Since my engine is basically an HR stroked to 3.7L (VHR crank)
I thought maybe I could share my new custom exhaust with everybody.



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 !

The exhaust setup shown on this picture has been weighted at 39.6 Lbs.
This setup is currently 33 Lbs. lighter than my 2010 custom exhaust but it was made to be within a specific track noise decibel.


Basicaly the setup is;
Modular Y-Pipe setup with the choice of either 2x Resonator or 2x HFC
Y-Pipe include a transition 14deg and a megaphone of 6.5deg going up to 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.)
Ground clearance is exactly as the OEM exhaust on the 370z.


Edit;
Fly-By video is UP !!!!

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



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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.



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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 ?




This picture was taken when I was working on the Mid-pipe . It wasn't that easy going in & out & of the house & under the car after everything minor change in cutting/sanding.


Some bungs welded !


This is earlier today when I welded the rod support on the mid-pipe


The look without the rear bumper cover. Can you visualize a future true diffuser ?



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 !!!!

 

Awesome...props for doing the work yourself!

moar videos exterior flybys

 

Awesome work!! I like the sound as well, but would love to hear what it sounds like as a bystander. Possibly a flyby vid??

EDIT: lol beat me to it King.. ha

 

request accepted,

well I was supposed to make a few flyby video tonight. Unfortunatly it probably wont happen but tomorrow I'm doing it

 

Pic of the tip going through the rear bumper? "No pun intended"

 

no problem,
but keep in mind a whole new setup will be made and the bumper will be cut within the next couple month which a true diffuser will be included into the project.

I will post the actually picture of the current setup tomorrow as its getting dark already here ;(

 

Group buy?

 

Im actually thinking custom 3.5" from y pipe back like SG did.

 

Wow man, beautiful custom work; must have plenty of helmet time to be able to lay down beads like that. In for flyby vids.

 

props man, very nice work!

for the next setup, you going to keep the exit in the center or on a side?

 

Dope custom work. Actually very impressive than other hack jobs I've seen on here

 

well. first you would need a 370z !

and if you do then lets do some math.

it took me;
-60hours
-2400$ of parts ( tx & shipping included)
-1x bottle of Argon 75$
-80$ shop supply (cutting disk/dremel stuff.......)
-175$ (on my lunch time at work 1 hour of machining the V-Bands. (Army cost per hours on tech. at my level )

lets say I charge 25$/hours on the cheap side.
that's 1500$ in time. adding everything bring the cost of this unique part at 4230$

Now you must add the price of the Momentum headers or the Z1 copy of them at what ? 800-900$ ?

so lets make it a 5000$ complete custom exhaust !

the next exact one could take a third of the time maybe ... so that's 1000$ cheaper !





More seriously I must thanks Sasha @ Onpointdyno.com
With his very aggressive cams, his 3.5'' made a lot of power Vs the dual exhaust. I was just looking to make something similar with some tweaking which should in theory work.
and of course I didn't want to have it too loud which is why I made a Modular Y-Pipe , Thanks to Motordyne whos I copied & tweaked in the pass with their M370 intake.
My Y-Pipe configuration was somewhat inspired of their XYZ Y-Pipe.

It took me a flat 10 mins yesterday doing the switch of 2x Resonator to 2x HFC.


edit ;

the next setup is to have a diffuser made , this is why I made a single exit in the middle . I don't particularity like seeing a muffler or exhaust exit on the side of a diffuser... but again this will be in the next couple months.

 

Fly-By video is UP !!!!

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



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Awesome man...nice deep tone, other 370zs I've heard don't retain the VQ note well. This setup however sounds perfect!

 

Doesn't even sound like a VQ 2 me

 

Gotta agree with Kingbaby in that I've never heard such deep notes come from a 370 exhaust, taking into account the different ways and equipment people use (usually an IPhone) and all of the variables I've never heard a Z exhaust like it, unique and beautiful with it. A fantastic write up.

 

You guys know its a hr right?

 

Yup its mostly an HR engine but stroked to 3.7 Since I kept the VHR crank/rods setup from my blown engine.
Running on the HR ECU into my 370z.

So it should sound like a VQ ! heheh


But what is strange for me is the in-between shift, it seem like the exhaust (Y-Pipe + modified header) is making a ton of vaccum to expel the exhaust gas from the cylinder chamber.More than what im use to hear on different exhaust setup on Youtube. Which is perfect for scavenging effect
If im totaly wrong on this, let me know.

 

Sounds good especially the last fly by. The whistle from the intakes make you sound boosted.

 

OEM Intake. hehe