No problem, glad I could help out. I never measured my stock Y pipe before I sold it unfortunately, but I did take this picture of it next to my 3" one if its of any use

 

That's a noticeable difference. Which aftermarket Y-pipe is that? I was under the impression that you had only installed the Manzo Y-back, and the rest was stock.

So the Manzo 2.25 midpipe is boltled up to the Y-pipe shown above?

 

Yessir. My full exhaust setup is Kinetix Racing HFCs, 3" Y pipe, and the Manzo Y back exhaust. My Y pipe is unbranded but here's the link: http://www.ebay.com/itm/Y-Pipe-Catless-Straight-Downpipe-Exhaust-FITS-Nissan-370z-Infiniti-G37-/262121370847?vxp=mtr&hash=item3d07a6b4df
I ended up getting the aftermarket Y pipe because I stripped a stud on my OEM one while installing my HFCs. So I ran the 3" Y pipe with the OEM Y back exhaust for a while before I got the Manzo. I couldn't tell any difference in exhaust tone or volume after changing just the Y pipe. And my car had Stillen HFCs installed when I bought it, so I'm not sure what my Manzo would sound like with OEM cats sadly. It's pretty mellow even with my Kinetix HFCs

 

I heard Kinetic hfc have rasp. Does yours?

So you have Kinetic HFC -> Ebay 3" Y-pipe -> Manzo Y-Back exhaust.

Got any sound clips?

 

After roughly 5,000 miles there's just the tiniest bit of rasp audible from behind the car if I rev it really hard. It's not audible in the cabin though.

Right after installation:

5,000 miles later (also switched to a lightweight flywheel so it revs differently):

Interior 5,000 miles later (windows up):

 

Sound really nice!

 

^Thanks man. I was expecting to have to change the mufflers out after a while, but it's holding up amazingly well

 

So you were able to run an ebay 3" y pipe with the stock exhaust back? I don't understand how that would even seal.

 

hit up Megan Racing for their ypipe - it's a quality piece at a good price. I ran the same ypipe on my 06 M35. the outlet was 3" and it didn't cause an issue to the Megan midpipe 2.5" (I ran a lot of different exhaust combos)

Megan Racing

 

I'm sure your setup worked with the Megan 2.5" midpipe. The guy I quoted said he ran it with his OEM y pipe which is like 1" in diameter lol. My plan is to run a Tanabe axle back, ebay mid pipe then have the rest custom made locally.

 

You'll need to have the midpipe modified to fit the Tanabe because the Tanabe doesn't have flanges.

 

Right, it would be custom from the Y pipe back. Not sure if they make v bands the small size of the tail pipes going into the mufflers, but I'll definitely try.

 

Yessir. The flange on the stock Y back has plenty of meat on it, so it sealed up to the 3" Y pipe with no leaks at all. I posted a pic in post #31 comparing the 3" eBay Y pipe with the stock Y pipe outlet

 

nice sound