MACAUBET77 Any CART racing team has a rather interesting relationship with its engine manufacturer. Each day of practice, qualifying and racing, CART officials pass out the pop-off valves to the teams and collect them in the evening. To keep the playing field even (and the manifold pressures within the rules), CART provides each team with a manifold pressure relief, or pop-off valve, to put on top of their intake manifold. When the turbo over-pressurizes things, a pop-off valve releases the extra pressure.|Power Tools are used in Industry