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running without cats..

  #1  
Old 09-20-2010, 02:56 PM
1st Gear
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Join Date: Aug 2010
Location: Louisville, KY
Posts: 18
Default running without cats..

what codes will i get if i run my a6 2.7t with no cats? will it effect driveabillty or just give me a check engine light?
 
  #2  
Old 09-20-2010, 08:36 PM
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Join Date: Jan 2010
Location: Denver
Posts: 772
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if you run without the front o2 sensors the ecu will default to backup tables which are rich and it will run rough. If you run without rear cats it will through a CEL, but wont effect performance as they only deal with emissions.
 
  #3  
Old 09-21-2010, 05:14 AM
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Location: Louisville, KY
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im leavin the front o2 sensors in, just gutting the pre cats. i guess its called piggies?
 
  #4  
Old 09-21-2010, 12:43 PM
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Location: Denver
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If you want to run piggies properly you need to relocate the front sensors behind the main cats. There is lots of information on this if you search.
 
  #5  
Old 09-22-2010, 04:20 PM
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Location: Louisville, KY
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ive searched quite a bit, and found a thread on making piggies, i didnt see anything on relocating the front o2 sensors. From what ive seen most people are using spark plug defowlers on the main o2 sensors. whats the purpose of relocating the front o2s??
 
  #6  
Old 09-22-2010, 06:12 PM
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Location: Denver
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then you aren't looking in the right places. You can run defoulers and it seems some people dog get any codes but proper piggies have relocated 02 sensors. You relocate them so they get proper readings of post cat concentration
 
  #7  
Old 09-24-2010, 04:30 PM
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Location: Louisville, KY
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i see. Do you know the best place to relocate them too?
 
  #8  
Old 09-25-2010, 05:37 PM
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Location: Denver
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somewhere right behind the main cats. You should be able to find a picture of the right spot if you search.
 
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