Question for the Motor Heads

[Sutts]

Originally Posted by Blakduk

Bliss- unfortunately i live in an area where supercharged hotrods are rare so my opportunities to steal one are very limited. Also i'm a wuss and extremely scared of getting caught. Basically i have to take other people's word for how the real thing works.
Your argument makes sense, it seems plausible but.... i haven't seen the proof.

Basically i've got two engineers telling me different things, and two sims displaying different things (this could turn into another 'plane on a conveyor belt' thread)

If boost rises when rpm falls (at a fixed throttle setting) and boost falls as rpm rises then the sim is correct.

As mentioned earlier, an engine is just like a big suction pump, sucking air fuel mixture out of the inlet manifold and thereby reducing the pressure in that manifold (which shows on the boost gauge).

The higher the RPM (at a fixed throttle setting), the faster the air is pumped out of the manifold and the lower the manifold pressure becomes. On the other hand, when RPMs are reduced (at a fixed throttle setting), less air is being sucked out and the pressure rises.

When the engine isn't running, the suction pump stops and the pressure in the manifold returns to the atmospheric pressure at the current altitude being flown.

On a non-supercharged / non-turbo charged engine, the highest boost pressure available is the atmospheric pressure at the current altitude.
On a supercharged / turbo charged engine, the highest boost pressure available is the max pressure provided by the compressor at the current altitude.

That's my understanding anyway.