Test Pipe Install
These instructions explain how to remove a catalytic converter for Off-Road use ONLY! These instructions were made while a test pipe was installed on a '92 Dakota, however, can be applied to almost any vehicle! If your car is 1996 or newer, you have OBD-II and need to purchase a downstream O2 sensor mimic.

Step 1: Purchase a length of exhaust pipe that is 4"-6" longer than the converter. Make sure that the inside diameter (ID) of the pipe matches the ID of the larger of the inlet or outlet of the converter. Additionally, you will need 2 stainless steel band clamps of the appropriate size. These are available from NAPA, Summit, etc...

Step 2: Secure Vehicle on jack stands or a vehicle lift so that the converter is easily accessible
Step 3: Measure the straight pipe against the converter so that 2"-4" of pipe are left on each side of the converter. Mark a line around the pipe with a permanent marker/scribe/etc.
Step 4: Cut both ends of the converter off using a cutoff wheel, Saw-Zall, Hack Saw, etc. Try to keep the cut as perpendicular to the pipe as possible.
Step 5: De-bur the ID of the pipe to make sure that none of the metal will block exhaust flow
Step 6: Dry fit the test pipe and clamps to make sure that everything fits.
Step 7: Tighten the clamps down per the instructions that they come with. These clamps seal well, and allow easy test-pipe installation for use at the track. Your EFI computer may require a little time to "learn" since there will be reduced back pressure. Enjoy!