Yesterday I received my coupe midpipe and decided to throw it on this morning. When I had been under the car to install my Borla TD (sold long ago after 3 days use), I took notice at all the rust on the nuts at the y-pipe/midpipe junction. 3 years of salty Midwest winters and thermal shrink/swell took it's toll on the nuts. Since I knew it would be a biatch to break the nuts loose, I took the wife's car to the hardware store and bought a quality rust penetrant. I got home and applied the penetrant and tapped the exhaust with a rubber mallet to work the liquid in. I jacked up the rear of the car which is always fun with the low 350Z drop. I attempted to break the y-pipe/midpipe nuts loose with a 14mm socket, but that wasn't going to happen. I then got out the 18" breaker bar. No go and in the process, the nuts started to round off. Fabulous. Now I got out my Dewalt bolt/nut extractor kit and hammered on the 14mm extractor socket. Due to lack of space by using the extractor socket, I could no longer use the breaker bar under the car. Instead I had to use an adjustable 10" wrench. Yeah, I about gave myself a hernia trying to free the bolts since I didn't have much leverage with a 10' wrench. I faced the music and accepted that I had two options:

1) Say screw it and take the car to a shop, have them cut the bolt/nut, drill out the old bolts at that flange, install new bolts/nuts/coupe midpipe. That would be $80-100.

2) Remove the y-pipe and midpipe together (which is 70lb SOB), put the unit out in the yard, and give it another shot with the breaker bar/extractor since clearance would be a problem. If that didn't work, them it was on to the Sawsall, cut the bolt/nut, drill out, go back to the hardware store and get new bolts and nuts.

I'm cheap so I went with option 2. I quickly got the y-pipe/midpipe off the car and in the yard. I put the breaker bar/extractor to the nut, but all I was doing was pushing/lifting the exhaust unit when trying to break the nut loose. That wasn't going to work. In a moment of frustration, I stood up, and stepped on the breaker. The bolt broke loose. I switched to the remaining bolt and did the same kick method and it worked! Luckily the threads on the bolts were fine and the only damaged part through the whole ordeal was the nuts which obviously get chewed to hell from the extractor. Luckily I had some old nuts from my Maxima that worked as placements.

After 2 hours of screwing around with a 20 minute install, I finally had the coupe midpipe on. I started the car up and was met with a nice little growl and a healthy burble. I got underneath the car and checked for exhaust leaks. All good. I got the car on the ground and went for a drive. At first there was hardly any difference in noise, but as the exhaust quickly warmed, the noise difference was quite noticeable. From normal part-throttle acceleration to 40mph, there is heathly deep burble/tone under load. On cruise there's no difference. On deceleration in a lower gear, there is a cool burble. At WOT, there is a pretty big difference, especially above 4000rpms. It use to be all I'd hear in the 350Z pipe. Now I can hear some exhaust too.

While I was cruising I came up behind an auto G35 coupe and I listened to his exhaust from a stop and cruise. There is a distinct difference between my setup and the coupe's. The coupes tone is higher and more warblely. My G has a deeper and more hollow sound. I'd have to say my setup is a bit louder than the coupe's. Overall I'm pretty happy. The car finally has the sound it deserves. Next up is a nice set of exhaust tips.

 

I took my car to a shop to take my exhaust off for Stillen Gen2. The OE Y-pipe and mid-pipe have the rusted look. Thank god my car is just 6 months old. None of the bolts are badly rusted. They are rusted but I didn't have the problem that you had. The shop took them off with a few tries. Brave guy...

 

I had the same problems with the bolts on the y-pipe to midpipe connection. I had just about given up but knew it had to get done. I think I tried about every tool in my toolbox.

I think this was my favorite mod - maybe because of all the trouble it gave me. I agree with you about the sound.

Let me know what you find in terms of exhaust tips.

 

haha Dave. Your story cracked me up. Our NW weather is much nicer to bolts and such. Now to find someone that's selling one.

 

why cant they just put stainless steel bolts on our OEM exhaust systems

 

I finally did mine yesterday as well. The only problem I had was I left my tools at home (did the install in my dad's garage). He doesn't have too many metric tools so I ended up running out ot the hardware store to buy a 6 point 14mm socket. When I tried with the 12 point first, it started to round it off. It came right off with the 6 point socket and a breaker bar.

I only went for a quick drive, but it sounds much better.

 

you know that's a good idea, anyone have any idea what size bolts nuts are under there, and what size gaskets as well?

 

I didn't know there was a difference in the Y pipe from the sedan and the Coupe.

 

There isn't, the only difference is the mid-pipe and rear section

Glad you enjoyed the new sound of the mid-pipe Dave. Its great and yes, it does have a different sound altogether, but once you get both up the tach, they both make the same howl. Makes me wonder if I can stuff a coupe muffler down there to make it a quiet warble like the coupe at low-rpm and run pseudo dual-exhaust like how some of the Maxima guys are doing it.

 

Bro I had a very similar experience last Friday when I installed my 05 sedan middy. Bolts were rusted, rounded, etc. Had to cut them, worked like a charm.

 

P.S you guys won't be disappointed if you get the HKS sports muffler to go with your upgraded mid pipe, the sound is subtly louder yet more aggressive and performance sounding. Not all ricey like a motor boat.

 

really a diff in Y-pipe? we all know about the diff in the mid pipe which is why a lot of make the Mid pipe swap, but I have never heard of anyone making a y-pipe swap from coupe to sedan.

 

DaveB,

My younger brother made the same swap as you did on his '04 6MT Sedan. I have to admit, I like the way it sounds, now. Much much better than before. I have to hand it to you guys for crawling under your cars and doing this . . . You guys are nuts. Must be nice to have a young and strong back.

Hey, congrats on your install and enjoy.

 

I didn't change the Y-pipes. I just removed the Y-pipe/midpipe together so that I could the unit in my front yard to work on breaking the nuts loose. After the nuts were broken loose, I reinstalled the y-pipe.

 

The install took about $400 in tools

18" breaker bar
rachet
mallet
sledge
14mm & 12mm socket (12mm to remove driveshaft cross bar)
14mm extractor
14mm racheting wrench
3 floor jacks
9" wood blocks to put the rear tires to safety support the car
flat head screw drivers

With air tools and a lift this install would have been cake. One of these days I'll have both

I'm 32 year young, but my body is beat to hell today.