It's a common mod with many diesel racers. You spray the intercooler with CO2 to reduce the charge air temp.
It's not a good "bang-4-D-buck" mod, but it does work. A 500rwhp setup will gain about 20rwhp with a huge shot of CO2 across the bow. Make sure your air inlet cannot be "fouled" by the CO2, or you'll lose all your gains and then some. I don't run it, but friends do.