How does ambient air temperature effect boost pressure? Does cold air make boost pressure go up or go down? So far, I am of the opinion that cold air makes boost pressure go down because cold air, although more dense, has less pressure.
For example, if you have two cans with pressure gauges on them. Fill both cans with the same mass of air. Now heat one can on a stove, and cool the other can in a freezer. The heated can will show a higher pressure reading on its gauge than the cooled can. This means that cold air has less pressure than hot air. Therefore, since cold air has less pressure than hot air, you should see less boost in cold weather than you would in warm weather on a compressor that has a fixed rpm that it runs at (like a belt driven supercharger).
Although you should see less boost in the cold weather, the power of the engine increases because the air is more dense and therefore there is more mass of air in the engine's cylinders.
The bottom line here is that it appears that a supercharger with a fixed compressor speed will produce less boost pressure in cold weather than it will in warm weather simply because cold air, although more dense, has less pressure. However, the fact that the cold air is more dense, even though it has less pressure, means that an engine will produce more power in cold air.
Anyone have any opinions on this? What effect does cold ambient air or hot ambient air have on boost pressure from a compressor that runs at a fixed speed such as a belt driven supercharger?