Hi folks... so I’ve spent a while going through the various threads on this subject in this forum over the last couple of days and have found a few threads on the topic but none that are definitive on this topic. Here’s what I have gathered as credit to multiple threads...


What I am trying to ascertain is whether I would have any issues with either rasp, performance impediment, flow issues if I just upgraded my y-pipe on a G37x sedan from stock to one with 2.5” inlet / 3” outlet... which I believe the Megan Racing pipe is.

I would appreciate any thoughts on this.

 

So to clear any uncertainty around my baseline I took the plunge under the car in the cold on the weekend and checked it out. The outlet of the cats to the inlet of the y-pipe is 2.25"; the outlet of the y-pipe to the inlet of the axel-back is 2.5" - this is stock and for the all-wheel drive.

So in my case the Megan Racing y-pipe will look like this?\:
stock cats 2.25" outlet --> y-pipe 2.5" inlet
y-pipe 3" outlet --> stock axel-back 2,5" inlet

Talking to a couple of exhaust shops about this - one said that it will be fine to mate up just like that without any special connectors and will not have an impact on performance but it will become louder.
The other shops said that this setup will work fine with just gaskets and no special connectors and didn't comment on noise.

Does this make sense and the same as what any of you who have done this here have experienced? As for the sound - any feedback on what loud means? I am okay with loud as long as it isn't raspy or too "drony" at cruising throttle position.

 

I don't see any issues with your setup.
My first setup was stock cats > stock y pipe > Top Speed Y-back exhaust (2.375")
I then added a Motordyne Y-pipe: stock cats 2.25" > Motordyne y-pipe (2.5" inlet and 3.0" outlet) > Top Speed Y-back exhaust (2.375" inlet)
Shortly, I added Circuit Werks test pipes: Test Pipes (2.25" inlet from header and 2.5" outlet) > Motordyne y-pipe (2.5" inlet and 3.0" outlet) > Top Speed Y-back exhaust (2.375" inlet)

Here is a video clip of the 2nd (stock cats) and 3rd setup (test pipe).

And another video of the 3rd setup driving

 

Does the Megan Y have a resonator integrated into it? If not, I'd consider getting one welded in. Panda's set-up has the resonated Motordyne Y which gives it that great sound in the video. I went with an unresonated Y pipe and after my testpipes were installed and it was RASP CITY. With the stock cats tough, the exhaust sounded great! Something to consider if you end up replacing the stock cats.

Here was my set-up with an aftermarket Y-pipe, and the Top Speed Y-back (stock cats):

 

@projectpanda13 and @RMB5190 both your setups sound amazing!

The Megan Racing y-pipe is unresonated. But would it necessarily add that much more noise and rasp if the rest of my exhaust will be kept stock (for now anyway)?

That being said I did discover a local shop to me that makes a custom XYZ pipe which is resonated that I am considering. They also boast greater performance gains than a typical y-pipe system.
(EDIT: The shop is selling the motordyne) :-) But it is double the price of the Megan Racing off eBay. Wondering if it is worth it.

https://whiteheadperformance.com/pro...ab-description

Thoughts?

 

I cant say for sure. My unresonated Y pipe sounded great when paired with the stock cats and Top Speed Y back. As soon as the test pipes went on, it was another story.

 

did it get much louder?

 

Oh yea, super loud and RICE. Wasn't until the Vibrant resonators went on did things get right.