87 carerra, smog-test with pre-muffler?

[jlewis5534]

i have an M&K pre-muffler on my 87 carerra and I am due to have car smogged. Anyone have any experience or advice with this. I'm not sure if it is worth getting car really hot and having it tested, or just to go ahead and install cat converter back in before. Any advise would be a big help.

[kidrock]

mixed bag of responses. Some have passed w/o the cat, some have failed.

I would change oil, air filter, adjust valves, connect brown wire @ DME and put in stock chip (if replaced). Drive until hot, test immediately.

YMMV

[Joe Bob]

pretest it.....

[mtb001]

depends where you are testing, I can't pass with bypass, have to install cat once every 2 years.

[James Brown]

You can get a cat and swap out the premuffler for the test.

[hangar21]

mtb001 is correct, it depends on what state you are being tested? My 87 is in Texas, 2011 test do NOT require emissons testing. I would check your state regs and have a pre-emissons check.

[vracer]

How big a deal is it to put the cat back on? (Not the cat-back ;>)

[Tigerrat]

9 bolts hold the cat or pre-muffler in place. Amount of rust/corrosion depends on how long between tests. I've had to do it every year here so not too bad. Ken

[Quicksilver]

Stainless bolts with copper nuts and the change isn't a big deal.

[kanadary]

in WA state i had to reconnect the o2 sensor wire, it was unplugged by the PO for some reason i don't know cause idle seems to still be good.

[Nine9six]

Originally Posted by Quicksilver

Stainless bolts with copper nuts and the change isn't a big deal.

...other than the $30 in cat & exhaust gaskets.

[cattman]

I, too, have an upcoming test here in ATL, and my plan was to put the original cat back on, for the test, and then put the bypass back on afterwards.

Is it necessary to remove my Wong chip for this brief period?

Must I use new gaskets, too?

[Joe Bob]

Depends on what your State decides on the limits. If as tough as CA, probably not. That's why it's recommended to pretest.

[Roc Doc]

It won't pass the visual test. The cat has to be in place.

I have a 76 that was originally sold in WA, so I have a nice Non-Catalyst sticker in the door jamb, so I can get my 3.2 to pass without the cat in place, but an '87 is going to have to use the cat.

[tratza]

I ran a bypass on my 1987 (well over 140,000 miles) and passed every year with room to spare until Houston TX began checking for NOx. Even with Daugherty cams I passed all but NOx. The mass air flow probably helped clean the exhaust. I'm guessing Atlanta is checking NOx.