BoidMorphs

When I last had my car tuned a probe was put into the left rear tailpipe and a flexible hose put over the tail pipe. When I bought a Bassani X pipe there were two bungs present up towards the front with one on each leg. Since the X pipe was meant to slide on just after the existing cats all four O2 sensors were spoken for. I asked Bassani why they put bungs in the X pipe and was told these were specially put in for tuners to attach their equipment for O2 readings. This sounded like a better way to read A/F ratios using the bungs because the readings would be closer to the engine and therecould be no leakage. By placing a probe in the rear of the exhaust I would think air could get in from the loosely fitted flexhaust hose and any readings are much furthur back and not real time. Does anyone here have any opinions or better yet, expertise on this they'd like to share?
When I get my car dynoed next time around I'm going to have off road headers installed so I'm thinking since there are no cats the second set of bungs can be used for the tuners equipment and the car's rear O2 sensors would be turned off via the SCT.

hawgman

You will get a far better reading with a wideband device in one of the bungs than you ever will with a sniffer.

BoidMorphs

That's what I thought. I'll make sure my tuner sets it up that way. The last time was a dyno day and I think he was more rushed to do everyone's car using the sniffer.