help with exhaust specs

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B

BlackLs/Vtec

New Member
Hi i would like to introduce myself as i am a new member of the forums. I may be a noob to the forums but thats because anything ive ever needed was already answered here and i do search. i have one question that i cannot find any answers to. i am running a 99 civic ex and my goals with the car are fairly simple. i want a fast n/a civic but i hate the attention that just an exhaust setup will draw. I have a pretty basic ls/vtec setup b18a1 with a b16a head on it and itr pistons the car is quick but im not trying to go supercar or anything crazy its still a daily driver and looks bone stock(and exceptionally clean if i do say so myself). ive heard of people knocking the baffling out of their stock muffler/resonator or whatever and running a high flow cat and headers and it will still look stock but give a little performance. i know that a full setup would be ideal but its just not gonna work out for my situation. my question is if i run some nice headers with a 2.5 out on it to a high flow cat is the high flow cat going to mount right up to the stock exhaust out the back, or is this setup going to be more of a pain in the ass than i think. i would imagine the tube is way smaller and wouldnt mount up right. this is my first civic and i have nobody to guide me the right way and you guys have done it for the past year so please if you could help with my discreet setup let me know if not please dont flame.---oh but i totally am a forum noob and accidently clicked the wrong hybrid forum...could a mod. please move this...sorry:(
 
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running a 2.5" collector and 2.5" inlet on the cat wont make much power if the outlet is the stock civic pipe size anyway.... you just move the restriction further downstream, but it's still restricted. knocking out the baffling of your muffler and cat will essentially make your exhaust a straight through design, making a TON of noise, but little power since the stock design doesn't restrict flow much. the restriction is in the pipe size, not so much the baffling. you would probably pick up 2-3 hp if you hollowed it out, but i'd be willing to bet that it's louder than a 2.5" exhaust/collector/cat combo, and makes less power to boot.
 
So basically id just be making my car sound like shit for power thats not worth it. Makes sense. Well im still trying to figure a sneaky way to keep the car looking bone stock from the outside and get all the little power i can. If anyone has any suggestions or done something similar sleeper style let me know.
 
run an aftermarkey header,2.5 inch exhaust and then put stock axle back on there..it will look stock but have a little throatier sound
 
You want a stock looking exhaust? There are several made that look stock and are quiet. You could always buy a stock looking performance muffler and get it custom made up at a shop.
 
you could always buy an electronic exhaust cut-out. have it welded in before the cat then when you flip your switch in car, it essentially makes your header a dump pipe. when it's closed, you have a full exhaust and converter, when open, you have a deafening exhaust note with some more power, but still unless you have other mods, an exhaust isn't going to make much power. I'd personally save the money towards a swap. then you can have a very quick honda, and keep the stock exhaust for stealth and sound suppression. the highest flowing, ear blood inducing, exhaust you can find is only going to make 3-5 hp on a stock civic.
 
he has an LSvtec.

And just run your header, 2.5" piping all the way back to a stock SI muffler.
 
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