Thats a good question, but the gasses exit the IC, hit the wye and are very turbulent so I feel confident that the air will be a well mixed blend of left and right air, if you allow me to 'color' the temps in this manner. There are 15 CORES with like 25 holes for the water, I feel that the mixture will not show a measurable gradient, remember the velocity that this stuff is moving, its a hurricane in there. Enjoy, WOody