Borla headers and O2 sensors

[Creager]

Hey guys,

I recently bought a set of borla headers for my engine build project, and one thing has got my concern. My 92 has only one O2 sensor, which is positioned where the exhaust goes from two to one before the cats. The borla headers have two bungs for the O2 sensors positioned upstream before the transition from two to one (similar to how a 93-94 would be)

What should I do? Screw in plugs at the existing bungs and have a new bung welded in at the stock spot? Or do you think it would run fine if the O2 senor was in one of the existing spots?

Thank you.

 

[Creager]

I did some more searching and it appears some have run just one side without any ill side effects, i guess it would just kinda suck if the otherside started having problems. Yet if i suspected a problem i guess i could just move the O2 sensor to the side i think im having a problem with. I thought these things were calibrated for a certin distance to the cats to work properly? Anyone got any info on that?

I wanna keep things as stock as possible... Oxymoron?

 

[BrooklynBay]

The tremperature might change, but they are mounted behind the catalytic converter, so there can't be much of a difference.

 

[Creager]

I only got one, stock its mounted before the cat. So they are supposed to measure tempature? I guess i would want it in the stock location then.

 

[BrooklynBay]

They aren't measuring temperature, but the air/fuel ratio. The temperature does play a role on them, since the catalyst requires a specific operating temperature to work properly.

 

[Ronin8002]

I had the same 02 sensor question when I put on my JBA's...two bungs, one on each branch of the y pipe. I plugged the driver's side bung and used the passenger side bung for a while. Didn't hurt anything, but I changed it later when I put on the blower so that the bung was at the junction. Keep in mind that having it on only one branch of the Y only allows the computer to read 3 cylinders.....since you're upping compression I would plug both bungs on the y branches and have one welded where the factory bung should be. Might not make a difference but it made me feel better knowing the computer was getting a more realistic A/F reading. Won't cost much to do this change either.

 

[Creager]

Will the PCM make changes to the A/F ratio if the 02 sensor is only reading half of what it’s supposed to? I'm just making sure I'm not leaning out my new motor or anything, I want to squeak out as much power as possible at the dyno =)

Actually, if anything, the PCM would want to run the cylinders rich in this scenario, maybe?

 

[410Fortune]

Just plug them off and have an exhaust shop or friend install a single bung similar to your stock 91 location.

Or even better update your computer and wiring to the 93 style! hehehe