I'm looking at an o/r x pipe and I'm curious what has to be done to the factory emissions equipment. I'd want to swap the stock h-pipe on for emissions testing but I know some people have cut smog tubes, can I install the o/r pipe without permanently modifying the emissions equipment?
Off road x pipe question
- Thread starter ACSPONY
- Start date
If you're replacing the stock H-pipe, just leave the smog tube connected to the H-pipe and disconnect it from the rubber-hose end of it towards the "burp" valve (motor end of the smog tube). Then just pull the whole sha-bang out in one piece - it'll take a long of wrangling and cussing and maneuvering, but it can be done (a tall set of ramps or having it on a lift makes it a lot easier). No cutting necessary at all, no permanent modification involved. The smog pump is fine right where it's at, and you don't gain squat from deleting it, so leave it be.
Getting the stock H-pipe back up in there is a challenge, but do-able, also - just bolt it all back up into place when it comes to emissions time, and be sure to get the 2-year registration instead of the 1-year deal, if they have that available in your area ... unless you enjoy swapping exhausts frequently.
Getting the stock H-pipe back up in there is a challenge, but do-able, also - just bolt it all back up into place when it comes to emissions time, and be sure to get the 2-year registration instead of the 1-year deal, if they have that available in your area ... unless you enjoy swapping exhausts frequently.
The metal smog tube slips into the end of an L-shaped rubber hose at the front end. Just loosen the hose clamp from that end and wiggle the rubber hose part off. You may or may not have a bracket for the metal smog tube attached to a stud coming off the rear end of the exhaust manifold - if it's rusted, you're either going to have to fight it with a lot of PB Blaster and a mean wrench, or just hacksaw that stupid little bracket off of there.
The smog pump will still be feeding air to the crossover tube that goes to the back of both cylinder heads. There's a T-junction where that same tube connects with the L-shaped rubber tube that would otherwise lead down to your H-pipe's smog tube. That part will just blow air, umm ... into the air. It won't hurt anything - just sucking air in through the pump and blowing it back out at the hose end, no biggie.
Some X-pipes have the smog tube fitting, others don't. I don't see the logic in off-road X-pipes with a smog tube fitting - the cats are gone, WTF do you need to be pushing air into the exhaust AFTER the O2 sensors for? Just hammer the sucker shut, fold it over and/or JB Weld the end, and consider it the exhaust's belly-button.
The smog pump will still be feeding air to the crossover tube that goes to the back of both cylinder heads. There's a T-junction where that same tube connects with the L-shaped rubber tube that would otherwise lead down to your H-pipe's smog tube. That part will just blow air, umm ... into the air. It won't hurt anything - just sucking air in through the pump and blowing it back out at the hose end, no biggie.
Some X-pipes have the smog tube fitting, others don't. I don't see the logic in off-road X-pipes with a smog tube fitting - the cats are gone, WTF do you need to be pushing air into the exhaust AFTER the O2 sensors for? Just hammer the sucker shut, fold it over and/or JB Weld the end, and consider it the exhaust's belly-button.
Who's gonna be looking under your hood when you're driving, or running down the 1/4 mile?
Besides ... I don't trust my hood being open around anyone else but myself ... and Frankenstang...
Besides ... I don't trust my hood being open around anyone else but myself ... and Frankenstang...
blackened88lx
Active Member
i just recently did an o/r x on my car and basically did what Darkwriter said. But, the smog pump makes an annoying noise pumping into the engine bay that you can hear while driving, so I shortbelted it because it bothered me. My x had the fitting on it for the pipe, I just couldn't get them to mate up properly so decided not to use it. I sealed up the tube on the x with a piece of high temp rubber hose with a plug in the end of it so I can unplug it if need be somewhere down the road. 
Not sure why I'd have to. It doesn't get hot enough down there to melt the hose.
Not sure why I'd have to. It doesn't get hot enough down there to melt the hose.
Hmmm ... never noticed any kind of sound at all with any of the cars I've left it open on. Maybe your bypass valve was stuck open and blowing all of the air straight to the smog tube instead of the the back of the heads...?
If some ricer asks what that whistle is, tell 'em it's the canuder valve...
If some ricer asks what that whistle is, tell 'em it's the canuder valve...
grey5.0beast
Cookies should never be DUNKED!!!
I have an o/r h and I have the smog tube hooked up to it. It's easier than taking all that crap out and putting it back, I just swap out the H for the stock each year when emissions comes around.
When the H-pipe and smog tube can all come out together in one assembly, what difference does it make, anyway? Same as blackened88lx, I didn't want to piddle with trying to get that stupid smog tube to hook up to the off-road X-pipe, especially since the thing is always basically fused to the OEM H-pipe to a point where you almost have to destroy it to take it off.Either way, the concept's pretty much the same. Unbolt stock crap, bolt up good stuff; when emissions time comes, unbolt good stuff, bolt stock crap back on.
grey5.0beast
Cookies should never be DUNKED!!!
yeah but all that twisting is pointless, much easier to just unbolt the eight bolts for the H and loosen the one clamp on the smog tube. All in preference I guess.
