Is the resonator/muffler position on a Mirage "abnormal"?

[wellswebdesign]

On all the cars my wife and I have owned (91 Accord, 99 Saturn, and 10 Accent), it has always been resonator -> muffler -> tip. So I got down on the ground and looked underneath my Mirage and saw something that surprised me. I was surprised to see the Mirage goes: muffler -> resonator -> tip. Is that common on other cars and I just don't know about it?

[flotownj]

I see cars like that across the pond all the time in the middle east. Don't know why thou...
On a side note that muffler looks huge for a 74hp 3 cyl!!

[Tinker1980]

It's more common on rear-wheel drive and four wheel drive vehicles. I think the reason it's different on the mirage is the short distance between the rear wheels and the back of the car.

[wellswebdesign]

Interesting, good to know, thanks.

With our Ohio winters and my short commute, I was replacing the exhaust and muffler on my Saturn every 4 years. I'm hoping this muffler position might help it get up to a higher temperature quicker and not rust out so fast.

[Tinker1980]

Interesting, good to know, thanks.

With our Ohio winters and my short commute, I was replacing the exhaust and muffler on my Saturn every 4 years. I'm hoping this muffler position might help it get up to a higher temperature quicker and not rust out so fast.

If anything that will be counterproductive... the heat combined with the water and excess of salt will cause the chemical reaction to go faster, meaning more rust.

[wellswebdesign]

If anything that will be counterproductive... the heat combined with the water and excess of salt will cause the chemical reaction to go faster, meaning more rust.

Huh. I've always been told that short drives don't allow the exhaust system to heat up completely and "cook off" all the condensation that collects in the exhaust, thereby rusting the exhaust from the inside out. I know many people with longer commutes whose exhausts never need replacing. Either way, I've got a brand new exhaust, at least for now.

[IchabodCrane]

^^ X2 ^^
Your exhaust will last longer if your trips are longer!
Short trips do not heat components sufficiently to remove moisture/condensation and will lead to corrosion and/or water issues.
Salt + steel + heat + moisture = far more corrosion than
Salt + steel + heat - moisture.

[GrnBn]

The muffler is a two-pass design, which explains the larger than average size for our motor. Something I haven't seen mentioned is how replacing the OEM muffler effectively shortens the total distance the exhaust travels, which changes its resonance. I think this is a factor in why turbo-style mufflers lose power on this car.

[namco]

The muffler is a two-pass design, which explains the larger than average size for our motor. Something I haven't seen mentioned is how replacing the OEM muffler effectively shortens the total distance the exhaust travels, which changes its resonance. I think this is a factor in why turbo-style mufflers lose power on this car.

its not a 2 pass design. the muffler is a straight through, with 3 chambers. the main pipe goes all the way through, but there are holes in the pipe which allow air to trickle out into the chambers.

at low rpm, the exhaust flow is slow, and thus the exhaust gasses end up going through the little circle cuts in the pipe, into the triple chamber. this also helps with scavenging the gasses.

then at higher rpm, the gasses have a harder time exiting those wholes into the triple chamber, and pretty much bypass it by a %. this is the same for any similar style exhaust including glass packs. in a glass pack muffler, you have a inner pipe and an outer shell. between the inner pipe and outer shell is glass packing material. there are some kind of holes in the inner pipe to allow gasses to go into the glass pack material. at low rpm the flow is slower and thus you get more air in the holes and into the glass packing making for a quiet exhaust, at high rpm it skips the holes and acts like a straight through pipe by a better % than stock.

the reason why "an aftermarket exhaust" seems to "not make power" is that (from what I've seen) everyone is placing the muffler at the back where it would traditionally go (because of X reason) and thus changing the way the exhaust works. if the muffler was kept in the middle of the car like stock, and then just straight pipe to rear (or to a resonator) you would retain similar stock exhaust but with a slightly larger pipe diameter thus making power instead of losing it. the muffler was probably moved further back (or forward, depending on your view) towards the header to promote better scavenging and thus better torque and flow for this motor. when people make aftermarket exhausts, they usually keep the stock design, just larger pipe and higher flowing mufflers so when WOT you get the best flow thus the best performance. this car CAN gain from an exhaust, it just takes someone smart enough to do it.

[cyclopathic]

^^^ I'll bet stock exhaust exhaust takes advantage of Helmholtz effect and is tuned for specific frequencies. Increasing cross-section would also require increase in chamber volume to maintain designed tune.