Posted by Desoto61 [138.162.0.43] on Thursday, April 23, 2015 at 06:30:36 :
In Reply to: Re: Interesting, but useless posted by Don in Missouri [97.64.167.2] on Wednesday, April 22, 2015 at 17:48:06 :
In a fuel injected vehicle the O2 sensor is always trying to help the computer maintain a mostly stoichiometric mixture (sort of due to the catalytic converter but that's another discussion), so ideally with or without the turbo there is only enough gas added to burn completely. The reality isn't so ideal, hence the catalyst. Extra oxygen only helps to a point, then you start to run lean and damage things.
Most of the benefit comes from the other two factors. More air/fuel = higher effective compression & more combustion/expansion = more power.
It can also provide other interesting benefits if the engine is built around being boosted.