I am planning on getting an ls or GSR engine for my 99 Civic coupe and I was wondering if I have to get a new exhaust system or can I use the one I have on my car now?

 

You can use the one you have now. Just have a custom length cat made to fit the difference.

 

Good, I thought I was going to have to get a whole new exhasut system.

 

what kinda exhaust do you have? and do u have any plans on moding the motor?

 

You may want to think about a wider exhaust to allow the larger engine to breathe better. Not necessary but definitely recommended.

 

^^yea for sure. your going to be pullin in air alot faster and u need to be able to get it out just as fast. increase your piping size and get a different muffler. the car has to be able to breathe.

 

What would a good piping size be?

 

just look into an aftermarket exhaust for the civic. have the correct diameter catylitic coverter to match. they all should be around 60 mm in diameter which is fine for the swap.

 

i recommend headerback if u really want the power. and go with 2.25 inch piping. i was running a 2.25 inch apexi N1 catback with a 26inch resonator on my coupe when i had my single vtec, cuz i wanted it quiet.. but now that im runnin ls vtec i kept the piping size but had it mandrel bent, i did headerback instead and removed the resonator. i would recommend something thats mandrel bent like mine, and not welded up. if you have the money then thats your best bet. u get the sound, power, and your car will breathe wonderfully.

 

I was thinking about getting the HKS Hi-Power exhaust:

http://www.hopupracing.com/hkshiexcisie.html