Creating and installing a crossover pipe or "X-pipe", for your car's exhaust system can help reduce the the operating sound level of your car by routing exhaust gasses more efficiently out of the car. The crossover pipe is shaped like an "X" and will be positioned either behind the catalytic converters in your exhaust system or in front of them. Creating your own crossover pipe will require metal tubing that matches the diameter of your factory exhaust system, as well as access to welding tools.
Measure the distance between the two exhaust pipes that you will be crossing over with the X-pipe. This will determine the maximum width of your X-pipe once it's fully assembled.
Measure the length of the ends of the two pipes that you will be connecting to determine the maximum length of the X-pipe that you'll be welding.
Divide the measurements you've taken by two so that you have four sets of measurements. Ultimately, you will be welding together four small pieces of exhaust tubing to create the "X" shape that gives a crossover pipe its name.
Cut the exhaust tubing into four pieces according to the lengths and widths you've obtained in Step 3.
Weld the exhaust piping together to create an "X" shape and test fit it to the ends of the exhaust pipes that you wish to cross over.
Weld the X-pipe to the ends of your exhaust piping to form the connection. You can now connect the muffler assembly, if there is one in your exhaust system, to the other end of the X-pipe.
