Long and boring, I'm afraid ;o)
I'm trying to understand the purpose of intercoolers on turbo-charged cars. I've done a web search and the basic reason to cool the intake charge seems to be to reduce the possibility of detonation. That seems quite logical, and I'm quite happy with that.
However a lot of the sites talked about reducing the "density" of the intake charge, (since cold air is denser than hot air), thereby increasing power - even the excellent howstuffworks website. I have a big problem with this. As I understand it, the statement that "cold air is denser than hot air" has to be qualified by adding "at the same pressure", and surely the pressure on the inlet side of the intercooler is different than the outlet.
I can understand how on a cold day, more molecules of air are drawn into the engine than on a hot day (because the air is denser), and the engine will have more power.
But I can't see how this argument can be extended to intercoolers. The same number of molecules leave the intercooler as entered it, and surely this depends on the density of the ambient air, not the density of the air leaving the intercooler?
To put it another way:
For the intercooler to increase the mass of air entering the engine, it must increase the mass flow upstream at the air inlet. I just can't see that happening, when you consider all the plumbing in the way (turbo, air mass meter, throttle plate, air filter, etc).
Can someone help!