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Discussion Starter · #1 · (Edited)
so heres the thing...like our cars and my max the primary 02 sensors read a/f ratio and the secondary read that the precats are ok...so when we get header(s) we put the spacers in and trick the ecu and have no codes..... but on the newer cars i heard that the primary and secondary 02s read a/f b4 and after the cat...is that true? and if it is anyway to bypass that secondary 02 sensor to run catless in the headers???? me and my friend who owns a 09 maxima are trying to bypass the secondary sensors to run a full catless exhaust and see what full gains that motor can have...but thats the only thing holding us back..
 

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what about just getting one of those o2 simulators?
 

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Discussion Starter · #6 ·
If thats true then wont you have like 6 O2 sensors, 1 in each manifold and one after the cat, plus the emisions one?
no still 4 lol 2 b4 the cats and 2 after

what about just getting one of those o2 simulators?
wont work because the secondary 02s read a/f ratio also

Why are you so worried about the check engine light? The engine should still run fine even if it thinks the cats disintegrated....:crazy:
because the check engine light always on sucks and u wont kno if anything else is wrong because u think its just for the 02s
 

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Mike the second ones are till O2 sensors, one if them is the same part number rear sensor used on the GT-R, 3.5 Altimas, 3.5 Altima coupes, the opposite one is the same part number as the B16 Sentras, 3.5 Altimas, 3.5 Altima coupes, and the Rogue. Doesn't say which bank takes which one though, that depends on Cali or Fed emissions, either way, they, from my knowledge and word around the shop is are just common O2 sensors for emissions purposes....
Find me a viable source where it says they are rear A/F sensors.....
 

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Discussion Starter · #9 ·
see i was telling everyone that but all im hearing all over the maxima sites that 06-08 maximas and 09-10 maximas secondarie 02 sensors also read a/f ratio and thats why they cant be spaced out to trick the computer
 

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It seems as if the only sure way is to try it all the avenues.

1. Try a simulator.
2. Do the spacing.
3. Keep one cat and put the sensor behind it. ( That way you will be able to see if having a cat decreases your hp )

Let us know how it turns out. And on another note, before I did my o2 spacing and my light was on, I lost 7mpg as my car was running richer than usual.
 

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Discussion Starter · #11 ·
^^ me and this kid are talkin he gotta get custom piping made to delet the cat in the header...so if anything doesnt work we can bolt the stock cat back into place
 

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Never heard of the second pair of sensors being A/F ratio sensors, the second pair just compare readings to the 1st two so adding the O2 spacers would simply increase the difference in the readings-- keeping the SES off when done properly. Try it.
 

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I'm pretty sure the B16 guys are spacing their two rear o2 sensors.

My sister drives an 05 Galant, and she had the cat code. They run four o2 sensors, so I just tried spacing the rear ones and the code was gone. It's worth a shot to try spacing it out first.



 

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I'd say f*ck it and just run a high flow cat (or two if you have a true dual setup). The power difference between a high flow and test pipe is like 1-2whp on an I4 (n/a), so I doubt you'll see less than 5whp difference MAX on your V6.
 

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Discussion Starter · #17 ·
^^ well now the kid doesnt kno if he wants to do it.... man i hatee when people dont try shit...then sum1 else will do it and heil be a baby about it lmao
 
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