2003 Accord Coupe - Dual Exhuast on the I4?

Hello everyone!

I'm new to this forum, so hope I chose the right spot to make this thread.

Ok, here's my situation. I recently purchased a 2003 Accord Coupe with the I4 - I also put the Aero body kit on it. The rear skirt has cutouts for dual exhaust, even though my I4 obviously only has one pipe.

I don't have room under the car to mount a heatshield and pipe from the engine, so a true dual exhaust isn't possible. My idea is to somehow run a pipe from the existing muffler (perhaps before it, with a Y joint?) to a second muffler. This would be completely superficial, but would look super-sweet with some nice tips.

Has anyone done this, or know of someone who has? This is my first car, so I've never had a chance to get into any sort of mods.

Thats a great way to lose hp.

How so? Disrupting the airflow?

I'm not very knowledgable about stuff like this, so could you explain the cons of doing this?

Originally posted by darkaccord
Thats a great way to lose hp.

Well, I think he thinks because it's not giving enough backpressure. But if you are running the stock exhaust manifold and cat you should have plenty of backpressure.
For some reason dual exhaust on a 4 banger is shunned in this forum. I think it's a good idea, for looks only of course. It probably won't give you much gain in HP.

I'm no expert on this, but your messing with something that was designed to work with one muffler. It may be possible however.

Haha... too bad its shunned. I'm not looking to gain HP (although it would obviously be nice) but I don't want to lose any, either. I'm more doing this for aesthetics - I figure I have the cutouts in the rear skirt, so why not make it LOOK like it has dual. Everything on my car is stock (just bought it). I'm just looking for a good way to do it.

Originally posted by PWMAN
Well, I think he thinks because it's not giving enough backpressure. But if you are running the stock exhaust manifold and cat you should have plenty of backpressure.
For some reason dual exhaust on a 4 banger is shunned in this forum. I think it's a good idea, for looks only of course. It probably won't give you much gain in HP.

Now that I reread your post I see what he was talking about. The way you are describing it is that you will have 2 mufflers. Yeah thats dumb. Just take it too a muffler shop and tell them after the cat you want to Y it and run dual exhaust out the back. You need to buy 2 mufflers to do this, but it will be closer to a true dual exhaust. And it will also cost a good bit too, like 300 or so depending on how expensive mufflers you want to get. And do you want your exhaust to be really quiet? Or would you like some more sound? It would be worth it to invest in some high flow ones, which will be louder but will give you more HP.

You just said that having two mufflers is dumb, and then told me to go get two mufflers? Haha... I'm confused.

I figured it would be expensive, but money isn't too much of an issue as long as its not outrageous. I don't want more noise, its mostly the looks that I'm going for.

I'm actually pretty surprised more people haven't done this sort of thing.

Originally posted by PWMAN
Now that I reread your post I see what he was talking about. The way you are describing it is that you will have 2 mufflers. Yeah thats dumb. Just take it too a muffler shop and tell them after the cat you want to Y it and run dual exhaust out the back. You need to buy 2 mufflers to do this, but it will be closer to a true dual exhaust. And it will also cost a good bit too, like 300 or so depending on how expensive mufflers you want to get. And do you want your exhaust to be really quiet? Or would you like some more sound? It would be worth it to invest in some high flow ones, which will be louder but will give you more HP.

Originally posted by Defkkon
You just said that having two mufflers is dumb, and then told me to go get two mufflers? Haha... I'm confused.



No you had one muffler after another in line with each other. In other words you have one pipe with 2 mufflers on it, and that will restrict. I said Y it and get two mufflers, in their own seperate lines.
Actually, what would be better is to get a muffler that has a single inlet and dual outlet. That wouls be a lot cheaper than getting 2 mufflers and a Y pipe.

Ohhhh... I see what you're saying. Sorry, that would be due to my bad wording in my first post. My original vision didn't have two mufflers in series - but that's what my wording made it sound like

My original idea was to Y the pipe at the back of the car, BEFORE the first muffler... and run a pipe to the second muffler. I was just wondering if there were problems with that.

Thanks for the info PWMAN!


Originally posted by PWMAN

No you had one muffler after another in line with each other. In other words you have one pipe with 2 mufflers on it, and that will restrict. I said Y it and get two mufflers, in their own seperate lines.
Actually, what would be better is to get a muffler that has a single inlet and dual outlet. That wouls be a lot cheaper than getting 2 mufflers and a Y pipe.

it wouldnt be expensive at all to weld in a y-pipe, but it will hurt your lowend pull. why not have the left side shaved in... looks nicer and would serve more of a purpose than an unnecessary dual exhaust.