subie thread v2: running full 3" turbo back with no cat, cel, issues?
04-27-2008, 03:11 PM
#21
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Join Date: Jan 2005
Posts: 2,877
Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
it wont always throw a cel, but chances are it will. we have a few customers running no cat on their MS3's and havent got a cel.
if you get a cel and need to pass emmisions clear the code and pray
if you get a cel and need to pass emmisions clear the code and pray
04-27-2008, 05:28 PM
#22
1.5 BAR
Join Date: Oct 2005
Posts: 1,490
Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
Originally Posted by ichbinsobose
how would your car know you have a cat
it has a 02 sensor after the kat and one before.. so ya taht obd2 ---- is getting too smart
04-27-2008, 05:34 PM
#23
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Join Date: May 2003
Posts: 6,279
Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
You WILL get a secondary O2 cel.
Those ebay adapter/resistor will not clear it on a SUE-BE, I remember reading some homemade ---- online that you will need a resistor and a MFD Cap to get rid of it . JUst look on line I sure there are tons of info.
Those ebay adapter/resistor will not clear it on a SUE-BE, I remember reading some homemade ---- online that you will need a resistor and a MFD Cap to get rid of it . JUst look on line I sure there are tons of info.
04-27-2008, 06:28 PM
#24
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Join Date: Apr 2006
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Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
it's not the resistor mod that works for the o2. it's the fact that too much exhaust heat is hitting the sensor, causing it to read fucked. sparkplug arrestors move it away from the heat, letting it work in cooler temps, accurately.
04-27-2008, 07:10 PM
#25
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Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
Originally Posted by c0mpl3x
it's not the resistor mod that works for the o2. it's the fact that too much exhaust heat is hitting the sensor, causing it to read fucked. sparkplug arrestors move it away from the heat, letting it work in cooler temps, accurately.
wrong as well, to check the operation of the cat the ECu alters your air fuel while cruising and expects a certain AFR after the cat. if it doesnt see these conditions it thinks the cat is fucked.
04-27-2008, 08:27 PM
#26
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Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
Originally Posted by Racintweek
wrong as well, to check the operation of the cat the ECu alters your air fuel while cruising and expects a certain AFR after the cat. if it doesnt see these conditions it thinks the cat is fucked.
04-27-2008, 08:57 PM
#27
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Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
like i said in my earlier post, you arent garunteed to get a cel, certain ecu's are more sensative than others but all OBD2b and later emission controls have this feature. if you were to get a cel because of no cat that is why
04-27-2008, 09:17 PM
#28
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Join Date: Aug 2003
Location: NE-PA
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Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
You guys are making this ---- way too complicated lol. I have an Evo and WRX and all I have is the auto parts store spark plug anti-foulers on the rear o2 sensors to move them out of the exhaust stream. No cels and no cats. 
The rear sensor looks for a voltage difference as compared to the front one, so as long as it's out of the main exhaust stream you're ok. No, it doesn't really ---- with afr's during cruise or full throttle, but then again WRX's are pig rich from the factory. The one in the up-pipe you're thinking about is an egt probe. If you haven't done an up-pipe yet I highly recommend it, especially if you think the turbo-back pipework made a difference...plus there's another highly restrictive cat in the up-pipe section. 
The rear sensor looks for a voltage difference as compared to the front one, so as long as it's out of the main exhaust stream you're ok. No, it doesn't really ---- with afr's during cruise or full throttle, but then again WRX's are pig rich from the factory. The one in the up-pipe you're thinking about is an egt probe. If you haven't done an up-pipe yet I highly recommend it, especially if you think the turbo-back pipework made a difference...plus there's another highly restrictive cat in the up-pipe section.
04-27-2008, 09:55 PM
#30
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Join Date: Apr 2006
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Re: subie thread v2: running full 3" turbo back with no cat, cel, issues?
Originally Posted by slo_crx1
You guys are making this ---- way too complicated lol. I have an Evo and WRX and all I have is the auto parts store spark plug anti-foulers on the rear o2 sensors to move them out of the exhaust stream. No cels and no cats. The rear sensor looks for a voltage difference as compared to the front one, so as long as it's out of the main exhaust stream you're ok. No, it doesn't really ---- with afr's during cruise or full throttle, but then again WRX's are pig rich from the factory. The one in the up-pipe you're thinking about is an egt probe. If you haven't done an up-pipe yet I highly recommend it, especially if you think the turbo-back pipework made a difference...plus there's another highly restrictive cat in the up-pipe section.
The rear sensor looks for a voltage difference as compared to the front one, so as long as it's out of the main exhaust stream you're ok. No, it doesn't really ---- with afr's during cruise or full throttle, but then again WRX's are pig rich from the factory. The one in the up-pipe you're thinking about is an egt probe. If you haven't done an up-pipe yet I highly recommend it, especially if you think the turbo-back pipework made a difference...plus there's another highly restrictive cat in the up-pipe section. 
