I’m building a custom exhaust to closely resemble the ISR exhaust because it’s my absolute favorite besides the RS*R Exmag GT2 that’s long since been discontinued.

I chose to go custom because my downpipe and midpipe is 3” and the isr exhaust has 2.5” piping. I’m trying to figure out what the outer diameter of the muffler is but having trouble finding that spec anywhere. I’m thinking it’s something like 5” or 5.5”

I overlooked the outer diameter when I purchased this muffler so I have to exchange it with a slightly larger one

 

ISR's website lists the diameter at 4" for the muffler tip

 

Based on my old pictures from when I had one, I think it was a 6 inch diameter muffler.

 

Correct. I’m looking for the diameter of the body of the muffler, not the tip.

 

Thats kinda what I’m thinking too. The muffler I got was 4” so I exchanged it for a 5” muffler. Hopefully that works out better

 

I don't have measurements, but my old one was probably around 6" in diameter from memory

 

yeah looking at pics that sounds about right cause it looks like it’s got an inch of space all the way around the exhaust pipe. The math part of my brain apparently wasn’t working when making this decision

 

If it wasn't so late and wasn't snowing currently, I'd go outside and get some measurements for you! Maybe tomorrow if I can!

 

The 5 inch muffler came in today. Definitely too small in outer diameter, although better than the 4”. I sent it back and ordered the 6” magnaflow muffler and that will be the one for sure. This is gonna be way better than the ISR and look just as cool, or cooler!

^This looks about right for the muffler placement. Maybe slightly more to the left and angled slightly upward as it goes toward the tailpipe. Also will have the tailpipe exit at a slight angle to the right as well instead of straight out.



I’m gonna probably have them cut the tailpipe where the red line is and on kind of an angle as well.

 

Aye, sorry for the late reply. But I do think you'll be fine with the 6" muffler.

As everyone mentioned 4" Tip:


And while the measurement isn't perfect since it's kind of hard to do with one hand measuring and one hand taking photos and I'm measuring below the weld line, I'd say it's roughly between 3/4" to 1" for the outer body:

 

hey if you don’t mind would you measure the length of the muffler itself. Not including any piping, just the body of the muffler. I believe it’s around 14” and I read that somewhere before but I can’t find where. So just to confirm before I buy the wrong muffler for the 3rd time lol

 

Actually if you could taj a few different pics of how the exhaust looks and sits under the trunk like that I would be so grateful. There’s not a whole lot of pics online of this exhaust mounted in the car so a few different angles would help out a lot!

 

This all I got for ya:



Do note that this is for the NB, so the routing may be slightly different. The length of the body of the muffler measured 14"

 

Thanks man, that is the most informative pic I’ve seen so far of this exhaust. Got a bunch of important stuff there. I know the NB one is slightly different but not by much. My muffler will arrive tomorrow and I’ll get to do some mock ups. It might not be exactly the same, if I see something I might tweak and make it look better I will. But overall love the look of that exhaust

 

Got the muffler finished up yesterday. I’m going to take the car to a shop next week to have the 4” pipe put on, my friend doesn’t have the right equipment to make precision cuts that are aesthetically pleasing and I want it to be perfect there. For now we welded on a 3” tailpipe to the exit pipe on the muffler. Couldn’t have asked for better positioning for the muffler. It’s perfect. 3” ISR exhaust
the magnaflow muffler is so quiet it almost sounds stock