kevin2012

I am not sure if my 1991 S4 has a cat, any comment pls?

dprantl

That looks like a muffler, not a cat. Hard to tell for sure without actually looking inside.

Dan
'91 928GT S/C 475hp/460lb.ft

terry gt

I would go with muffler too, not a stock set up

SeanR

Muffler, interesting set up.

Tom in Austin

Agree, the standard assembly that fits in that location is actually made up of two cats, welded together into a single unit, with pipes for air injection.

Curious now whether you have emissions testing where you live and if so, how it tests out with a muffler there ...

G8RB8

Stroke it and see if it purrs. If not it's a muffler.
Seriously though I've never seen a two into one cat.

Vilhuer

It can be stock if car was made for ROW places where unleaded wasn't available. Even last GTS could be bought with that muffler in places like Saudi-Arabia.

123quattro

That isn't a cat.

77tony

That's looks like a 2 into 2 muffler and they do make 2 into 1 cats. T

BRB-83-911SC

That looks exactly like the stock front muffler on my 84 Euro (2 in 2 out). Where are you located? It is probably stock if your car was originally speced as non-cat version.

James Bailey

All the early 928 cats are two into one.....very common for any V-8 with a single exhaust pipe...

davek9

It is a right hand drive

G8RB8

Now I've seen one. Thanks guys. I still think that's a muffler though.

James Bailey

Yes it is a Euro front muffler more of a resonator actually....common for Euro S cars two in two out no provision for an oxygen sensor.

PHIL928

My GTS has that setup. It's only a muffler, you also won't have an O2 sensor and therefore a little less performance.
Saudi Spec car just like Erkka said