Focus Fanatics Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
268 Posts
Discussion Starter #1 (Edited)
I am curious if anyone has mounted a wideband o2 sensor in the stock svt exhaust set-up. I have an svt header/cat/flex on my car and do not see any good place to mount another o2 bung. If I can't figure this out I will probably get an orp for tuning purposes and use my cat when not tuning... Any help would be appreciated.
 

·
Registered
Joined
·
268 Posts
Discussion Starter #3
After the cat? I am pretty sure that would throw off the readings. My rear o2 sensor is disabled already, but I would like to install a wideband upstream of the cat in order to get the most accurate readings. Somebody please chime in if I am wrong about a wideband sensor's accuracy after a cat (stock svt cat in this case.)
 

·
Registered
Joined
·
9,084 Posts
You could have an exhaust shop weld in a bung for probably $20 at the most.
 

·
I AM DA FOCI FANATIC
Joined
·
3,715 Posts
It must be before the cat for accurate reading.

Also the closer to exhaust ports more accurate the readings are.
 

·
Registered
Joined
·
268 Posts
Discussion Starter #6
I know I can get a bung welded in for cheap, I am just curious about physical location on the exhaust. There just isn't a whole lot of room after the header collects down to 1 pipe and before the cat.
 

·
I AM DA FOCI FANATIC
Joined
·
3,715 Posts
The best place is right after all 4 meet in the collector.
 

·
Registered
Joined
·
23 Posts
The rear second o2 sensor after the cat only monitors the efficiency of the converter.....the first o2 sensor is used for fuel control to let the computer know if the engine is running rich/lean. the best place to mount one is off the first o2 sensor or have one welded in like a couple other people said.
 

·
I AM DA FOCI FANATIC
Joined
·
3,715 Posts
After the cat the readings wil be off yes but not by much to make a huge difference.
If its off .1 its a big deal to me. I want the most accurate reading I can get. .1 could make the difference for a melted piston.

Also the delay for the A/F to be read since it takes time for the exhaust to flow that far. Its reading A/F that was at 5800rpm but by the time you see it now your at 6200 and by the time you see your lean you have a cloud of blue smoke behind you.

Do it right.
 

·
Registered
Joined
·
11,906 Posts
I'd use the 2nd O2 bung.... its not going to make any difference if its pre cat or post cat... and before any says it... not even in a turbo car.
 

·
FOCUS REVOLUTION
Joined
·
2,872 Posts
after the cat it won't show proper A/F as focus guy say u can put it closest to the cyl and that would be the best reading
 

·
omn-nom-nomnomnomnom
Joined
·
2,293 Posts
I was running mine in the rear o2 on my ORP, and I just added a metallic core HFC into the ORP.

I have not been able to see any change in the wideband. Still 10.2 @ wot and 14.9 on the interstate.

:p
 
1 - 15 of 15 Posts
Top