View original topic: Cat and muffler orientation?
Crughy Sat Aug 22, 2009 11:07 am

Hi there!

2.1 van.
I am about to install my new exhaust. I just want to make sure:
I got a Bosal muffler. I can not see any orientation to it.
One side has the flange a bit further out than the other. On my current exhaust, the "in" flange, on the left, is further out. Should I assume it's the same thing. There is no way to tell. no marks or anything.
The muffler is engraved with the brand and part # or so. But that's it.
If I mount the way I think it goes. The reading is backward.

For the cat, I assume, the o2 sensor is on the left ("in" side). as on my current one.

I just realized I may have my answer in the Bentley, but as the muffler is not exactly OEM, any input may be useful to avoid doing it twice...


Vanagon Nut Sat Aug 22, 2009 2:00 pm

AFAIK, the O2 sensor is always "pre cat". So with that in mind, exhaust goes into pre cat side, (O2 bung end) then out to muffler. Consider putting antiseize on O2 sensor threads.

Got Bentley? :)

It shows cat/muffler on P26.10. *might* help with muffler orientation though you're using aftermarket. I too used aftermarket. Walker. IIRC, it had an arrow on it somewhere showing flow direction.


Crughy Sat Aug 22, 2009 4:27 pm

Thanks Neil.

I am battling with the rust right now... THe exhaust is out .
But the 02 is still in, and the 3 bolts holding the J pipe flange to the main manifold is still there...

I am going to get a torch... not other way out here... and an o2 sensor too I think...

Bloody rust!

I am going to check with my friend vendor. The Bosal pipe seems symetric inside. I can not see any arrow or anything...


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