Test Pipes Question.
 

Just got the factory cats off the car and only broke one Bolt on the Passenger side. The DIY helped alot to tackle those from the engine compartment first. Just needed $50 more in tools, but you can never have enough. :)

So the CNT test pipes are in my hand. I plan on putting the plug in the forward bung hole near the headers and using the extended tube near the middle for the O2 sensor. The hole inside drilled into the exhaust is only 1/4 diameter and not the full size of the bung hole threads (about 5/8").
Do I drill this out or leave it alone? I am not a mechanic, but pretend to be one on Father's day.
I can't wait to get that factory exhaust off the car!!!

I would put the O2 sensors where they were intended to go and not worry about drilling out the smaller holes. Were you just thinking of moving the O2 sensor further back hoping to not get any CEL? I don't think a few inches will make a difference.

If CEL comes on repeated due to the O2 sensors, AND if you plan on getting a dyno tune done after all your breather mods are in place, they can omit those sensors in the tune.

Thanks for your reply. No, I was not going to remove and reweld the tubes, but there was just a small hole for the o2 sensor. I am not sure how it all works or why there is an extended tube for the o2 sensors. Just a trick for EMS?
I also notice the factory Cats have a small extension of the exhaust that goes through the flange and there is a small collar the seals to the exhaust manifold. This is not on the test pipes. Do I need to make or purchase a gasket between them now?

I'm not entirely sure if I understand what you're getting at, but I'll give it a shot. From your original post, it seems that you're referring to the O2 sensor - does it NOT fit into the bung of your new test pipes? The extension off the pipes are both present to pull the O2 sensors back to prevent CEL. Less restriction and therefore more air flow - your car will throw a code. By the way, just a heads up...I had my test pipes on (with full exhaust) on for a little bit under a month. I pulled my plugs the day of prior to my UpRev tune. They were charred white (not completely, but getting to the point). Keep an eye on those plugs. Does that answer your question?

As for the other small extensions and such, you do NOT have to purchase anything to refit them; leave them off. The small collar seals that you're talking about about the OE ringed gaskets. You don't get gaskets when you throw on test pipes from anyone; they won't fit with OE headers. Purchase gasket maker (orange goo stuff); acts as a sealant.

By the way, did you get the forward bolts yourself (the one you broke)? I just paid $40 bucks to have both of them broken via my friend's dealership. Best $40, evveerr!

Thanks for the reply. If anyone know the manufacturer of the orange goo stuff let me know. I would like to get the car out of the garage as soon as possible without having to ramp/jack it up again.
Here is the picture of the bung hole with the small hole inside.
http://www.the370z.com/members/zeein...inside-why.jpg

inside:
http://www.the370z.com/members/zeein...ole-inside.jpg

Compared:

http://www.the370z.com/members/zeein...ipe-flange.jpg

There were no instructions with the exhaust and on the weekend, I doubt to get any answers from CNT. I was hoping to drive it tomorrow morning.

So far, I have to go out and get some bolts, nuts and gasket material. Anything else?

I know mine and a few others didn't have any sealant in place before bolting the HFCs on.

All HFCs no matter who manufactures it are virtually the same design. One hole is for the O2 sensor and the other is for an accessory sensor bung (sorry can't think of the name at the moment), and there should be a screw cap to keep that covered. Make sure that it is tightly sealed otherwise it'll rattle like crazy and eventually unscrew itself completely off.