Boost levels

Robert Deis rdeis at
Thu May 3 14:03:38 EDT 2001

On Thu, 3 May 2001, Scott wrote:
> Essentially the turbo is adding an additional %40 air to the cylinder. To 
> get 1.4 bar at altitude you would need to add %65 more air to the cylinder.
> This would require the turbo working %63 harder.
> That could very well be overspeed.

Sure it could- and that's why most boost control systems work based on
gauge pressure, not absolute pressure.

But it's been advertised that Audi systems work on absolute pressure-
meaning that 1.4 bar is what you get be it sea level ot 14000 feet.  Is
this true or not?

  Rob Deis                  "Let the people know beforehand what the law
  MiB3347                      is and what they are to expect." 
  rdeis at                              -- 18th Congress, Rec. 75

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