Altitude and atmospheric pressure

[dmp0001]

Altitude and atmospheric pressure
-1000 1.0296
0 1.0000
1000 0.9711
2000 0.9428
3000 0.9151
4000 0.8881
5000 0.8617
6000 0.8359
7000 0.8107
8000 0.7861
Ok, so this is a list of the effects of altitude on atmospheric pressures. What this means is actual compression ratios of your engine. So, at 6000 feet I will have an actual compression ratio of 8.3:1 (sad). This leads me to a simple question. Does my fuel injection attempt to compensate for this by pulling in more air and fuel? I have also considered the possibility that running lower octane gasoline would create more power without ping. Does anyone have any expertise or incite on this subject?

 

[Cataract2]

Fuel injection will compensate for the change in altitude. I was stationed in Colorado Springs (el: 6000 ft.) and both my 05 XB9SX and 08 1125R adjusted to it. Did lose some power, but I gained a bit in gas millage.

 

[Livers]

So, at 6000 feet I will have an actual compression ratio of 8.3:1 (sad).

What? The compression ratio is mechanical. How can it change?

 

[fireinxb]

Static vs dynamic compression ratios.

 

[konarider94]

it kills your volumetric efficiency. because you are getting less air the ecm reduces the pulse width of the fuel injection to maintain the correct air fuel ratio. this is why you get better fuel economy and less power.