True dual exhaust with stock o2 sensor.
 

Hey guys and gals,

I am thinking about buying a true dual exhaust system from racing beat:
RX7 1986-1992: Exhaust - Complete Systems: Road Race Exhaust System - 86-88 RX-7 Non-turbo -

The only thing I am thinking is that in the o2 sensor would only be reading the air fuel mix off of one of the rotors, not both. In theory this would be bad, but in practice, does it really matter?

My other option would be to get a system with a collector and mount the o2 there. Will also be adding a bung for a wideband sensor.

Any opinions/advice? Also the main reason i'm interested in this exhaust is becuase of it's high build quality, and reasonable noise levels.

the o2 on a stock system is hardly used anyways so it really doesn't matter.
Now,If you were running the engine with a standalone and a wideband then that would be different.

Different hey? Well in the long run I do want to go standalone. Could you elaborate a little more? I like to plan things for the long run so I won't have to modify the exhaust later.

The stock ecu has a closed loop mode for cruising and light load situations. That's the only time the O2 sensor is used. You can do just as well well by tuning your standalone in open-loop mode compared to the stock closed loop logic.

Most widebands have a 0-1v output that mimics the stock O2 sensor. So you can just plug that into the stock ecu.

Just a general note, standalones on non-turbo engines are a pretty big investment for a relatively small gain. Most people that do it are limited by class rules for racing. To really exploit the standalone's potential, it should be paired with a turbo.

Edit: I forgot to include that radical NA port jobs (bridge and peripheral) require standalones as well.

I did some electrical work for a guy and he paid me with a tru dual system. I had the same question, so he just welded a bung on one side of the RB presilencer. Seems to do the job just fine. Had to run a lil longer wire tho. Thanks RXspeed, I didn't know that!