min numbers on a real compressor map.
- Pressure ratio is absolute manifold pressure ÷ ambient. 1 bar of “boost” is PR 2.0 at sea level; at 1,000 m the same PR needs a slightly bigger pressure delta.
- Post-intercooler charge temperature matters more than people think: a 10 °C hotter charge needs ~3% more pressure to carry the same air mass.
- These are demand numbers for sizing — real-world boost typically lands a little higher once compressor and intercooler efficiency are accounted for.