Hello i have a 98 civic lx 4 door and i want to replace the header/converter. i have that big ugly converter. i was thinking of buying an aftermarket header for an ex model and welding a bung for the o2 sensor on the top. my oem style converter has the o2 sensor on top. is this possible? and will i pass Illinois emissions? im assuming i would have to use cat on the bottom of my exhaust.
( i wanna get rid of this) below.

 

I'm not familiar with needing to pass emissions here in SC, but if the EX has the same emissions as an LX then you should be able to pass.

manifold from an Y8 (EX) or after market header same application, Y8 OE or OE replacement cat., Y8 B-pipe/mid-pipe or a flange and a welder.

you will need to reroute the wires for the O2 sensors. there should be enough length for the primary O2 if you pull the wires out of the loom. the secondary may or may not need some length added.

good upgrade for these motors. they just want to breathe.

 

Y8 exhaust manifold
Y8 A pipe
Y8 catalytic converter
Y8 B pipe
Y8 gaskets and hardware
Extend 02 sensor wires, the wires for the secondary 02 sensor will need to be
extended to reach the cat. converter now located under the vehicle.



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buy an ebay header for 92-00 civic. they have 2 o2 bungs, one is closer to the top where a factory d16z6 o2 is. The wires for the primary o2 on the d16y7 should reach this location just fine. like stated above, use a oe cat from a 96-00 EX and the B-pipe from a 96-00 (should also all be the same as 92-95 stuff). If the d16y8 cat has the o2 in it, run the secondary o2 in there, if not, run it into the bottom o2 bung on the header, right before the collector into the cat. however if you run that second o2 BEFORE a cat, you may throw a code. What I did on my 96 d16y7 turbo w/o cat was put a o2 bung cap bolt and just rested the secondary o2 on the tranny (zip-tied in place) with aluminum foil wrapped around it.. never had any CEL.

also, look into converting the stock d16y7 intake manifold to the d16y8 intake manifold if you haven't already.