I've been thinking it would be a lot easier to fine tune my Weber 45DCOE if I broke down and put in a couple of O2 sensor bungs for an Air/Fuel gauge.

However, I have the racing beat street port exhaust ( RX7 1975-1985: Exhaust - Complete Systems: Street Port Exhaust System - 79-85 12A - ) and the two pipes don't converge until a few inches before the muffler.

So which pipe do I weld in the O2 bung? And how far back? (I'd rather not drill into the stainless steel header)

I would think you'd want one in each, since a weber seems to tune one barrel for each rotor, but then how do I wire the two O2 sensors into one air fuel gauge?

 

So you are trying to tune the carb with o2 sensors not jets?

 

I just wanted an air fuel gauge as a secondary tool, I'm planning on supercharging in the future, and then it's going to be even trickier to tune.

 

Yeah that will be tough! What supercharger?

 

And what octane fuel are you trying to tune on?

 

if you must choose, then choose the rear rotor. however, you may want to consider working on a way to do both. and if i recall, i think the probe should be 12 to 18 inches from the port.