Where to mount wideband O2 sensor.

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MileHighDart

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So doing some work on my exhaust after the 5.9 swap.
Adding an Innovate LC-1 air/fuel gauge.
The instructions say to mount the o2-sensor 24" back from the exhaust port, and then it says (collector).

So does it mean in the collector, 24" from the exhaust ports.
Or
24" back from where the collector bolts to the header? That seems pretty far back.

Pretty sure I've read of guys putting them in the collector right after the header, but thought I'd ask for opinions before I drill holes and weld the bung on.
Running Doug's headers and 2-1/2" pipe from there back.
 
I imagine they mean either collector or 24" if your running manifolds.

My Holley sniper gives me a clamp where I got to install it just after the collector unless I weld a bung in the exhaust. I was wonder if I could weld into X pipe which ain't to far after the collector so it could read both banks?
 
You want the O2 sensor in a spot in the exhaust where it won't get too hot (less than 900*F I think) but also where the exhaust isn't too cold. The O2 sensors are heated, but the closer they are to the correct temperature the more accurate they'll be and the less the sensor heater will have to work (don't run them unpowered in the exhaust at any time!). Further back in the pipe condensation can be more of an issue too, you don't want the sensor loading up. You're also supposed to mount them at an angle, again, so nothing liquid builds up on the sensor.

The other issue is the header flange. Ideally, you don't want your o2 sensor downstream from a potential leak that could throw off the readings. So, in the header collector a few inches ahead of the flange is probably ideal. But most folks don't want to weld a bung into their brand new coated header. I know I didn't. Mine ended up about 8" or so behind the header flange. You also have to contend with the length of the sensor harness, the angle on the sensor for clearance, and in my case, 4 speed shift linkage rods, big torsion bars, etc. So mine ended up just behind the shift rods, ahead of the crossmember, with the sensor harness going up the inside of the 4 speed hump and through with the LC1 under the driver's seat.

Seems to work well, I run the same innovate LC1 and Bosch O2 sensor. But mine is just for tuning and diagnostics, I run a carb so the sensor doesn't actually control anything.
 
I, too, put the O2 sensor in the collector, just after the flange, at the correct angle and used a High Performance FelPro collector gasket. It has worked very well all year.
Good Luck
 
Rather than cut into the header, I mounted mine in the reducer right after the collector flange. It works just fine.

Wideband.jpg
 
Any photos you guys might have would be great. I'm looking to install one pretty soon and running dual exhaust makes choosing a spot twice as fun.
 
I also put mine in the collector at about the 10 oclock position.
Before I installed it I found information showing pipe color that determined temperature inside the exhaust pipe.
Then installed the sensor in the supposed optimum heat range area of the collector.
(about 6 inches up from the flange.)
 
TrailBeast said:
Before I installed it I found information showing pipe color that determined temperature inside the exhaust pipe. Then installed the sensor in the supposed optimum heat range area of the collector.
(about 6 inches up from the flange.)
Click to expand...
that's how we used to decide where to put the crossover before all the pre-built pipe setups. rattle can the pipes down stream from the collector and see where it burned off the quickest :lol:
 
Tried not to reopen an old post. Well not that old.

I just installed new Dougs ceramic coated headers and do not want to cut the coating I spent hours protecting during install. So if I weld the bung in the collector adapter after the 3 bolt flange... what happened when I want to go open header? Ideally a 1” thick collector spacer Drilled for the wide band would work - unbolt the exhaust and rebolt the adapter but 1) does anyone make one and 2) would the O2 even do anything with it open header mounted that close to the edge of the open collector?
 
The O2 sensor would not be accurate mounted that close to the end of the open header. Even just mounting it downstream from the header flange creates the possibility that it could be influenced by a leak at the header gasket. I mounted mine downstream of the header flange anyway as I explained above, but it is a consideration.
 
If you run uncorked and dont run collector extensions you are giving away a ton of torque, and therefor horsepower.
I would get some 18"extensions and put a weld-in bung in them just like you are using in the reducer. I would put the bung a couple inches back of the flange, and make sure your collector gaskets are good.
 
Also if you want to save "a bit" of money and if you have access to a fasteners store, most O2 sensors are the same thread as an 18mm (Ford style) spark plug. I'd have to look that up. It is possible to order hex nuts this size, and they are a HELL of a lot cheaper that all the bungs everybody is selling.

And of course that points out ANOTHER little tidbit, which is, if for some reason you feel the need to run without a sensor...........18mm plugs are cheap LOL
 
33IMP said:
If you run uncorked and dont run collector extensions you are giving away a ton of torque, and therefor horsepower.
I would get some 18"extensions and put a weld-in bung in them just like you are using in the reducer. I would put the bung a couple inches back of the flange, and make sure your collector gaskets are good.
Click to expand...


That’s one reason why guys think their open headers cost them power. The collectors are too short when they unhook the exhaust.
 
yellow rose said:
Yes.
Click to expand...
Yep. Exactly. A point of having only a portion welded to the primaries allows for the different length extensions. For a basic 340 pipemax shows collector lengths around 20" are usually best overall. That's from the end of the primaries to the first interuption, whether that's an H a muffler or open.
 
Mine is right behind the header collector/reducer. Make sure it's above horizonal also. My personal experience is that the LC1 isn't that great, I switched to an AEM with the EFI and the car immediately ran like a million bucks with the automatic tuning running for a while.

upload_2020-9-1_19-57-0.png
 
Syleng1 said:
Tried not to reopen an old post. Well not that old.

I just installed new Dougs ceramic coated headers and do not want to cut the coating I spent hours protecting during install. So if I weld the bung in the collector adapter after the 3 bolt flange... what happened when I want to go open header? Ideally a 1” thick collector spacer Drilled for the wide band would work - unbolt the exhaust and rebolt the adapter but 1) does anyone make one and 2) would the O2 even do anything with it open header mounted that close to the edge of the open collector?
Click to expand...

Screenshot_20200829-160011_eBay.jpg
 
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