Maxima exhaust saga

Manifolds to tailpipes, this can be quite exhausting
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Maxima exhaust saga

Post by kevm14 »

I will flesh this out more in the near future but the quick and dirty version is, I did a cheap eBay stainless catback like 6 months ago. And it badly needs a flex pipe. But the flex pipe is integrated into the Y-pipe, which contains pre-cats. New OEM is outrageous. New aftermarket is like $300+. New performance aftermarket starts around $225 or $300+ for stainless. I am going the $40 universal flex pipe route.

I have the parts...I should post P/Ns and pictures.
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

Re: Maxima exhaust saga

Post by Fast_Ed »

I am interested to see how this turns out. We need a better way to take pictures while working on this stuff.

Currently, my phone gets all greasy and the dirtiest (and therefore most interesting) parts of the job go undocumented.

Too bad you cant weld stainless easily. Guess you'll have to give it 'The Clamps.'
Adam
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Joined: Wed Oct 23, 2013 9:50 pm

Re: Maxima exhaust saga

Post by Adam »

Fast_Ed wrote:I am interested to see how this turns out. We need a better way to take pictures while working on this stuff.

Currently, my phone gets all greasy and the dirtiest (and therefore most interesting) parts of the job go undocumented.'
I have Amanda's old digital point and shoot. I don't think she cares about it any more or even remembers she owns it.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxima exhaust saga

Post by kevm14 »

I actually have an old Samsung P&S that I had before my Fuji (which is also 5 years old). It takes AA's which is actually good as I can use NiMH.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxima exhaust saga

Post by kevm14 »

New 2" flex pipe and band clamps. One thing I am concerned about is the Y-pipe is not perfectly round. It has a weird hump on part of the circumference. So I may have to use some heat in combination with my pipe expander and a BFH. This flex pipe has to slip over that pipe.
WP_001044.jpg
I also need to constantly remind myself not to cut the Y-pipe to fit the length of this flex pipe, but a few inches short, to accommodate the amount of slip-over on each end. I can easily see myself doing that if I don't pay attention.

Also, here is my current situation. Some fiberglass header wrap, painted with special high temp paint. Two layers of this. Rips right in the middle.
WP_001042.jpg
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxima exhaust saga

Post by kevm14 »

I measured the Y-pipe on the car using a ziptie. I wrapped the ziptie around the pipe, then marked with a sharpie where it started to overlap (circumference measurement). That came out to about 6-3/16. Divide by Pi and that comes out to about a 1.97" outer diameter. Which is why I ordered a 2" flex pipe.

Well I just measured the OD of my flex pipe. I guess it's my lucky day as that came out to 6-13/16 which is 2.17" OD. That should slip on, as long as I can beat down the hump. I may get to it later today. Or tomorrow. It'll be nice as I've become tired of the racket. It's a fart can exhaust but it's not supposed to be THIS loud.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxima exhaust saga

Post by kevm14 »

Don't have time for a full post, but I installed the flex pipe. The OEM Y-pipe has quite thick walls.
S7302405.JPG
The flex pipe was quite shot.
S7302404.JPG
Fitting it up. I cut the cat side of the Y-pipe three times total. The engine side I just cut flush with the weld on the old flex pipe.
S7302407.JPG
All finished. The front band clamp is far from ideal. I didn't have much pipe to work with and it's curved, too. I tried expanding it but even with heat and an impact on the expander, that thick wall pipe is just a bitch to work with.
S7302409.JPG
It makes quite a hissing sound over 4000rpm, which also means the stock cat is pretty restrictive, since the cat-back is all straight through 2.5".

I will probably have to replace the front band clamp with a U-clamp and hope it crushes enough to seal. I think all the nasty resonation from having a hole in the flex pipe is gone, but the hissing over 4000rpm @ WOT is annoying.
Fast_Ed
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Joined: Wed Oct 23, 2013 9:45 pm

Re: Maxima exhaust saga

Post by Fast_Ed »

That repair is a huge improvement over what was there. Nice post too!

Maybe slather some muffler weld gunk in there when you replace the clamp. Better mechanical fastening plus that stuff will fix that leak I bet.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxima exhaust saga

Post by kevm14 »

I switched to U-clamps. And added the goop. To diagnose the leaks, I fashioned something to plug the exhaust. It's huge so a rag wasn't enough. I ended up stuffing the old bump stop from my rear shocks into the muffler, then inserted a 3/8" drive extension and the rag held all that mess in place. It actually leaks in multiple places, one of which I didn't touch (at the rear of the cat). The U-clamps couldn't get it leak free unfortunately, and I tried clocking them different ways. The front one actually fared better. It turns out the rear was leaking more the whole time.

I did try some fiberglass stuffed around the band clamp on the front, and I think that worked alright. I could have tried that on the rear, but I got annoyed and just switched the U-clamps. Hopefully the weld crap will hold. Needs time to cure.

Driving around normally (before the goop) is a lot better. Sort of sounds like a turbo when you get on it, since the backpressure ramps up with the engine's torque curve.

U-clamps:
S7302420.JPG
With goop:
S7302421.JPG
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxima exhaust saga

Post by kevm14 »

Eh, it didn't fix it. I'll have to look at it some other time. At least the car is less obnoxious when I start it up at 6am.
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