Si exhaust on R18 Civic (sedan)

jarvasdb1

jarvasdb1

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So I'm always careful about posting or what I say in my posts. I did some reading about a weak ago and came across threads that talked about Si factory exhaust systems and how they fit on non-Si's. I was shocked but also not surprised to have read that it wouldn't be a bolt on affair. I didn't question what I read since will hope whoever is giving advice would be based on fact/knowledge and not off of educated guesses. Being that I work for a Honda dealer and just swapped out my exhaust for a Invidia Q300. I had my exhaust laying around in the parts department. I saw one of the techs had an R 18 up in the air. A sedan since my car is a sedan. I held up my factory exhaust right underneath the R18 unit. Everything visually matches. Now I wasn't going to physically bolt it on due to it being a brand new car going through its PDI (pre delivery inspection). Also the picture's angles aren't to show true fitment. Pictures are just for reference.

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Ok so that shows if what you're trying to accomplish is add the Si's axle back to the R18's mid pipe. I realize now that I didn't clarify that my intention was to swap over the complete Si cat back system. I figured that if you have acces to a used si muffler that you would also have acces to the Si mid pipe section. But thank you webby for showing me how the axle back could work.
 
Update. So my nephew tried to install the exhaust and came across a similar problem to what Webby was describing. Whether you are trying to install the whole catback or just the axle back, you will have to cut the pipe just after the flange on both systems and weld the two pieces together. It's not as much of a big deal as I've heard it described before. I think it's a really inexpensive way to get 2.5" exhaust system on your car. Just my opinion though. I guess it all depends on how much you can pick one up.
 
How was the connection from the down pipe to the mid pipe section? Did that line up easily? Just curious if the parts bolt together up at the engine end of things.
 
It ends up on the same place but because of the diameter difference you would use the old triangle flange and have it enlarged and welded onto the new piping. Same concept as if you were to only use the axle back like what Webby had posted above. So either you have it done right after the cat or right after the axle back flange.
 
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Thanks for trying this out. Great info for people possibly looking to sell their stock SI system when they upgrade.
 
Anytime. It was easy because my wife's nephew has a '13 EX and wanted better performance without the noise since he's about to have a baby. It only made sense to try it out since it would be less clutter in out storage anyway. I am always glad to help.
 
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