New Custom Exhaust Single Exit 3.5''

Megan370z

For the past 3 weeks I've been working in my basement on my Version 2 of Megan's Exhaust.

After about 60 hours of work I finally got it done !
Basicaly the setup is;
Modular Y-Pipe setup with the choice of either 2x Resonator or 2x HFC
Y-Pipe include a transition edit: Deleted Secret matterand a megaphone of edit: Deleted Secret matterto 3.5''OD
The Mid-Pipe include a big 3.5'' Resonator
The Muffler is a straight flow.
Using only V-Bands ( then machined by me at work.)


EDIT;
Some peoples request a Fly-by video !
Here it is as requested.

Yeah its dark, but who care ? the noise is still noise !
Video took from a GoPro HD




It is very loud by 3500rpm, in the video 0;56 to 1;06 mark, it is where I was shifting at 3500rpm.
Cruising at 80km/h (50mph) the exhaust is actually very quiet which I was quite surprised ! but anything higher than 65mph will require a bit more voice strength if you want to keep a conversation with your passenger.




This is using the shorty Momentum header, there was a plan in the beginning to modify it right at the collector but I decided to ditch that idea because of a future plan.
But the planned transition was still used on the exit flange.


Everything started about 2 months ago when I was thinking what I should do about the exhaust problem since my previous one was just a prototype and was too heavy.

The idea has been fixed for a Single exit that would be using the center exit on the OEM bumper. Since there will be a flat underbody & diffuser made, this was the smarter way to do it properly.

So let start with the beginning when I received the parts !

Part Order # 1
Mandrel U-Bent in 2.5'' & 3.5'' ... V-Band . resonator/HFC/muffler




Part Order # 2 (From burnsstainless.com)
Some transition & megaphone
Then the V-Bands that I received from Order #1 which I machined at work for an optimum flow.




This is the first part that I started working on , the Y-Pipe.
The goal was to find the right angle cutting setup using an online software.




The Result of it ?
This, forgive me if one side is longer than the other, it didn't matter.






Then once I cut both Transition & Megaphone as what my plan was it ended to be 1/8'' off in length but this was due to the V-band ! so I successfully made exactly what was planned on paper !
14 1/8'' Long




Once the center piece of the Y-Pipe was completed I started to work on the headers & Shorty Test Pipe.
You can see that I welded the transition directly on the flange




This is how it look on my spare engine. !



The next step was to make the modular part of the exhaust, similar to what Motordyne does with their XYZ Y-Pipe
But this one is before the actual Y-Pipe section.
You can see my clearance guide (aka the coat hanger )




Once completed !
From top to bottom
-Modified Momentum header + shorty test pipe & modular resonator
-OEM Header & Cats
-PPE Step header




So of course I had to test it on the car itself to make sure everything was spot on for both side with the best ground clearance possible I actually gained about 1/2'' of ground clearance over the PPE.






Now, I was back to the Y-Pipe section.
This is to show the difference between;
-OEM Y-Pipe
-my 2010 custom X-Pipe (has a shorter flow path than OEM !)
-Future Y-Pipe configuration (an even shorter flow path than previously )
The resonator are actually facing toward the Y-Pipe to help with the flow path but I was restrained by the actual transmission support bracket.




So Y-Pipe ver.1 did not work correctly due to an unforeseen clearance issue with the driving shaft, the next idea was to modify a couple bent to have it off-centre going toward the passenger side (corner balance in mind...)
a few hours later this is what the project came down.




A closer look at the Y-Pipe.
Keep in mind that the last time I welded Stainless was back in school 10-12 years ago and 7 years ago as a welder before joining the Army. I got my first welding machine in May 2013 which is a AC/DC Tig welder. !
After a few practice weld I was ready to go on the real thing !




At this point I was now gonna need the Z on 4 jack stands for the rest of the exhaust.
For those who does follow my Journal knows that I talked about removing the rear tower sub-frame brace to make something similar like the 350z.
During a prior inspection and evaluation of my project, I discovered that our 370z share a very similar underbody bolt pattern and it appear that we could most likely use the bracket that I am looking for .
Unfortunately my closest Nissan dealership fail to find that bracket in their system so I had to think about something else which finally ended to be something very easy to do ! Yeah me.


This picture show the difference between the 350z & the 370z
There is 2 pre-threaded nut into the 370z frame where on the 350z is it used for the bracket that I was looking for.


This is what I made.
Sorry about the baby blue color but its the closest thing I had here . ;(
The 2 outer nuts are just there as a spacer since I didn't had the right length of bolts and didn't want to cut them. then the 2 middle bolts are welded at the bottom and the nuts on them are also there as a spacer then the 2 top nuts are there to hold the actual sub-frame brace.
No modification to the 370z brace. just a few flip backward and 180degree turn and it ended at 1 1/2'' from the frame. The setup use 1'' square tubing this is why the use of the nuts as spacer.


Once installed


Muffler clearance.


You see what the goal was ?




So no more picture but I plan to remove the exhaust from the car tomorrow for some more pictures and fixing a small issue that happened while welding the mid-pipe.


The exhaust was 95% completed on Thursday and I had to go for a drive !!!
I was more than happy about the noise of it !
It does not have an high pitched noise like a normal Y-Pipe setup but a very shaky base sound that can make you shake !!!!

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