Cat delete & O2 sensors?

[Timco]

Originally Posted by notech

Sorry, do I need to connect both of the sensors per pipe? cheers

If your car has them then you need them. It needs that feedback. Unplugging one will give CEL.

[notech]

Me again!
Yesterday I was changing spark plugs and found that manifolds don't have any cats!
My car is MY 03 and manifolds look pretty standard.
I am surprised, shoulnd't I have two cats on them?
Cheers

[Ranfurly66]

I have the same set up on my car - euro spec car, apparently EU4 emissions - has 2 cats at the rear just before the muffler box.

[notech]

Ok, that makes sense! so I am running with no cats then (the exhaust doesn't sound so loud as no cats at all, to me, still similar to stock at low rpm, then high ad 4K rpm of course).
I will try to put 2x O2 sensors on cat bypass and 2x O2 sensors out somewhere to pick clean air, that should fool ECU and remove CEL I believe.
Cheers,
Ser