Headers Installation
 

I decided to document my headers installation on my 2006 Tahoe, maybe it'll help someone else. I installed new Pacesetter long tube headers and off road Y-pipe (ORY). The installation process should be fairly similar for other brand headers and other year trucks.

1. Drove the front tires up onto Rhino ramps and then jacked the Tahoe up a little more on the suspension for extra height and placed jack stands under the frame for safety.

2. Disconnected the O2 sensors (4 total). Follow the wire up to a connector, pull the pin and lift the clip to disconnect. I waited until the Y pipe was off the truck before I removed the actual sensors since that appeared to be easier.

3. Removed the spark plug wires. This actually turned out to be a pain in the hinny. They all seemed to be stuck. I ended up destroying two of them (pulled the end connectors off). Good thing I have a slightly used set of MSD plug wires.

4. Removed the oil dipstick tube. It's held on by one 15mm bolt and then you carefully work the tube out. There is an o-ring on the block side of the tube. I inspected it and cleaned it. As long as it's in good condition it should be reusable.

5. The rear nuts on the Y pipe to catback flange came off easily (I had sprayed penetrating oil onto all the Y pipe studs the day before). The front Y pipe to manifold nuts appeared to be rusted solid. It's hard to get at these studs due to the cats being in the way. As per various people's advice, I fired up the Sawzall and cut the Y pipe in three places instead of fighting the frozen front nuts.

6. Unbolted and removed the exhaust manifolds. There are six 13mm bolts on each side. The passenger side is pretty easy. The driver side, not so much. I had to move some wire looms and lines out of the way. The rear bolt on the driver manifold is a hassle, not much room for a rachet.

7. I ended up installing both of the headers from underneath (I've heard you can feed the passenger side down from the top). I bought new GM MLS manifold gaskets, but supposedly you can reuse the old gaskets if they are undamaged. You will need an extra pair of hands at this point. I enlisted the aide of my wife until the headers were in place. The passenger side went in fairly easily (note: do not bolt the passenger side up until the Y pipe is installed, I used a couple of bungie cords to hold the header up temporarily). Since my truck doesn't have an EGR, I used the provided block-off plate. The driver side was a little more difficult to snake into place. I had to remove the driver side spark plugs and corner heatshield to give me more room. It's a tight squeeze to get past the steering shaft, but it can be manuevered and jiggled plus it helps if you use the right cuss words. I left the driver side header bolts loose so I could do some shifting around for optimal clearance later and to help with the ORY install.

8. Now install the Y pipe (I used the Pacesetter Off Road Y-pipe or ORY). You should have left the driver side header loosely bolted and the passenger side header in place, but unbolted. Once the three pieces of the ORY are assembled, leave them unclamped for now. Bolt the passenger header onto the head and as you snug it up, make sure clearance is okay. I had a transmission cooling line that needed to be bent away from the header. Now snug up the driver side header and check for clearance. It was really close to the steering shaft. I had to move a wire on the driver side that touched the header. Torque the header bolts to 18 ft/lbs. I started in the middle and worked my way progressively out towards both ends. Go over the bolts a second time to make sure they are all torqued correctly.

9. Tighten the ORY to catback flange nuts and clamp the ORY in three places. Pacesetter includes regular old fashion muffler clamps, but it's better to invest in good quality exhaust band clamps instead.

10. Install the O2 sensors. The Pacesetter headers and ORY only have two O2 sensor bungs. The rear ones are left off due to lack of cats. So, unless you have high flow cats or bungs for the rear O2 sensors, leave them off. They will have to be tuned out.

11. Reinstall the driver side spark plugs. Install plug wires. Put all the wiring loom and hoses back to their proper place. Reinstall the oil dipstick tube.

12. A tune is now needed. The headers will mess up the fueling requirements and you'll need a tune to take full advantage of your performance potential. Your tuner will also need to remove the rear O2 sensors, so they won't throw a "check engine light" code.

https://www.performancetrucks.net/fo...1&d=1335051816