1 o2 sensor- how to make it work on a dual exhaust setup

[-Levi-]

Hey Everyone.

kinda weird question for those exhaust exports, I am going to break this down because there is a bit to it.

DETAILS-
my car is a 81 911 sc with a 3.6 engine from a 1995 porsche 911.
my car (with 95 3.6 engine) is running s-car-go race headers with a gt3rs muffler
the oem engine has 1 o2 sensor that collects data from both headers via a cross pipe that goes into the muffler (please see random google pic below, you can see the o2 sensor where the exhaust comes together)



my setup has no pipes that come together other than the muffler- please see random pic of the exhaust setup like mine)



THE QUESTION>
how do I get the stock o2 sensor to read the exhaust from both sides of the engine with my setup? do I cut the muffler and weld the sensor in? do I just run off one side? is there a kit to run two?

or- what options do I have? remember this is a obd1 engine- which is different from the 96-98 obd2 setups.


thanks Gents

[Fly911]

You use one O2 sensor in one of the headers, you don't need two. You assume that the A/F ratio is the same on both cylinder banks. I (and many others) have run this set up for years, and it works fine!

[tirwin]

I believe the early versions of the SSIs had an option for an O2 sensor bung. It was only on one bank just like Fly911 said.

I believe that is the most common approach. You want the O2 sensor as close to the exhaust ports as possible. There shouldn't be an a meaningful variance between the left and right bank anyway.

[Bill Verburg]

'95m is OBD1 and has only a single O sensor input, you could put the O sensor in the muffler and get the average of both banks but most of us just put it on one side .

Mine, w/ the o sensor bung on the left side bank


OBD 2 cars will have 4 inputs, 1 pre and 1 post cat on each side.

[faverymi]

I run left side 02 sensor to DME.

I run right side 02 sensor to AFM meter in dash

Works just fine

[wayner]

I put a bung in each header.

I only run one sensor but I have the option of switching it to the other header if I ever wanted to use it for trouble shooting or whatever.

So far I haven't figured out a reason to test the other side yet.

[911pcars]

Manufacturers recommend not locating a WB sensor too close to the exhaust port - for longevity purposes.

Sensor(s) located too far downstream might delay A/F readings and thus confuse accurate diagnosis.

One could install a WB sensor system that supports two wide band sensors, or two independent sensors (and two gauges). More info is better up to a point. For one off, experimental engines, a WB sensor near each exhaust port provides even more accurate cylinder-to-cylinder info.

Reminder. Installed O2 sensors must be connected to a working system less they become contaminated by exhaust byproducts.

Sherwood