My uppipe and downpipe are getting fabbed for my RS-T and should be done very soon and I'm having my wastegate dump to atmosphere instead of return to the downpipe. Since I have a 98 my front 02 sensor is narrow band and I tapped that for my A/F readings. Obviously I'm going to have the bung welded before the wastegate dump but I have a few questions...

First, will having the 02 before the turbo have any impact on the front sensor or its readings.

Second, since the second 02 will be reading after the wastegate dump does anyone think this could cause problems when running in closed loop, or isn't the rear 02 factored in for corrections(intuitively I think it would richen things up a little because it will read significantly lower 02 levels but then again maybe it's only there for OBD purposes)

Third, is dump going to be a severe PITA for tuning on a Link for similar reasons as question #2


Sorry for all the questions, I've just been wondering about this goofy setup.

Thanks,
Brian

the only real concern Ive had with open dumps, other than the local popo not liking it. Is that you cant hear det when its going, its just louder than everything and covers it all up

open O2 housings sound AWEASOME. I have one on my 95 eclipse and people are scared when they hear it. Literally, its so loud it can rattle the fillings out of my teeth.

For some wideband sensors having the sensor pre-turbo will throw off readings quite a bit. It's the high pressure that will make the sensor tell you your rich when your really not.

O2 sensors should always go post turbo and at the minimum of 8" after the turbo.

Your narrow band o2 sensor wasn't accurate to begin with...

The close you put it to the heat source (exhaust valves), the hotter it's going to get. All o2 sensors have a certain operating temp range, and you can overheat them. They'll indicate a higher lambda value when too hot.

As for the wastegate dump throwing off closed loop o2 readings... You won't be closed loop *and* have an open wastegate all that often. All depends on the ecu you're using, when you go into/out of closed loop EGO feedback.