Brush the corn with the olive oil and place on a hot grill. Grill the corn on all sides until all of the sides are charred. (About 6-8 minutes). In a bowl, combine the mayonnaise, crema Mexicana, chili powder, and cotija. Stir until all of the ingredients appear to be well mixed.
Coat all sides of the corn with the mayonnaise mixture. Sprinkle extra Cotija cheese on top and serve with a lime wedge.