Altitude Compensation

[David M Parrish]

> From:          "Robert J. Harris" <bob at bobthecomputerguy.com>

> Does anyone do any altitude compensation?  Because, as altitude
> increases, not only does the air mass density decrease, but the
> percentage of oxygen decreases (simple physics - check books
> before questioning or flaming) and the oxygen decrease is independent
> of the density decrease.  

Okay. I'll bite. What's your source for this simple physics? 
(Remember Brownian motion and diffusion.)

On cars with MAF sensors, it's automatic, since you're measuring 
the Mass of air and X mass of air needs Y mass of fuel.

Speed density systems measure pressure and temperature to calculate 
the mass.

---
David Parrish
Carbs and aircraft injection are a whole 'nuther ballpark.