well on my turbo setup i am gonna be running a straight pipe right out the side of my front bumper from the turbo. so . if i can get away with using only one of my 02 sensors in it i would like to . since there will be no cat or anything the 2nd o2 would read same as the first making it useless. but my question is if i just put one 02 in the pipe and dont hook up the other one will my ecu go into limp mode or anything? also if i must use both how can i "fool" the 2nd one into seeing a diff ratio? its on my 97 RS.

if you dont use the 2nd one, you will only get a cel that will not effect your motor in anyway. its just a warning light to let you know your rear o2 sensor is going bad, nothing more. fuel maps aren't based on the rear one. you can do the mod to stop the cel, but it isn't needed.

ok cool . so just one ill use then . as long as like u say it wont hurt performance. but also then what about the wires for it? should i just leave them alone or do i have to splice the wires for the first o2 and connect them to the 2nd 02 wires also.

Originally posted by tim97rs
if you dont use the 2nd one, you will only get a cel that will not effect your motor in anyway. its just a warning light to let you know your rear o2 sensor is going bad, nothing more. fuel maps aren't based on the rear one. you can do the mod to stop the cel, but it isn't needed.

The rear O2 can do more than you think. If you aren't going to use it, I would look for a simulator to use.

Also I would doubt check, but I don't believe that a front exhaust exit out the bumper is NHRA legal. Something to look into if you plan on going to a track with strict tech inspection.



Exile Racing Technologies: http://www.exileracing.com
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so what else does the rear 02 do then ? also . i dont care for the track . i may try it once but i just doing it to have a faster daily driver. ha i know my side pipe aint legal but where i live the police got much more to worry about than that. also i leavin my muffler on the back mounted so it looks like ill still be usin it.

rear 02 tripping a cel means the cat's gone bad. This will affect your fuel mileage. It's gonna suck. My rear 02 is broken and I'm too lazy to pay 120 bucks for one, so I'm gonna wait. In the mean time my fuel mileage sucks big time.

i have a test pipe, and my rear O2 sensor has never gone off once, yet.... :P

I also have a testpipe and my rear o2 sensor hasn't tripped a code, oh yeah, it's not even plugged in. :)

it is my understanding (and this could be flawed) that the front sensor is the only one that will affect your ratios and fuel mileage. the rear sensor is there strictly to make sure your CAT is functioning properly. it is my understanding that the rear sensor has no bearing on your ratios or fuel mileage. thats why (id assume) when your cat goes bad you get a CEL for it, and thus informs you or the tech that its time for it to be changed.

Originally posted by 96eclipse2nr
it is my understanding (and this could be flawed) that the front sensor is the only one that will affect your ratios and fuel mileage. the rear sensor is there strictly to make sure your CAT is functioning properly. it is my understanding that the rear sensor has no bearing on your ratios or fuel mileage. thats why (id assume) when your cat goes bad you get a CEL for it, and thus informs you or the tech that its time for it to be changed.

correcto, except for the fact that the rear 02 will do something when it sences the cat has taken a shit. It will pull timing, This has been dyno proven by hrc. But it wont really hurt fuel performance. That is all taken care of by the upstream 02.

Nick
97RS


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Originally posted by Collente

Originally posted by 96eclipse2nr it is my understanding (and this could be flawed) that the front sensor is the only one that will affect your ratios and fuel mileage. the rear sensor is there strictly to make sure your CAT is functioning properly. it is my understanding that the rear sensor has no bearing on your ratios or fuel mileage. thats why (id assume) when your cat goes bad you get a CEL for it, and thus informs you or the tech that its time for it to be changed.

...It will pull timing, This has been dyno proven by hrc. But it wont really hurt fuel performance. That is all taken care of by the upstream 02.

reeeally? i never heard that. good info nick.

Originally posted by 96eclipse2nr
reeeally? i never heard that. good info nick.

Yes. Removing the rear o2 is bad.

Whatever you do just put in two bungs for them, no big deal. Bungs are like $5.

Edit: Hehhehehyhuehehe.. I said Bung.

I have a test pipe and it set off a CEL for my rear o2 sensor. I just soldered in a resistor and took care of it.