O2 Sensor Placement?

Charlie M · 01-14-08, 08:42 PM

I have limited space on my exhaust collectors to mount an O2 sensor so I'm considering mounting it in the end face of the muffler. This end of the muffler is an open chamber. The baffles start 3 or 4" from this face. The lower photo shows where I hope to install the bung. Do you think this will work?

Thanks,
Charlie

chuck smith · 01-14-08, 08:52 PM

I do not think that would be accurate enough since it is so close to the outlet

J. Salmon · 01-14-08, 08:52 PM

Good question, as I am going EFI also. I thought that the O2 sensor performance was affected by exhaust temperature and distance from the manifold. If this is the case, won't you be way to far away? Can you ask the manufacturer of the EFI system?

Steve C · 01-14-08, 09:04 PM

Charlie,

Installations I have seen place the O@ in collector merge just befoore muffeler neck and good idea to put a bung in each so you can swap the sensor annd see ea bank if wanted.

Steve P2125

David Briggs · 01-15-08, 12:42 AM

I agree, I don't think that it will read correctly in the muffler.
I installed one in the collector, right side, just behind where the 4 tubes come together.
I had to file a small semi circle on the sleeve of the muffler to clear the bung but it seems to work fine.
Dave

Peter D · 01-15-08, 07:01 AM

Charlie, the guru who did the specs for my setup (all aimed at passing the emissions tests) insisted that the O2 sensors be at the back of the collectors. In the attached pic, you can just see the large nut welded onto the throat of the collector, just in front of the flange. Mine are pointed down/out at 45deg, but I reckon that you could do something similar - with the sensors horizontal (looks like that way would be easier for you to mount the welded nuts).

Kind Regards,

Peter D.

Charlie M · 01-15-08, 01:25 PM

I could put the bung in the collector. I'll either have to notch the muffler inlet tube or lose about 1/2" of pipe engagement over the collectors.

Thanks all for the input.

Charlie

MReid · 01-15-08, 01:49 PM

With a heated O2 sensor, your accuracy will not be too far off in that location. However, it looks like the wiring harness would be too close to the collector and could melt.

Cliff Beer · 01-16-08, 02:47 AM

Agree with Mark, with a three-wire 02 sensor it should read OK in that position in the muffler howeve it is desirable to have the sensor tip directly in the stream of the exhaust. The reason why the O2 sensors are typically locatd in the position they are (downstream of the collector but not too far downstream generally) is that they have to be upstream of the catalytic converter to get a proper reading but downstream of the exhaust manifold so as to no read off one single cylinder. Obviously, cats are quite upstream in the system to promote fast heat build up which in turn means the 02 sensor is even farther upstream.