difference between o2 sensor in x-pipe vs in cat.

[bebbetufs]

What is the difference between the two sensors, and how does running without the cat and the corresponding sensor affect the engine?

[bebbetufs]

Or is the sensor in the cat a temperature sensor?
Is this a not a common sensor on US cars? My car is a Japanese import.
I would like to know if I can remove it when going to a high flow cat, or whether I need to have a bung welded to the new cat.

[krystar]

my acura had 2 sensors. one precat is wideband for the ECU to control AF. one postcat is narrowband to test emissions. guessing same kind of setup on the 951.

if u remove the second, it'll prob throw a code thinking the cat isn't working...which it isn't.

[bebbetufs]

I'm certain that none of them is a wideband as the DME can't handle wideband signals.

The x-pipe o2 sensor is a 3-wire heated sensor while the one in the cat is a single wire sensor.
Anyone?

[nzporsche944s2]

The sensor in the Cat is a temp sensor on the Jap Market cars only (Part # 951 606 019 00). No longer available from Porsche. This sensor is not linked to the DME as far as I know and only controls the "EX" light on the dash. If you are removing the cat then grounding that sensor wire should stop the blinking "EX" light on the dash

[bebbetufs]

Ta mate.
That clears things up and explains why nobody new about this sensor.

Btw.
I lived in Te Kauwhata for a year. You've got some amazing roads down there. Would have loved to have had my car back then, or maybe even a Subaru WRX...

[nzporsche944s2]

Yeah they are sweet roads. Funny you mention that because the last time I was out there in my S2 I had a WRX duelling with me. Mechanically I don't mind WRxs it's just the spotty, caps on backwards, sagging pants teenagers that are drawn to them that bothers me....
(let the flaming begin...lol)