Your biggest problem may be the water tank for the device. Similar devices are marketed to motorhomers, although instead of cooling the air, they drizzle a stream of water in front of the radiator (coming from the motorhomes watertanks) in order to cool the radiator on steep grades.

I think those old canvas bags you see hanging in front of radiators on cars crossing the desert in the 1930's did the same thing. Perhaps you could hang a canvas bag full of water just in front of the air intake.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13