ok, i took my 01 accord sedan ex I4 to a local muffler shop cause I wanted to add dual exhaust to my car. I really didnt know how it could be done, so I asked the guys at the shop and they said they could do it. They cut right behind my stock muffler and ran piping to the other side and welded on another muffler. now ive noticed some gradual changes with my honda. it shakes sometimes after i crank, takes off slow, and i really dont seem to be able to drive very quick. does anyone know if it can be related to my exhaust? HELP PLEASE!!!!!!!!!!

 

i dunno... id say the best thing to do is go back to the muffler shop and ask them what the problem may be.

 

Thats always the most logical action to take for the time being..

However, I have wondered if doing that to my exhaust would effect it. My thoughts are this-- There is the same amount of pressure & back pressure because you did nothing with the diameter of the piping. All you did was add another outlet, so I'd assume that physics would come into play and send equal amounts of gas/exhaust through both outlets/mufflers. Thus, nothing should be effected by this.

Perhaps the genious P_Adams will have some much more wise input on this subject, but I am dying to know what the problem is as well!

BUMP FOR A HOMIE!!

 

Hooray lack of back pressure!

That would be my guess - or something along those lines.

 

yep. back pressure. he created another outlet for the gasses. thus less back pressure. i can see if he just made his exhaust bigger but he created another hole. get your single exhaust back on. your I4 wasnt made to have dual exhaust. if you want dual exhaust, swap in a V6 for your model or find a V6 model.

adding on a dual exhaust wont net you any gains but less performance. i thought about doing that myself, but realized that if i did not only would it look ricer(nothing against you) but it would hurt my motor rather than help it.

 

If by "My Muffler" you mean Number #14 (Resonator) then I can't see any reason why you're suffering a power loss, UNLESS they inadvertantly caused a restriction to the gas flow where they attached the second pipe / muffler assembly. If they did everything correctly, there would be actually be a net gain in exhaust volume control



Are there any other indicators? Warning lamps etc?
A lazy Primary O2 sensor (#31) can often cause the symtoms you're discribing, poor performance / poor milage etc; but it usually sets a DTC code also.
Don't go out and pick up one of those yet, as I'm not to the point of condeming it YET.

See if there's anything else that you can think of (as to hints or observations).

P

 

P, I think my "muffler" he means #1 in the picture. Idk if he used a second resenator

 

my guess is the extra hole for gas as well. if your car isn't a v6, you should have left it alone. sure it may look cool but at what expense. you might be able to pull it off if you were boosted though. if you wanted a dual exhaust, your better of having a dummy muffler in place.

 

dual exhaust on Inline 4 = silly ricer

 

Lack of back pressure could be the culprit, 2x 2.25" exhaust would create way too less of restriction I would think.

 

no, the hole was cut in the bend right behind my muffler. i also had an aftermarket intake put on my car. do you think that could be causing the problem?

 

the f23 is a low compression motor, dual exhaust will rape your back pressure ... plus lose your low end torque ... and im sure the way they ghetto rigged the secondary muffler isnt helping either ... the best thing is to change it back

 

OK all you lack of back pressure experts. Can anyone tell me exactly how much back pressure this setup will cost this guy? Remember the pipe he added is longer and has an extra 90° (I will assume) crush bend. By adding a longer pipe of the same diameter with a crush bend, to a shorter exhaust? Isn't more length and a reduced diameter (Crush Bend) considered a restriction. Yes he may see a very slight drop in back pressure. I don't see it being a major problem. The exhaust is still mainly going to flow strait out the original muffler, unless it is a very restrictive muffler.

Did they reset your ECU after they did the exhaust work & added the aftermarket intake? I would hazard a guess that the ECU is having a hard time adjusting to the new addition of air flow vs lack of back pressure in the exhuast. But that's just my opinion.

 

It may well be a good idea to re-learn (re-cycle) the PCM so that it can calibrate to the new truths.
I believe that as long as the original Fuel Injectors have sufficient excess capacity, the PCM will be able to compensate (mantain the correct a/f mixtures) for the additional? flow.

Unless they inadvertantly caused an exhaust restriction, I would think something else is at work here.

P

 

it's not lack of back pressure.

Pretty much to a man, everyone here will tell you that replacing the stock exhaust with an aftermarket one will add HP because it is less restrictive. It's not like he put a sewer pipe on after the header. He added a restrictive muffler and what I'm assuming is crush bend piping to a stock exhaust. The major restrictions to the system are still there.

 

your intake is not at fault my any means. one is air coming in and one is air coming out. if anything, it would be your computer trying to recalibrate itself and can't. but i suspect its definitely in the exhaust work.

 

well if you want to test if it is a lack of back pressure that is causing your problem, couldn't you plug up 1 muffler?
I think eddie murphy used a bannana, but you could try something more sophisticated.

 

back pressure is not the issue. the problem with going with too large exhaust on na cars is keeping up the velocity up.

think of it this way. you've got a garden hose with 1/2"diameter. the exhaust will come out very fast but its also too restrictive and by going with a larger diameter hose say 1 3/8" you can get more water out more efficiently. if the hose is too large like a 2 " or 3" then the water is just going to fall out making the pressure drop.

its all about finding the right size to get as much exhaust out as fast as possible. back pressure is completely irrelevant in this discussion.

 

No need to throw any sophistication ( = complication) into it, a potato works A1...lol

 

Agreed!

Matter of fact, he probably added back pressure (not to mention weight) depending on the bend they used, the piping diameter, blah, blah, blah...

I know this is counter-intuitive, but it's a matter of fluid dynamics! For instance, adding another muffler might have lowered the exhaust gas temp, which will actually increase back pressure - who knows?!?!?

I do know, from reading Honda threads for 8 years, that going from 4 -> 2 -> 1 -> 2 seldom works out, from a performance perspective. Sure, it'll give you a little extra top end, but the rest of the power range usually suffers as a result.

Having said that, some ppl like the *looks* of dual exhausts, sooo...

I would temporarily remove the axle-back section, e.g. the dual mufflers setup, drive it around and see if it makes a difference.

If your ride quits shaking, and the power returns... you'll know what the culprit is!

 

Ah, yes! The old "Potato up the Tail Pipe trick"!

apologies to Eddie Murphy

P

 

i went back to the muffler shop and had them cut the extra pipe off. im gonna drive it aroud and see what happens. ill let you guys know what happens.