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The stock exhaust is rather pathetic. My 7th gen Maxima just had an issue with the passenger side muffler pipe broke and separated. Rust is an issue here in Ohio but I’ve never had an issue like that with other cars I’ve owned. The Q50 OEM exhaust seems to be of similar construction.
 

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I guess I’m a lucky one. Did a custom local shop for my exhaust and don’t have any drone or rasp. I also have Megan LDPs, so I just went with 2.5 dual pipes into flowmaster mufflers. No Y or X pipes, no resonators. I do kinda wish I went straight pipe, but I’m sure my neighbors are glad I didn’t. Lol
 
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Discussion Starter · #23 ·
I guess I’m a lucky one. Did a custom local shop for my exhaust and don’t have any drone or rasp. I also have Megan LDPs, so I just went with 2.5 dual pipes into flowmaster mufflers. No Y or X pipes, no resonators. I do kinda wish I went straight pipe, but I’m sure my neighbors are glad I didn’t. Lol
If you don't mind, do you have a pic of it or maybe further specs? Would love to copy a decent exhaust without a lead time.
 

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One's been engineered and tested, the other is a bunch of welded pipe.
Can you show any appreciable difference in power on an equally sized system? Unless someone is planning to own the car to 200k miles, the majority of the differences in exhaust are for tone (which is to taste) and how much they take from you bank account.
 

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My exhaust is custom fab using Borla for my X Pipe as well as Borla mufflers and tails. It is paired with Megan LDPs. Great low tone. I'm too old to have drone while cruising, and this set up serves me well.

Also have WMI set up. Happy to share.
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If you don't mind, do you have a pic of it or maybe further specs? Would love to copy a decent exhaust without a lead time.
Wish I did but I was at work when it was being done, so aside from a pop in during the build, I wasn’t able to watch. I can try to get with my exhaust guy, but he has since had hand surgery and his shop is now for sale.
 
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Discussion Starter · #29 ·

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@95nBlown In b4 you get hammered about the quality of your welds :ROFLMAO: . Looks good. How loud is it on a cold start?
Yeah, some of those welds look marginal but I prefer mandrel-bent tubing which most muffler shops can't fabricate because of the cost of mandrel bending equipment. Compression bends that the fabricator obviously used to make that exhaust significantly reduced the diameter of the pipe, slowing down the exhaust gas velocity, reducing HP and torque because of increased back pressure and turbulence, and also increasing heat. If that's 3" tubing, each of those compression bends has likely reduced the inner diameter to around 2 1/2" or even less. You want to eliminate back pressure while maintaining exhaust gas velocity. Even though the rest of the exhaust is 3", those compression bends essentially make the entire system 2 1/2", as they act like orifices.

95nblown is happy with his exhaust, so drive on. It is not my intent to throw shade on his particular exhaust, but rather point out the general issue of mandrel-bent vs. compression-bent exhaust piping.
 

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Yeah, some of those welds look marginal but I prefer mandrel-bent tubing which most muffler shops can't fabricate because of the cost of mandrel bending equipment. Compression bends that the fabricator obviously used to make that exhaust significantly reduced the diameter of the pipe, slowing down the exhaust gas velocity, reducing HP and torque because of increased back pressure and turbulence, and also increasing heat. If that's 3" tubing, each of those compression bends has likely reduced the inner diameter to around 2 1/2" or even less. You want to eliminate back pressure while maintaining exhaust gas velocity. Even though the rest of the exhaust is 3", those compression bends essentially make the entire system 2 1/2", as they act like orifices.

95nblown is happy with his exhaust, so drive on. It is not my intent to throw shade on his particular exhaust, but rather point out the general issue of mandrel-bent vs. compression-bent exhaust piping.
If I was looking to not daily drive my car around, I would have gone mandrel bent exhaust at a significantly higher cost, for sure. Not an investment that would yield significantly more from the platform, in her current state. So, I opted not to go mandrel for now, just open her up a bit to breathe more.
 

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Yeah, some of those welds look marginal but I prefer mandrel-bent tubing which most muffler shops can't fabricate because of the cost of mandrel bending equipment. Compression bends that the fabricator obviously used to make that exhaust significantly reduced the diameter of the pipe, slowing down the exhaust gas velocity, reducing HP and torque because of increased back pressure and turbulence, and also increasing heat. If that's 3" tubing, each of those compression bends has likely reduced the inner diameter to around 2 1/2" or even less. You want to eliminate back pressure while maintaining exhaust gas velocity. Even though the rest of the exhaust is 3", those compression bends essentially make the entire system 2 1/2", as they act like orifices.
All theory....IRL much of what you're saying is negligible except in corner cases. Is $1000 worth 10hp? Different strokes for different folks I suppose, but the majority in this class of car would rather spend the money elsewhere on other mods.
 

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If I was looking to not daily drive my car around, I would have gone mandrel bent exhaust at a significantly higher cost, for sure. Not an investment that would yield significantly more from the platform, in her current state. So, I opted not to go mandrel for now, just open her up a bit to breathe more.
Like I said, if you're happy, then drive on.
 

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Discussion Starter · #37 ·
All theory....IRL much of what you're saying is negligible except in corner cases. Is $1000 worth 10hp? Different strokes for different folks I suppose, but the majority in this class of car would rather spend the money elsewhere on other mods.
Honestly I don't believe I will be pushing the kind of power anytime soon that makes the CBE my bottleneck. Plus I have Megan Racing LDPs which are 2.5in anyways.
 

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Honestly I don't believe I will be pushing the kind of power anytime soon that makes the CBE my bottleneck. Plus I have Megan Racing LDPs which are 2.5in anyways.
There's nothing wrong with planning a head and doing it once instead of paying twice for something. I'm simply saying that if youre not going max effort and putting mirrors under your car at a car show, consider a bang for the buck setup. You already know you'll end up tuned and WMI at some point so plan now ;).
 

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@nickdaria Look up Speed Culture Studios on YouTube. He's got an exhaust system that he had custom done. His car is a 3.7L but you can source the same components for the 3.0L.
 
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Can you show any appreciable difference in power on an equally sized system? Unless someone is planning to own the car to 200k miles, the majority of the differences in exhaust are for tone (which is to taste) and how much they take from you bank account.
There would be a restriction in the upper rev range but it wouldn't be much. I can't give real world number because I haven't tested it but my wildly inaccurate guess would be something like 10-15rwhp/tq at 6000rpm+ once you get past 425rwhp and go up exponentially from there. There would be no noticeable difference in everyday driving.

If the shop doesn't have access to a mandrel bender, you can buy two 90s and two ~15° bends for about $150-$200 to replicate the exhaust shop version above. They would just cut n weld up. Those welds won't last as long as normal because they probably won't fill the tube with a nitrogen before welding. It will still last many, many years though.
 
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