Straight Pipe To Catalytic Converter?

[DoubleYOOHZ]

Hello Z enthusiasts,

I have a question regarding purchasing and welding on a catalytic converter. My car is a 1977 Datsun 280z and sadly, the 30 year no smog program does not apply in California. Car is sitting Non-op and running beautifully (with some issues on the alternator not charging the battery). From the looks of it, from the exhaust manifold runs a straight pipe into the exhaust. This is a modified exhaust (i believe magna flow). To get my car smog ready (because I want to daily this car), would it be a simple fix of just cutting the straight pipe and welding on a catalytic converter? Do I have to worry about 02 sensors?

[rcb280z]

No 02 sensors needed. Just go to a local "reputable" muffler shop and have them install a cat for your car. I had to do the same thing when I moved back to Ca. It cost me, when I finally got around to taking it in, around $250. Is that all that's not smog legal on your 77? You can run headers if you want. Just make sure it has provisions for the egr tube. MSA sells one. It's what I installed on my 77.

[charliekwin]

Yup, was about $300 to have the cat in mine done last year.

I'm no expert, but I think headers are only smog legal if they have a CARB number, and AFAIK, there are no 280z headers that have been approved.  The person doing your smog check may not notice or care, but I'm pretty sure they'll fail you if they do.  Good job, California!

[rcb280z]

I've had my 77 smogged 3 different times by 3 different shops over the past 6 years and they looked at it and didn't say anything. They made sure the egr tube was connected to the header though, so.....

I don't know if there is a CARB number. Not one that I know of. Maybe most techs realize that the original manifold isn't available any longer?

[charliekwin]

I've had my 77 smogged 3 different times by 3 different shops over the past 6 years and they looked at it and didn't say anything. They made sure the egr tube was connected to the header though, so.....

I don't know if there is a CARB number. Not one that I know of. Maybe most techs realize that the original manifold isn't available any longer?

I bet most of them probably don't even know what the stock one looks like 

I had an aftermarket Y pipe in my old Maxima that was way more obviously a problem that headers on a Z would be, and that passed smog every time, too. Some techs looked at it more closely than others, but I always get the sense that many won't fail you unless you're give them no choice.

[DoubleYOOHZ]

@rcb280z - Thanks for the reply. I did more searching and it is believed that the 77 280z have o2 sensors located elsewhere than the exhaust lining. 

[rcb280z]

I would like to know where you found that info. It is NOT correct. Download a factory service manual. 02 sensors were not used until later on, like in the 1980's. For the Z car that is.

[Chickenman]

Rob is correct. Nissan never used an O2 sensor on any 280Z car.

The 280ZX is a different story. Those did have Narrow Band O2 sensors, but the 280ZX did not come out until 1979 and is a totally different car.

Edited July 17, 2016 by Chickenman