WRX downpipe. 2nd o2 bung bung 'ok' for obd1 o2v/wideband?

[my3awds]

I have a modified WRX downpipe on my car. It has an O2 bung at (a:)the stock location after the pre-cat in the downpipe. Then there is the one I added for the o2 sensor (b:)before the cat, and I just blocked off the (a:)stock location. Since I will be using a wideband soon, will running the stock o2 sensor in the (a:)location, then installing the wideband sensor in the (b:)location cause any adverse effects?



The reason why I want to run it like this is because if the stock o2 sensor is AFTER the cat, it will slightly richen closed loop operation which can be easily fixed with the safc (theoretically). I guess I'm just unsure if having a restriction like a pre-cat will cause a serious change in readings for a narrowband sensor. If I put the wideband closer to the turbo and BEFORE the cat, I should get a better reading. Feesable?

Manny~

[vrg3]

You don't need both sensors. Most wideband setups have a "simulated narrow band" output that can be connected to the stock ECU.

The catalytic converter definitely affects the readings of the sensor. In fact, looking for those changes is how an OBD-II ECU can determine whether or not the cat is working correctly. It's not just a restriction; it's a chemical catalyst.

So, never put a sensor downstream of a cat except for the rear sensor that OBD-II ECUs require.

[sammydafish]

yeah, that stock o2 sensor bung on your downpips is the 2nd o2 sensor. The WRX's main o2 is on the up pipe. The spot you have marked as A: is of no use to you.

[my3awds]

Thanks guys. If the AEM UEGO wideband has a simiulated narrow band, there shouldn't be a need to have a new tap right? Guess I'll find out soon enough.

[vrg3]

A new tap?

[my3awds]

Nevermind. I was thinking I might have to have a new o2 bung tapped pre-cat to install the wideband. But since the UEGO can do a narrowband signal to the ecu, what I'll do is install the wideband sensor in the tap that I already have (b:)and just tune the car that way. Once it's tuned, I'll simply remove the wideband sensor and reinstall the stock o2 sensor. Makes sense now. I guess you would want to do it this way since I hear the wideband sensors don't last as long as standard sensors.

[sammydafish]

most widebands are Bosch or NTK sensors that come stock on almost every new car. They last pretty long. People kill them becasue they have stupidly untuned cars and bake them with piston mealting EGTs. Get your car in good tune and your sensor will last 100k+

[vrg3]

Right, exactly, you don't need to add another bung because the wideband can replace the narrowband sensor.

I agree with Junior. You don't need to switch back to the narrowband sensor. I run my wideband all the time. It's nice to be able to monitor things. Many wideband controllers also have some datalogger facilities, which can be useful if you're not using an aftermarket ECU.