Re: S4 turbo pressure measurement

[Glenn Lawton <lawtonglenn@gsmai.com>]

Morten Astrup Steen wrote: 
> ...turbopressure...0.5 at idle. approx. 0.9-1.2 at normal driving and 
> when really hitting it I've seen 1.7-1.8 once or twice.
> 
> I thought it should be 1.0 at idle (atm. pressure)...


Nope.

It's 1.0 when the engine is off, but as soon as the engine starts
it creates a partial vacuum (therefore less than 1.0atm) in the
intake manifold. It is this partial vacuum that draws the air
in through the airbox.

All normally aspirated engines live their life less than 1.0.

Glenn