It took about half a year, but I finally got my exhaust system set up and on the car.

I started off with buying the Gruppe-S Y-pipe in a groupbuy 6 months ago, but since I wanted to portmatch everything before it was installed, it took me a long time to get all the components. The Y-pipe has an approx. 3 inch exit, and the stock midpipe is 2.5 inches.

I bought a Japtrix B-Pipe to match up with the Gruppe-S Y-pipe. It's a 3 inch pipe the entire length. But the strange part, is that the flange at the opening is only 2.5 inches! Also, the 350z B-pipe is shorter than the G35 one, so I had to buy the 8 inch extension at Performance Nissan.

I really wanted to keep the stock muffler, since I like the sound, and I'm no longer interested in loud exhausts. But the stock muffler inlet is 2.5 inches. So I bought the reducer cone and flange from Chuck at Dr. Gas. I also bought another 3 inch flange to replace the 2.5 inch one on the Japtrix.

I spent a few days portmatching all the components before going to Speedway Muffler in Rowland Heights. I got there early in the morning, and was out in 1 hour. This is what I had them do:
Install Y-Pipe and Extension
Cut off 2.5 inch flange at opening of Japtrix B-pipe, replace with 3 inch flange, and bolt it onto the extension
Cut off early part of stock muffler's 2.5 in piping, and weld the reducer cone to place.

I still have to take some pics with everything bolted up.

Overall the car sounds just like stock, just a bit deeper. Maybe slightly louder at high RPMs. I'll dyno on Saturday at Church's and see if I got any gains/losses. I've got plenty of "baseline" dynos there.


This is halfway through portmatching the reducer. I just did gasket matching for this application.



Here's the performance Nissan extension pipe with the portmatching, and some polishing. I didn't have as much time to polish as I did with the intake manifold and lower plenum stuff.



Here's a pic of the extension pipe bolted onto the Y-pipe with everything portmatched, and slight polishing.



If anyone in Socal wants a stock coupe midpipe, I'll sell it for $100.

 

Nice job once again E_K. I'm looking forward to checking out your latest mods this Saturday.

 

Thanks Dave. Hopefully it'll show some gains on Saturday.

Here's a pic of the Y-pipe. Nothing people haven't seen before.


Here's a pic of the extension pipe. The flange farthest on the right is the 3 inch one that I bought from Dr. Gas. The guy at Speedway Muffler said the 3 inch flanges are hard to come by, and he thinks maybe that's why the B-pipe came with a 2.5" one. Who knows...


And the reducer cone with stock muffler. I actually took the muffler down after I got home, and refinished some of the inside piping.




Here's some interesting pics of the stock exhaust.

Down the stock Y-pipe:


And here's a interesting view. It's the piece of the stock muffler that was cut off, bolted onto the end of the stock mid-pipe.


The stock system actually lines up very well together. The inside passageways are only 1mm off at most between components. There wouldn't be much need for portmatching with the stock connectors. But the aftermarket stuff definitely needs it. If I didn't portmatch, and just bolted everything on, there would be several places where the air would hit a 5mm to 8 mm wall.

 

Nice job and nice write-up. I'm interested in your dyno results. Please keep us updated.