In this edition of talking points we will be discussing the installation of an aftermarket off road H-Pipe.
Lets take a minute to talk about safety. In order to change the H-pipe assembly you will need to raise the front of the car off of the ground. You may choose to use ramps or jack stands. Which ever method you choose be sure that the car is supported in a safe manner and that the paring brake is set. It is also recommended to chock the rear tires to keep the car from rolling backwards. Never support the car on a jack only! Serious injury or death could occur if the car falls down with you underneath.
With the car safely raised in the front we can now begin the dis-assembly of the stock H-pipe. First disconnect the battery cables and remove the battery. Next remove the battery tray. You will now have access to the passenger top O2 sensor and its wiring harness. Carefully unplug the harness from the sensor. Now we can move our attention to the underside of the car.
From the underside you will need to locate the passenger rear O2 sensor and unplug the harness. Now locate the rear driver side O2 sensor and unplug it as well. (It is not necessary to unplug the top O2 sensor on the driver side as it is located on the manifold and not the H-pipe assembly)
After you have disconnected the O2 sensors You will now loosen the two rear clamps that hold the back of the H-pipe to the axle back exhaust pipes with a ratchet. Once the bolts are loose you need to locate the small spring tab and lift gently with a flat screwdriver while moving the clamp toward the rear of the car. If done correctly this should not require much effort.
Once the rear is disconnected we can move our attention to the H-pipe to manifold bolts. It may be necessary to use a good penetrating oil in order to loosen these bolts. With a long extension and 11/16 socket remove the two nuts that secure the H-pipe to the manifolds on both sides. Set these nuts aside as they will be used in the installation of the new system.
Once you have all bolts removed you may now slide the factory H-pipe assembly towards the rear of the vehicle and out of the hangers. Take your time here and use a second set of hands if available. Remove the pipe from the underside of the car.
You will now need to transfer the O2 sensors from the factory piece to your new aftermarket unit. Using a 7/8 open end wrench or other suitable tool remove one at a time the O2 sensors and move them over to your new H-pipe. It is a good idea to use a little anti seize compound on the threads before re-installing the O2 sensors into the new pipe.
Once you have transfered all the O2 sensors over you will need to take a moment and connect the two halves of your new H-pipe. Slip the C clamp over the large side of the "H" connection and slip the small pipe into the larger one. Measure the position of the factory pipe from the outside edge of one opening to the center of the other and adjust your new pipe as close to this as possible to ease installation. Tighten loosely the C clamp. Slide the new H-pipe assembly under the car and reverse the disassembly process. Take your time and this should go smooth. You will want to take care in tightening your H-pipe to manifold bolts, taking care to snug them up in an even manner so that you have a square seal on the flange. If you get one side too tight you may develop an exhaust leak. Make sure you tighten all bolts and reconnect all O2 sensors. You may now go back up top and reconnect the top passenger O2 sensor harness and reinstall the battery tray and battery. While the car is still supported in the front start it up and check for leaks. I like to start it and bring it up to normal temperature and then let it cool. Retighten the bolts before driving as they seem to loosen after one or two thermal cycles. Now go enjoy!