Redeye

The problem with water/air intercoolers is that they stop cooling the air once the water temp reaches a certain point. You could use some type of radiator for it, but then you are right back where you started. The water/air intercooler was originally designed (if I remember correctly) for drag racers that could dump a bunch of ice water in there and cool the air below ambient temp... and it works great for this because you can change the water or add ice after every run. On a track or street car this is not possible or too much of a PITA (imagine stopping at every gas station to buy a bag of ice or having to pit every other lap to recharge the IC).

Just my $0.02

Sami951

The way I see it is a water/air intercooler is more efficient; in a normal scenario both a water/air and an air/air intercooler are working with ambient temperature, but since water conducts heat a lot better than air, you can get something like (just guessing!) 90% efficiency instead of say 70% ... yes, you will need a radiator for the water/air intercooler, and also a reservoir, plumbing and a water pump, but you should end up with cooler intake air.

The idea is that if you have enough water, the temperature won't rise significantly over relatively short periods of high boost driving, and it'll get to cool down again when you're not on boost. So for street driving it should be very good, on a track it should still be better than a air/air cooler, and on a top speed record run it'll perform about the same.

Air/air intercoolers on the other hand are dead reliable and inexpensive compared to water/air solutions, so they do make a lot of sense.

Then again if you're drag racing and use ice water, you should be able to get more than 100% efficiency, which will never happen with air/air