Ok, everyone knows that my O2 sensor is after my cat. I have seen many people with an Si run no exhaust at the track w/a turbo kit. How does this not throw a closed loop CEL if you take the exhaust off? The O2 sensor has nothing to read.

 

They're taking it off after the cat.

 

Thanks for the bullitin from the department of the obvious. I know that, LOL. I just want to know how it doesn't trip the CEL into closed loop mode.

 

Because the O2 sensors are in the cat, not the exhaust like mister "obvious" said.

Dustin

 

Isn't the O2 sensor after the cat?

 

master of bation I suggest you enlighten yourself and get under your car and look for yourself if you dont believe us.

 

No.

 

my 00 Si has one pre-cat, and one IN the cat.......right now i am running open downpipe with my secondary (In cat sensor) wrapped up in foil......no problems thus far

 

Just run the car with no 2nd O2 sensor. It's only there for emissions. It won't rob power or anything. Your CEL will be on, but who cares if you're running open exhaust anyway....