I have a 5.5 gen Max and getting to install the Cattman headers. The question I have is this: Do I need the secondary O2 sensors that are on the factory y-pipe? The Cattman y-pipe does not have the bung for the sensors and I don't want to pay the muffler shop to install the 2 bungs on the y-pipe if I do not need them. I know the primary ones that are on the front and rear manifolds are needed.

 

You will get a code unless you sim the secondaries. Or, while he is installing, just have him install two bungs, how much could that be....extra $20? Then get two anti-foulers and re-install the secondaries. Going ahead and installing the bungs and getting antifoulers is the cheaper route if you don't want a SES light.

Of course, I've grown fond of my SES light. I know why it's on, so to me it's just verification of my Super Exhaust System!

 

if your o2 sensors are good then you will not get a code... you do not need an o2 sim nor foulers to prevent getting a code... get the extra bungs and install all your o2 sensors

 

To avoid a code when you unplug secondaries you will need to SIM the secondaries OR weld bungs in the y-pipe. I would just weld bungs in the y-pipe....it'll probably be cheaper than buying a SIM, if you can find one. I dont like driving around with SES lights because you may think you know what it is but when if something else come in and you always assuming its just secondaries and its not you going to have problems. Also, I dont know where you live but we have yearly inspections and you cannot pass emission test with and SES light. I put a SIM on mine but the company no longer sell them. So have a shop weld some bungs in and call it a day.

 

About Sums it up.....

 

3SX offers the o2 sims. I have a dual control unit on it's way to me right now.

 

Those will work, but don't have the heater circuit capability built in. So, you have to keep your secondaries connected or you will get a heater circuit code.

What concerns me about their description is that they fail to indicate the heater issue. Rather, they say you must keep your secondaries because the sim still needs a sensor signal to modify. Naturally their install instructions contradict that.

Just wanted to ensure everyone was informed before a lot of people started buying these.