The modern internal combustion engine is, first and foremost, a pump. It pumps in an air/fuel mixture, and it pumps out power, heat, and combustion byproducts. If you want to improve the efficiency of any pump, one method is to remove any restrictions placed on intake or output. When it comes to most engines, that means intake and exhaust. Since we’ve already covered the Tundra Exhaust System, we’ll focus now on the intake system.