Wheezin

[PDQSHIP@aol.com]

In a message dated 96-03-18 13:19:44 EST, you write:

>
>Y'all are forgetting/neglecting a pretty basic principle.  A turbocharger 
>is DRIVEN by exhaust gasses.  The compressor's job is to get more MASS 
>into the combustion chamber, which is compressed, combusted, and then 
>dumped into the exhaust stream.  If you start with a lower ambient 
>pressure (lower atmospheric pressure), the inlet air is necessarily LESS 
>DENSE than at higher atmospheric pressures.  Less dense air means less 
>mass of air (specifically for a given velocity).  Less mass coming out of 
>the cylinder will result in less mass to push the turbine side (exhaust 
>side) of the turbo.  Result - the turbo will spin more slowly and 
>compress less than at higher atmospheric pressures.  Find a textbook and 
>look at a P-v diagram for an internal combustion engine.  
>
>Imagine having a propeller of some sort (maybe one of those colorful foil 
>things on a stick like you'd get at the fair or something).  Blowing on it 
>will not spin it as fast as spraying it with a water hose.  The water is 
>more dense and has more kinetic energy (1/2 MV^2) than the air.  Well 
>substitute less mass for M in that equation and you'll see the effect of 
>high altitude on the system.
>
>Jerem

Good thinkin here....  What happens before the turbine has every effect on
what happens TO the turbine....  What happens after the turbine really isn't
a function of changes in P from altitude...  Not so sure that the high
altitude function couldn't be solved on the cold side tho.......Lots of air
movement doesn't necessarily mean it has to be done with speed....   + Speed
of a compressor = + heat of compressed air = reduction in density of air = +
speed of compressor 2

Scott