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Originally Posted by jeff4598
Nice discussion about how much AIR the engine gets at altitude but engines don't burn fuel with air they use O2-I think it's all about the lower concentration of O2 in the same amount of air that produces less power at altitude.Alot like people but cars cant make or use extra red blood cells  |
Air density is one very important factor in arriving at oxygen content of the intake charge. At 5400 ft above sea level, every component of air is reduced per cubic meter of volume, not just oxygen.
It's useful to talk about air and fuel because the oxygen can come from two sources, the air and the fuel. This is one reason I'm going to try the E85 mix (much higher oxygen content than 100% petroleum-based gasoline), because there's oxygen in E85 fuel to make up for the lower oxygen content in the intake air. Without FI and/or the ability to change the AFR (notice they say "air" fuel ratio because the oxygen content is outside the control of the ECU, it can only change volumes not content) I can only work with the fuel side of the mixture.
Anyway, the use of the term "air" is intentional. It's the component we're controlling. The objective is indeed to get oxygen into the engine, but we accomplish that by working with the both the air and fuel.
Dave