I recently bought 2001 SE AE 5 speed that came with an aftermarket Y-pipe with O2 spacers. Since I’m keeping the Maxima until the wheels fall off, and I live in CA where the smog stations do a visual inspection my car would not pass the bi-annual smog check without going for under the table smog and that gets very expensive.

I decided to go with the MagnaFlow CA CARB compliant front and rear pre-cats since I was able to buy them on Ebay with a significant discount (damaged box) and I am happy to report that I was able to install them at home without having to cut/grind/weld anything. Also installed four brand new Denso O2 sensors, new gaskets and SS hardware.

There were only two issues:

-Magnaflow welded the rear section mounting bracket in the wrong spot, so I had to bend the bracket about 90 degrees to clear the underside of the car and allow the Y-pipe to line up with the main cat flange.

-The front pre-cat is rounder and fatter than the OEM pre-cat which makes tightening the 3 flange bolts and two 13mm nuts difficult since the access is very limited. I used a short stubby13mm open end wrench and even with that getting the rear two 13mm nuts was very difficult.

Took the car for a 1H drive around town and all emission monitors are already set


Fits well before final tightening

Had to bend this bracket 90 deg to clear

Not sure what brand the Y-pipe is

Happy that the previous owner didn't overtighten the bolts

New Denso O2 sensors from RockAuto

O2 spacers

Removed the front header heat shield and cooling fans for better access

Three 13 mm bolts and two 13 mm nuts secure the front pre cat to the header flange

Bank 1 flange

Main cat

MagnaFlow front pre cat is wider and fatter and this makes the bolt tightening more difficult due to limited access

Used short stubby 13 open end wrench

Flange before final tightening

Magnaflow part numbers for 2000-2001 Maxima CA CARB

 

gotta suck having inspection, and I noticed you mentioned bi annual, dam. I live in Florida and we have no inspections what so ever. only time a car is looked at is when they come from out of state and the title office checks to make sure the vin matches the out of state title. the first thing I did when I got my max was gut the cat and put the spacers on the downstream O2 sensors. out here anything goes but if a cop gets bored you may get stopped for exhaust being too loud.

 

Florida sounds like a perfect place to own and enjoy a modified Maxima! Cops in CA will pull you over if the exhaust is modified and make you rev the engine to about 4K RPM while they measure the sound levels, if the exhaust level exceeds 95 dbA, you get a state referee citation which means that the car has to be brought back to stock and then inspected by the state (which takes time and costs money). Don't get me started on the C.A.R.B stickers that they are trained on to look for when they check under the hood.

 

I remember a YouTube video talking about a guy with a Hyundai Elantra N that had a huge hassle over the stock track mode..

 

Yeah, I felt bad for the guy. He had to go through a lot of stress instead of enjoying his new car. Looks like Hyundai ended up buying the car back from him.

Final (most likely) update 4: Loud exhaust and smog citation : r/ElantraN (reddit.com)

 

so many pics of cats, I think I'm gonna be sick