exhaust/cat matching question.

[Slipp]

Hello! I've a 08 SI Coupe.

I want to do an exhaust job on my civic. i live in GA and each year i have to pass emissions test.

I have looked as some high flow cats but they seem expensive when combined with the cost of header and cat back exhaust.

I have decided on a combo of parts, i would like some opinions as for as fit and stuff goes...

i was thinking... DC race Header (since the header goes down pass where the stock cat is) from there runn a cat back GReedy SP2 (im going with SP2 b/c they claim is one of the quieter high performance exhausts) and somewhere in line on the cat back, install this: Honda Civic MagnaFlow Spun Metallic High-Flow Catalytic Converter at PRO Civic.com

The SP2 is 60mm dia which is 2.36"
I can get that highflow cat in 2.5"

i have never seen the underside of my civic. Will there be a space to install this cat inline on the catback exhaust? And how well do you guys think this will work? Anyone have any experience with this cat, im curious how it will modify the sound.

If anyone has other opinions on what i could do with out spending an extra $350 on a highflow cat - im open to ideas.

Btw hello everyone, im a new civic owner and new to these forums!

[firstsi]

good question im considering a similar set up but with the stock header
and using a mgna flow muffler all in 3"

[corza]

You can do that, there is plenty of space to work it out. However IF you want to have your O2 sensors installed into the cat you will need to lengthen the wiring for the sensors. Additionally you will need to do some cutting and welding and may want to install an additional hanger.
Since you are trying to get a setup that will pass emissions but give you a nice flowing exhaust without being too loud and do it at a reasonable cost the following is an option that has worked well for me. Honda has a factory header on the car when it leaves the Plant, granted it is the not the most open/best tuned header but a header none the less. So I decided to leave the factory header in place and replace the cat with a Random Technology cat. I replaced the factory catback with an aftermarket catback (Vibrant StreetPower). Everything bolted up easily and the O2 sensors plug right into the cat and are functioning normaly with no cell. The total cost was about $875. I will likely install a Comptech shorty header at a later date but I'm happy with the current setup and it will pass the emisions test.
Just another option to consider.

[Slipp]

Ahh excellent, thank you for you input.

Leaving the stock header will definatelly be an eaiser install, it seems; and i could, like you, install a aftermarket header later down the road.

I like this option.

Thanks!

[Tschuess]

Regarding locating your cat somewhere else in the exhaust system, I read on the Random Technology website that the cat must be placed in the original location to be considered legal. Look at the bottom of this web page.

Converter Installation Guidelines

[iomatic]

Vibrant with cat?