Atmospheric pressure

Hi Jose.
It is difficult to calculate exactly that power is lost in an engine in relation to the height in which it works. As the height increases the air loses density due to temperature, at a lower density the amount of air that enters the cylinder is lower, it has been calculated that an engine loses 10% of its power per 1,000 meters of altitude, with the new gas emission control systems this does not happen because they regulate the work adjustments to correct this problem. I hope I could help. Luck.
Miguel

I understand that the emission control enters to carve when the engine is already in operation and not when only measuring compression ... but I am always with the doubt if the compression varies at sea compared to 4000 meters above sea

The measure must be done in the laboratory to determine there is no exact fact, so I have understood the only difference is the density of the air and its volume porsemage costs more to fill if there is a difference in the seem of being of about 2 percent no more, but there are no written data on it only speculation, sorry for not being able to help you more search in the laboratory database must in the same way to men and machines.

Hi Jose.
Kikemec has given you the exact answer, it is difficult for a fact that can be considered real. I have also discovered that the parameters to measure are not unified, I attach a table that could help you a bit:
rt - ºC P - bar Pr - bar Pt - bar
12 665 27 25 to 27 20
14 700 33 28 to 30 23
16
731 40 30 to 34 25 18
759 46 34 to 39 28 20 786 54 39 to 44
31 22 810 60 44 to
50
35
T = Compression temperature in ºC
P = Compression pressure in bars
PR = Real compression pressure
PT = Total Pressure Admissible Limit
The intake air temperature should be minimal at 20ºC and just like kikemec, I regret not being able to help you better. Luck.
Miguel

Sorry Servilimit friend is a bit confused your table that you show me could specify better. I will be grateful