- Doug Thorley Long Tube Headers PN: THY-517-LS-C
- URD Performance Y-Pipe
- URD Rear O2 Sim
- Wicked Flows 18" muffler PN: 18SC300*
- Vibrant Performance Resonator PN: 1142*
- 13mm open end wrench
- 4mm, 6mm, 10mm, 12mm, 14mm socket drives
- Torque wrench 10 to 50 ft lbs
- M12 (?) allen wrench
- Anti-seize compound
- PB Blast (or any penetrating lubricant of your choice)
- 6 M8-1.25 x 30 bolts
- 6 8mm lock washers
- 6 8mm flat washers
- associated hardware included with each kit (retain all hardware for reuse if required)
*Note: Since this guide covers install of the 2012 Doug Thorley Long Tube headers, an additional exhaust manifold obstructs the top three studs on both the left and right hand header manifolds. My work around was to use bolts.
I was originally under the impression that the y-pipe was a single piece, but it sleeves together and gets crush clamped at final install.
The additional hardware I had to pick up. I recommend picking up everything prior to dis-assembly of your vehicle.
I jacked up the front end of my truck and removed the tires for workability in the fender area. It made the install exceptionally easier. After I took off the tires, I used a flat head screwdriver to remove the rock guards pictured. Just a little prying action under the head of the tabs will work them loose. I took my time as to not break the little clips. Inexpensive, but still better to be safe than sorry.
The driver side is pictured, the passenger side is similar. While you are in the wheel well, now is a good time to disconnect the oxygen sensor from each of the catalytic converters. I chose to leave them installed in the Y-pipe for now as removing the y-pipe will make removing the sensors easier and they will be less prone to stripping.
Ignore the deceptive 'Red Square' for now, I'll get to that later. The sensor connector is located where my middle finger is pointing. I don't have a better picture than this, sorry. The passenger side is similar. Those little plastic clips were a pain in the butt to get disconnected. Take your time and slowly wiggle them out. You will be reusing the 02 sensors and you do not want to break any of the wires.
I began the removal process by removing the stock Y-pipe. I removed the rubber bushings holding the y-pipe to the vehicle under-body. A little squirt of PB Blast and some wiggling popped these off easily. Retain these bushings for reuse. Disconnect the two bolts holding the passenger side Y-pipe and discard (or retain for some extra scrounge hardware for future projects). Remove the two forward studs on the passenger side Y-pipe where it connects to the passenger side exhaust collector. You will not be reusing these studs as the supplied hardware is replaced with bolts. Unfortunately, in my haste, I neglected to capture this step with my camera. It should be fairly straight forward.
Work your way to the drivers side of the vehicle and follow the Y-pipe up over a cross-member. On that cross-member is a bracket. I tried my best to theorize its purpose other than to limit movement of the y-pipe. I'm sure a commenter might be able to clarify. I removed it and stored it off the vehicle for safe keeping. Remove the rubber bushing on this side in the same manner as the one previously. On another note, I also removed the silver heat shield from above the stock y-pipe to aid in its removal. I didn't want to damage anything. This was not required as there was allowable clearances and merely resulted in another step to reinstall it upon completion. Fortunately, not pictured for this writeup.
Additionally, not pictured is removing the two studs connecting to the driver side collector. These two studs should be removed in the same manner as the two from the passenger side.
Return to the passenger side of the vehicle and remove the two bolts from the union where the Y-pipe meets the exhaust pipe. I retained these bolts along with the factory crush washer. Pictured as a silver wire-mesh. It is recommended that you replace all crush washers when installing new items as it forms a better seal so I've been told. I did not do this because the following day I went to the exhaust shop to have them weld up my new aft pipe. I gave them the new crush washer for install.
At this time, you should have enough wiggle room to remove the complete y-pipe assembly. Split the passenger side and carefully feed the longer portion over the cross-member. Its not very heavy but it is oddly balanced so potential damage could occur.
Work your way to the base of the passenger side header. Where it connected to the Y-pipe, you will notice a small bracket connecting to the collector and transmission(?). I removed this bracket for ease of install. Unfortunately I do not have a picture of it installed. The following picture shows where it is located from the passenger side, the driver side is similar. After completing the install of the new headers, these brackets did not line up exactly with the new headers so I used some risk management and neglected to reinstall them. I'm sure they serve a purpose other than to get in the way, use your own digression as to whether or not you wish to reinstall them.
Its a small piece of metal no bigger than a business card.
With everything out of the way underneath the vehicle, proceed to start with whatever side you wish. I started in the driver side wheel well. You will need to first disconnect the exhaust manifold pressure tube thingy as pictured. Both the driver and passenger sides have a shim, pay attention to the orientation of the tab as seen in the picture. I'm not 100% positive if the orientation makes a difference here, but again if you take something off, better put it back the same way you found it (most of the time, heh). I removed the studs pictured, as they will be replaced with bolts found in the DTLT hardware bag. See step one's second picture for the red square
The arrow points to that tab orientation, the drivers side tab is on the bottom.
Step Six and a half:
Forgot important step here, oops. Carefully remove the 02 sensors from the old headers and install them in the location of your choosing on the new headers. You are given a total of four choices, two higher up on the headers (the wires weren't long enough to reach this location for me) or the alternative is two on the y-pipe. I chose the y-pipe location as this worked better for me when routing URD's rear O2 sim. Bear in mind that whatever hole you use, be sure to install the closeout bung in the empty hole.
The most important step and I don't have pictures sadly. Your going to need child hands to get at the 6 nuts holding the header flange to the block or just a lot of time. Remove the 6 nuts from the drivers side and pull the header toward you (if you are working in the wheel well). I had to remove a good majority of the studs to get enough wiggle room to get the header free. Use the 4mm socket to do this, I tried to reach with a box head wrench but the studs aren't really designed for that. I managed to strip one using the wrench then switched to the socket. Lucky for me, I was going to replace the studs on the top row. Whew. If the studs are giving you issues, hit them with a little PB blast and let them sit for a bit. Caution: Be mindful of the seals, your going to want to retain these seals for reuse so take care not to damage them. Your also going to want to reinstall the seals in the same manner in which you removed them, so be observant.
Once you get the stock heads out of the way, I fished in the DTLT headers up from below. Easiest route in my opinion. Use a buddy to align the metal header seal on one stud. Since I had 5 out of 6 studs removed at this time, it was fairly easy to get the new headers on. Feed in the remaining two studs on the bottom row and get nuts started. Note: for all the hardware you remove from the block, dab a light coat of anti-seize on the threads. It will take some movement to get the bolts started. I laced the bolts with a small dab of anti-seize followed by one lock washer then one flat washer. Your going to want to torque these bolts and nuts to 16 ft pounds. Good luck with that. ** Tighten down the driver side then move to passenger side and repeat.
After both sides are wrenched down and tight, you've just completed the hardest part of this install. Now you get to put everything back together. YAY!
**Note: I chose to wrench these down fairly tight, after about 30 to 50 miles I went back and rechecked these bolts and nuts to ensure that they were still tight. Fitting in a torque wrench in that area is a pain. I am in no way condoning my method, always always always ensure the correct torque values.
Don't forget to reconnect those little exhaust ports as depicted in step six. I tightened those down snug.
Work backward from underneath the vehicle, feed the URD y-pipe over the cross-member and loosely install the new crush washer and bolts connecting the collector manifold to the y-pipe at this time. You will come back and tighten these down shortly. Reinstall the rubber bushing that you removed in step two. They should easily slide back on. Slip in the passenger section of the URD y-pipe and attach those two bolts and new crush washer to the header collector as well. Leave them loose at this time. Align the aft bolts up with the rear section of exhaust. Note: Like I stated previously, I used the original crush washer here because my specific application called for it, if you are ending your install here be sure to install the new crush washer in its place.
Now all 6 bolts should be temp installed at this time, four coming off the header manifolds and the two at the base of the y-pipe. Double check that the crush washers didn't move and torque the bolts at the collectors to 46 foot pounds. Once these are torqued down, tighten down the retention bolts on the aft exhaust pipe.
The passenger side of the y-pipe will have a slip union. Snatch up that pipe clamp and wrench that sucker down ensuring that your overlapping both sections of pipe. See picture. I positioned my pipe clamp off to the side which allowed me to wrench down on it and reduces any possibility of stuff getting stuck on the clamp. Call it paranoia if you must.
Everything should be put back together at this time, reinstall the rock guards in your fender well's and reinstall your tires if you took them off. Pat yourself on the back because your all done.
Here are some photos of my final post welded exhaust.
I chose to dump it after the axle, and I'm enjoying the sound. I've put on about 1k miles since the install and its not overly rice'y sounding. The tone is subtle and strict. I'm glad I purchased the resonator, I don't hear rasp at all.
Well I hope this was informative, Ill monitor this post and update with corrections and clarifications as required. If you want another perspective on a header install, check out http://www.xr-underground.com/forum/...ead.php?t=5553 Its not for the 2012+ but it may answer some questions you might have.