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Discussion Starter #1 (Edited)
I installed an X-pipe on my G8 last week and took a few pictures along the way for anyone wanting to do this themselves. The shop I went to quoted me $150 for labor if I had all of my own parts to have it welded up, so instead I bought clamps and put the whole thing together to have it welded up later on. I expected to hear a few leaks in the system with the clamped setup but all good so far; I may not even have it welded unless it starts leaking. Your list of parts may vary, but this is what I did.

Parts needed:
2 - 18" long, 2.25" pipes - local parts store
2 - 24" long, 2.25" pipes - local parts store
1 - 2.25" X-Pipe - Amazon.com
8 - 2.25" muffler clamps - local parts store
1 - Tailpipe cutter - Rented from local parts store
1 - Tailpipe expander - Rented from local parts store

First off, my car is a 2009.1, so it doesn't have the secondary pup cats. If your car does have them then you'll need a longer section of pipes to make up which there is already a thread on.

I started by cutting the entire mid-muffler and resonators out, leaving as much stock pipe as possible in front of the mid muffler since there's little room between it and the bends up to the pre-cats and cut the other end right after the resonators where the pipe expands back to 2.25" :


Here you can see the pinch on the one pipe and you can actually see all the way through the resonators and mid muffler (I didn't realize the mid muff was actually just a resonator as well) :





 

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Discussion Starter #2 (Edited)
Next, I unbolted the rear mufflers and removed the remaining axle-back pipes to fab up to the replacemant pipe and X. I first test fitted in this order:


Then realized the X should be closer to the engine and connected everything like this:


Here are the factory pipes coming down from the engine after I cut out the mid-muff/resonators:





2.25" X-pipe is a perfect fit over the stock piping:

 

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Discussion Starter #3 (Edited)
Loosely connect everything and check fitment:



Insert rear pipes back into their hangars and zip tie to the sway bar for the correct angle:




Check fitment again:


At this point I was using 4 pipes that were 18" long each and I realized I'd be very close to the crossmember shown here:


So I removed the 2 sections of 18" pipe that were closest to the engine and replaced them with 24" sections to space it back further from the crossmember. After that, I cut 10" off of the rear 18" sections to make sure everything fit correctly again. NOTE: Do not just take 10" off and expect it to fit. Measure your own pipes when fitting everything to ensure a correct fit. I also used a pipe expander on the rear section of pipe shown here to slide over the existing rear pipes:


Next, I used a paint marker to show how far I wanted each piece of pipe to slide in side the others:


One final mock-up before clamping:


You should be all set to go! Just make sure everything is tight and inserted far enough in the corresponding pipes before clamping down. I didn't need to remove the crossmember to do this. I saw in another post that someone used washers to push the crossmember lower to clear the pipes, but in my case I didn't have to and although its close, I haven't heard the pipes banging on the crossmember at this point. After everything is tight, bolt your mufflers back up and don't forget to cut off the zip ties!

The car was barely louder than stock after finishing, so I did the washer mod (runs and hides..), I pulled the exhaust gaskets out before the mufflers and used one 3/8" washer on each of the lower bolts. It's still not loud at all and has zero drone. I did notice though that it does have a more exotic tone now, similar to a 350Z like I've heard others mention.
 

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Discussion Starter #4 (Edited)
Not the best quality videos, but here is a part-throttle drive by and a WOT drive by video. The intake actually overpowers the exhaust note at WOT.




Feel free to link any photos or videos here, I'm just trying to help you guys save a few bucks :)
 

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Thanks for the write up! It's good to know that you can run straight sections of pipe like that. That helps my own custom exhaust idea.
 

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Very nice write up. Mine was banging on the tunnel brace after I put on my headers. I clamped a piece of rubber from an old tire in between and it worked for a week before falling out. Now I have that section wrapped with thermal wrap (zip tied on each end to hold in place) and haven't heard a peep since.
 

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Nice job & Great write up! Saved yourself some coin.
 

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Discussion Starter #9
I had planned on putting headers on, but I really don't want to void what's left of the powertrain warranty.. especially considering I just purchased the car last month. If I do though, I'll probably keep the GT mufflers for the neighbors sake. I leave for work at 6:30 everyday.
 

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I had planned on putting headers on, but I really don't want to void what's left of the powertrain warranty.. especially considering I just purchased the car last month. If I do though, I'll probably keep the GT mufflers for the neighbors sake. I leave for work at 6:30 everyday.

Good call, my neighbor is an A-hole, somtimes I even rev it in the morning to wake his ass up. Must be nice to have a decent neighbor.
 

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Very nice write up. The sound is great. Most people say the car doesnt seem luuder after this mod but maybe that is inside. On the outside it sounds great! Did you notice any seat of the pants improvement on the butt dyno?
 

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Discussion Starter #17
I used a pipe expander from advance on mine, heating it up first is probably a good idea. I had someone else wrenching on the other end of it because I didn't want to clamp the pipe to anything to hold it while expanding. It doesn't need to open much, the new pipe is already larger, but just not quite enough.

I really dig the sound, but with the rear mufflers off it sounds like a tractor at idle, so straight pipes are out. Keep in mind, I did the washer mod at the same time, so it's a little louder than stock would be with just an X-Pipe.
GXP muffs would sound great from the other clips I've seen, but I'm still up in the air about LTs and if I do end up installing those, it'll be too loud uncatted for me.

No SOTP difference, I'm sure the gains are minimal anyway. It is louder inside the car, but that's from the washers I'm sure. Its definitely a different tone though.
 

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Oh ok didnt realize you did the washer mod too. Thanks for the reply. Hoping to get mine done this week if I can get 5 min of car time.
 

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Discussion Starter #19
Assuming you already have everything it shouldn't take more than 2 hours. It took me about 4, but that included stopping to take pictures, a parts run for the longer pipes and washers, and mocking everything up several times so I didn't cut too short. Its easy work really, it welding isn't a must I'd recommend to everyone. Although ideally a 36" pipe would've been nice for a cleaner install, but its not like I'm ever going to see it anyway.
 

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Good call, my neighbor is an A-hole, somtimes I even rev it in the morning to wake his ass up. Must be nice to have a decent neighbor.
LOL, I needed a laugh!

Where did you end up going to have your X pipe installed?
 
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