Sorry for my ingorance about performance, but I have a few questions regarding headers I just purchased. How much HP will my 98 Civic EX gain. How significant will the sound difference be, if any? I just bought a JDM Style exhuast headers, any reviews on this item?
Thanks!

 

its going to be much unless u already have intake and exhuast. even then its not really going to be THAT much. i would say about 10-15 hp with I/H/E

 

I have an AEM sri, if that helps.

 

it does help , an intake is an intake however u look at it. but if u really wanna gain HP u should save up and piece a turbo kit. or do a swap which is more expensive but if u got the cash go for it. ii was gonna go the turbo way but decided to do a swap im really happy with my desicion

 

HOLD up headers dont give u 10-15 hp i would say about 5-7hp or 5-10max and a nice little set up would be header, intake and full catbackexhuast... u can get about 15-20hp with tht setup.

 

I think he ment that I/H/E together will gain that much.

 

headers CAN give 15-20... but not on a civic lol.

 

How much gain would a header give on a new Civic Si sedan? What is the best brand/model to get? Also what about a catback thats not much louder then stock to match the header? Which one? Brand/model. If I was to put on a header, catback, and a low restriction cat, how much would I gain? I am thinking about doing it, I just don't want warranty issues. In about 18 months Imightbuy a 2009 BMW 135i, 300hp 300tq @1400rpm. But until then I want to make my fun Si sedan more fun.

 

I don't think you can change your header or cat without voiding your warrenty. You can add a catback and an intake though.

 

in the honda warranty manual, it says you can't mess with anything that alters emissions, which includes the cat