Header Install For 99 Civic Lx

[DirtySwede]

Hi guys, been trolling the forums for a bit, but just registered so this is my first post. Go easy on me, I'd like to avoid this

I've got a 4-Door 99 Civic LX. I've already installed a Skunk2 cat-back exhaust. I'd like to finish the exhaust setup with a hi-flow cat, and a performance header. All the headers I can find online say that they are for the 99 EX model only. I spoke to a mechanic at a local performance shop, and he said that the reason performance headers are for EX only has to do with the placement of the O2 sensor. Can anyone verify this, and if so, do you know what modifications I would have to make to a performance header to get it to work with my car?

Also, and this is less important than my first question, what suggestions do you guys have as far as hi-flow cat's go?

[simplegreen]

all the fitmit is the same.. and you still have 2 o2 sensors.. if he's correct, worst case is that you'll have to exented your o2 sensor wires longer. NO biggie.

what i think the difference is, is the alignment of the header down pipe to the rest of the exhaust system

[Calesta]

The placement of the O2 sensor isn't really a big deal. The main thing you have to worry about is the integrated catalytic converter. On the LX and DX, the cat is actually part of the exhaust manifold. When you replace it with a header, you lose the cat. The EX has the cat after the exhaust manifold and laying underneath the car.

DX/LX exhaust manifold/cat



EX exhaust manifold



Exhaust (top B pipe and mid pipe are for DX/LX, lower is for EX)



The header will replace the exhaust manifold, cat and B pipe on your LX, but it will still bolt up to the stock exhaust piping. You'll have to modify the donut on the collector of the header (mating to the exhaust) because the collector exit on the EX manifold (and therefore the header) is larger than the DX/LX. If you want to keep the catalytic converter, you'll want to buy an EX exhaust piping system, go aftermarket, or chop yours to add one between the header and exhaust pipe.

O2 sensor placement is taken care of by extending your wires- just make sure that you have the sensors in the correct location. One goes in front of the cat, and one goes behind. Don't mix them up.

As for high-flow cats, the Catco and Carsound are both excellent units.