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Question on catless downpipe

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Calgary, AB, Canada
#1
as the title states, this is an incredibly stupid question..... but if I'm running a catless DP, would my o2 sensor defouler go in the upstream sensor ( post turbo ) Or the downstream o2 sensor ( what would be post cat but is now just a hollow chamber ) ? Genuinely curious as i installed it in my upstream and my car SEEMS to be running okay, it even pops and bangs like usual HOWEVER, I do get randomly have a rough idle occur almost as if the car tries to stall out and the last time that happened it was my evap system ( which was fixed like 5,000, km ago ).

Did I done goofed?


Edit: I monitored the timing advance, afr and LTFT using the torque app, my AFRS used to fluctuate like crazy ( big ups and downs with huge difference between commanded and actual read ) but now they are holding steady even during WOT ( as in I dont see huge ups and down on my graphs unless I'm lifting or flooring it ). However I did notice while it was bogging down at idle and trying to stall it logged and AFR spike to almost 24. My timing advances even seemed to steady out as sometimes I was seeing as much as -10 at idle, now I only see as high as -3 or low whatever you wanna call it. My LTFT seems relatively more stable however I never noticed it go +/-7 at any point previously. I know I'm getting tuned soon im just tinkering with my car is all, but yeah.
 


Last edited:

TyphoonFiST

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#2
Down stream o2 sensor post cat.....for the love of God don't drive it anymore until you change it. This is a good way to Detonate and make your engine Lawn art!
 


OP
T
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Location
Calgary, AB, Canada
Thread Starter #3
Down stream o2 sensor post cat.....for the love of God don't drive it anymore until you change it. This is a good way to Detonate and make your engine Lawn art!

You know, I drove it for about 10km and she was popping more then usual so i instantly went back home, kindda figured I messed up hahah

Guess I'll be paying extra attention to my oil next time I change it. Thanks alot brotha you helped this dummy out big time haha
 


OP
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Thread Starter #5
Hopefully you didn't Trudeau the Engine.....[drummer]
😂😂 nice reference I like it, what damage do you think it could of done? Genuinely interested here, whats done is done so im kindda intrigued, how much damage could 10km of done? Honestly I dont think I did as I was monitoring timing adv on torque ( idk how accurate ) and i never noticed anything more then -5 where as before it was much higher which I found odd but yeah. Afr also was solid in the 14's at idle and cruising in the 20's which I've always been told is normal ( unless its not ) and I also monitored boost and didn't have any strange fluctuations at all, I was genuinely surprised.

Like I said the ONLY thing I noticed was that the AFR would go weird ( low 13's ) at a few stop lights causing it to bog down but it always bounced back up and held in the 14's again. STFT was ALL over the place but ive heard thats normal. LTFT was 1.6 at cruising and 4.7 at idle. Of course idk if any of these numbers are good but from what I've read those numbers aren't too bad?


Please feel free to correct me if I'm wrong as the more knowledge I have the better.
 


TyphoonFiST

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#6
Just don't drive it until you move the o2 sensor elbow to the Downstream o2 sensor. The car could lean out and that is when it will detonate and you create what others call a window to look inside your engine.
 


TyphoonFiST

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#7
Did this ever get remedied? Or did the motor have a NoNo?

Sent from my SM-N975U1 using Tapatalk
 


OP
T
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Location
Calgary, AB, Canada
Thread Starter #10
fwiw my car pops small flames through the stock catback, resonator and muffler with a catless downpipe

damn dude, i haven't gotten flames.... i don't think, now im jelly :( i get lots of pops when you lift after a hard pull... but no flames :(
 


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