Wait, what's the muffler for?

[H3LlIoN]

So...I'm a muscle car transplant, in case I never said it before...new to tuning asian cars. Why do we need a muffler? I tend to not use them on american muscle... Is it just tone? I know backpressure is an issue on imports, but I don't understand anything about it. kthx

[cali yaris]

cuts noise. that's it. if you like it loud, chop it off and make a pipe -- at least a couple members on here have done that, I think.

[kustom play]

mufflers are put on by "the man" to keep you down

[H3LlIoN]

Alright word, that's what I was thinking...just wanted to make sure. I'll try a straight pipe first with audio clip for comparison and go from there. Thanks

[skoolafish]

Originally Posted by kustom play

mufflers are put on by "the man" to keep you down

*snaps fingers* i knew it...

[127.0.0.1]

mufflers keep your neighbors from snapping in the
middle of the night and blowing your whole house up

[markitect]

The back pressure helps with fuel economy mostly, and low rpm torque a little, and is mostly important to the EPA.

Basically the valves let some exhaust back in(pushed by the back pressure) during the intake part of the cycle at low rpms. This is equivalent to the EGR on non variable valve cars, which your more likely to be familiar with(if your not, basically EGR lets some exhaust back into the intake at low engine load).

Keep in mind that the engine will still suck in exhaust, just not as much.

[kou]

if you chop it off and replace with just a pipe it will be way too loud with NO power under 3500rpm.order one dynamax muffler #17702 an get an exhaust shop to weld it on,you will be happy with the sound.

[yarr_is]

cause most likely import scene is targeted more than the muscle scene... so we have to play it by the rules.

[H3LlIoN]

Originally Posted by kou

if you chop it off and replace with just a pipe it will be way too loud with NO power under 3500rpm.

Do you have supporting evidence of this? The other guy said it's basically just EGR, which on normal engines is just a type of gov't imposed restrictor, and one of the first things we ditch.

[thebarber]

Originally Posted by kou

if you chop it off and replace with just a pipe it will be way too loud with NO power under 3500rpm.order one dynamax muffler #17702 an get an exhaust shop to weld it on,you will be happy with the sound.

so you're saying that removing the muffler and adding a 1.75" pipe would create a greater loss in back pressure vs adding a muffler thats 2" thru?

im not sure you know what you're talking about

i added a megan muffler thats at LEAST 2.25" thru and barely felt and change from stock except it was louder and i had more top-end power

it wasnt until i removed the section of midpiper between the back of the resonator and the axle that i felt a BIG difference. didnt really lose and bottom end, but it significantly increased midrange and top-end power.

106whp and 107wtq with intake, custom midpipe and megan axleback....

[kou]

I have tried this with a 2inch striaght pipe from the axle back,and only found a big niose gain and a large tourqe loss at low rpm's.I am sure power would be made close to redline but who wants that on a daily driver.I first had the TRD muffler found a loss of tourqe at low rpm but it was great up top. Got rear ended muffler got ruined but i was able to save the pipe that goes over the axle,tried the striaght pipe then.For a good all round mufffler thats not to loud, free flowing but still keeps some backpressure the dynamax 17702 is great.

[kou]

Originally Posted by thebarber

so you're saying that removing the muffler and adding a 1.75" pipe would create a greater loss in back pressure vs adding a muffler thats 2" thru?

im not sure you know what you're talking about

i added a megan muffler thats at LEAST 2.25" thru and barely felt and change from stock except it was louder and i had more top-end power

it wasnt until i removed the section of midpiper between the back of the resonator and the axle that i felt a BIG difference. didnt really lose and bottom end, but it significantly increased midrange and top-end power.

106whp and 107wtq with intake, custom midpipe and megan axleback....

The dynamax muffler is not a straight thru design.

[cali yaris]

only found a big niose gain and a large tourqe loss at low rpm's.

"large loss". No dyno, right?

[thebarber]

i seriously find it hard to beleive that you noticed a "huge" loss in low end tq in a car thats only got 92tq at the wheels to start

like i said, i added an axleback and didnt notice any change in power except north of 5500rpm....not where i drive daily, but from dyno graphs you can see the power chokes in the upper rpms due to lack of airflow

only time i noticed a significant change in power was by removing the stock 1.75" midpipe for something bigger.

in my opinion, the muffler is restrictive, but removing it completely versus just changing the muffler doesnt do anything but change the sound of the car

edit: kou, your garage shows you have a 2" res-back exhaust.....at what point did you change the midpipe? when you went with the mufflerless setup, with your stock axleback or with your dynomax?

[darthbauer]

idk about losing power and all of that but it is going to be louder than hell. I once heard an RSX type S with no cat and a straight pipe and it was crazy loud.

[thebarber]

Originally Posted by darthbauer

idk about losing power and all of that but it is going to be louder than hell. I once heard an RSX type S with no cat and a straight pipe and it was crazy loud.

you'd be surprised how much things like the cat and resonator also muffle the noise coming out the tail pipe.

i had a friend w/ an xrs remove his resonator and replace it with a muffler and it totally changed the sound of the exhaust.....imo, was too loud....

[kou]

All i can say is try it out i did and this is what i found. i could accel faster in 1st and 2nd gear with a stock muffler or dynamax muffler than with a striaght piece of pipe. Barber i changed to 2inch resonator back with stock muffler first, better pick up down low but not much after 5800rpm then went to the TRD muffler felt a little loss down low but powered to redline then tried 2inch striaght pipe axle back and it was loud and slow down low and quiet and fast up top,then i went to the dynamax muffler which was an even trade between the stock muffler and TRD muffler.