MPR

Vehicle: 00-SiR

Background:
I'm going to be building a custom full 2.5" exhaust system for it, from the header-back (including the header) to get it ready for cams etc.

My question:

The stock cat on the 00 SiR has an O2 sensor in the center of it. If I go to a high-flow cat, some have the O2 bung at one end of the cat (the exit end I assume). Will this type work on the SiR or will it throw a code? Or do I need a high flow cat with the O2 in the center of the cat like the factory setup?

Thanks.

JLCivixHBDX

When you are using a high flow cat in obd2a or obd2b, the secondairy O2 sensor is coding in 90 % of the time.

I find a solution, i use a bypass O2 sensor mounted in the bung of the catalysor if you have the bung.



or a Vibrant 90 degres bung (welding needed)

http://vibrantperformance.com/catalo...adfd70fa029d9e

good luck

MPR

Do these by-pass O2 sensors actually work? I don't think I'd trust them because the ECU is not receiving the proper signal.

Wouldn't it just be easier to use the stock O2 on a high-flow cat that already has a center mounted O2 bung?

And will mounting the O2 at the exit of a high-flow cat throw a code?

JLCivixHBDX

Hi,

In Obd2 the second O2 sensor have a simple function, watching if the catalysor is not blocked...and work properly, that all.

When you change the stock cat for a high flow, the restriction is changing, that's the reason why the ecu is coding, with the addition of the bung the flow is rectricted again in the input of the O2 sensor (smaller hole) and the ecu don't send a alarm.

You still use the stock O2 sensor before the cat and after you use the bung + the O2 sensor. And it's is working very well.

The first O2 sensor is very important for the ecu, the sensor send a signal for the control of the motor, but the second O2 sensor is use fonly for an alarm only, if the cat is jammed or open.


Good luck

MPR

Ok, I think I understand now.

Awsome.

Thanks.