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4 Cyl. dual muffler conversion

2008 Views 9 Replies 7 Participants Last post by  Honda530
O.K., I know this topic has been covered before and I hear a lot about loss of HP. What I wasn't clear on was "Can I maintain the HP I currently have after converting to dual if I use the right size pipes?" The engine and exhaust are completely stock and I plan on keeping it that way except that I would like to convert to the dual muffler look purely for cosmetic reasons. I much prefer the way the V6 looks with the dual mufflers. I would use generic mufflers and tips to keep down cost (I don't care about having a GReddy, N1, or Hayame). All I'd like to know is if I can avoid losing HP by running smaller diameter piping.
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I used to want to do a dual exhaust conversion too, when I had my integra, but that car was all about performance and so taking a hit on hp or torque wasn't gonna happen. basically you're on the right track. if you have both pipes at 2.25" (for na performace) then that's way too much room for the air, however if the pipes are smaller then they are supposed to be say 1.75" (making a number up so obviously this means nothing) then you could get the effect of having 1 2.25" pipe. You gotta do your math to figure out what the magic number will be. but yes you can do the dual exhaust look and not lose hp. Another alternative I thought about way back when was to just hang a dummy pipe, I never thought about it all the way through, so there may be problems involved with that. (ie maybe the sound would be really wierd only coming out only one pipe, and one will get dirty because of fumes, but the other won't, I don't know just quickly thought up ones) Good luck
Thanks for the input 2G. I think I'd draw the line at hanging an extra muffler that wasn't hooked up. I'm guessing that two smaller diameter pipes would be the best method. If that's the case, would I need 2 pipes of approx. 1.6" diameter to equal the airflow area of a single 2.25" pipe?
2.25" pipe = 3.974 sq. in. of airflow
1.6" pipe = 2.010 sq. in. of airflow (so, 2 pipes would equal 4.020 sq. in. of airflow
I have no idea whether this calculation is what I should be using. And doesn't a 1.6" pipe seem really small? All you racers out there - help a brutha out with this conversion.
it doesn't seem any lost for mine... you can't really tell on a V4, plus our accords are inline 4 so you should really worrying about loosing the back pressure. I can't really tell any difference when i had the Dual setup. seems the same, but i think i can start noticing the lost in back pressure a little once i drove my friend's accord...but not much.
JTEVO2Accord is right. losing back pressure is what we should always worry about.

perhaps, our so-called dual exhaust setup is nothing but fake with y-pipe rear sending out 2 exhaust pipe to make it look "dual and cool".
but yes, it does send out more air than single exhaust. We had debate over this in V6 forum about how single exhaust system gives you more stable low-end than dual, meaning slightly better acceleration but dual helps out in top-end. (all this crap is V6 knownledge, doesn't apply for inline 4 though).

What i really like about dual in my accord is that sound is deeper tone that single exhausts. ;)
wouldnt getting a smaller diameter pipe suffice for the dual mufflers?

lol that sounds smart...:p
I put the dual Tanabe Hiper M on mine 4 cyl accord ( Sold my Accord for RSX ), can't feel any lose hps, anyway, accord is not that fast.... no need to worry about too much.
That's just the point. The 4AT is so slow already that I'd hate to lose any more HP just to make a cosmetic improvement.
werd. either way, accord can't be that fast.
unless you have manual 4cyl, and planning to add a turbo.
but it is still not fast enough for F/I car. :(
Well the thing thats hard for me to understand is that with a v6 it goes like 6-2-1 or something well it feeds into 1 pipe. Then goes back and into 2 pipes. Its just hard for me to see this being better for a car. If after the header it just went into 1 pipe wouldnt the v6 be faster??? I have to agree that dual exhaust looks a lot better Hey maybe you could make your own headers. Make them 2-1 hehe so you ahve 2 headers 1 for 2 ports. so that way you dont have to worry about loss of back pressure.
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