turbo question

[Showgood1]

Can someone explain to me how staged and dual turbo's work? I savey one turbo and how a wastegate works (I think). But what is the advantage of two?

[rjschoolcraft]

Staged, or in-series, turbos simply increase the pressure ratio capability. Typical compressors for turbochargers are capable of up to about 3.5:1 max. Put two in series, you get 7:1. At sea level, that goes from max boost capability of about 37 psi to about 88 psi.

Twin turbos (one for each bank of a V-8, for instance) do the same job as one big one. They offer package advantages and, to some extent, performance advantages. Two smaller turbos will spool quicker (less rotating inertia) than one larger one.