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Discussion Starter #1
i want to tune and pull one factory upstrem o2 and use that bung for for a wide band tune my wot fuel mixture and put factory o2 back in when done. will this work or will car run like crap just reading off of one bank?
 

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i want to tune and pull one factory upstrem o2 and use that bung for for a wide band tune my wot fuel mixture and put factory o2 back in when done. will this work or will car run like crap just reading off of one bank?
Car won't run right with the upstream out.You will have to add a bung or use a downstream o2.(won't be as accurate)
 

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Discussion Starter #3
i know i should read upstrem data. welding a bung with mid pipe on car looked like a pain upstream of cat. wanted to take a short cut and remove 1 sensor just to tune and put it back when im done. i though it would work cause at wot its not running in closes loop.
 

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^^ What they all said.
 

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Something you *can* do: Get a wideband that has a 1V O2 simulated output, and splice that into the primary sensor wire that feeds back to the PCM. It should work. At least, it worked well for me on a 2000 Honda Prelude, and I ran it that way for several years, even passed CA smog with it on. It allows you to put the wideband sensor in place of the stock upstream sensor. You still have to leave the upstream sensor plugged into its electrical harness, otherwise you'll throw a trouble code for the O2 heater circuit failure. Personally, I wouldn't do something like this again, as my goal is to not cut a single damn wire on my Challenger. For the things I did to my Prelude, all fun, I had to hack alot into the wire harnesses. I'll never do that again.
 

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Discussion Starter #8
thanks guys for the input
 

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Aem sells a band clamp with a bung welded already all you do is drill a hole and your done
 

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Just use a rear o2 sensor bung. It is not too far back. Most dyno shops use a sniffer at the end of the tail-pipe and still get accurate readings. You dont need to tune to a specific air/fuel anyway. A good tuner can tune based on feedback from the engine. Some cars like 11.8 and some like 13.2, all that matters is that it is making power without knocking. Dont tune for a specific air/fuel or you will be leaving power on the table.
 

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Discussion Starter #11
andy how accurate is post cat readings compared to pre cat?
 

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Discussion Starter #12
Aem sells a band clamp with a bung welded already all you do is drill a hole and your done
i seen that out there but gotta fit a drill in there or i guess a 90 deg die grinder with a stubby bit. but i like welded bungs better.
 

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How accurate do you need it to be? You don't need to tune to a specific air/fuel. Tune it.to optimum performance and record what the air/fuel is and that is your baseline. Post cat is usually within .5 of pre cat air/fuel.
 

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Discussion Starter #14
i wanted to read a\f while i was tuning. i think if it was to lean it would surge and knock and rich would be flat and lose power. i have tuned plenty of holley 4150 and not used a wideband in the past, suck through, blow through and natural aspirated. im new to fuel injection tuning. had a turbo car and i had a wideband it was nice when you know how far you can turn boost up while watching a\f. i have been tuning with predator seat of pants.
 

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Use a rear o2 hung. Wont hurt anything. Im willing to bet that at idle and any closed loop operation it will stay right at 14.7:1. If so, its extremely accurate. At wot you should be around 12.0-12.8 if naturally aspirated and 11.3-12.0 if boosted.
 

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Discussion Starter #16
good info, will a 85mm tb cause much of a a\f change? thats the main reason i wanted to use a wideband.
 
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