oem muffler dissection

[larryn2o]

i cut up a factory muffler this week , to see how it is made. it had 2 small "glasspak sections and a 180 bend in the pipe . not bad for flow. the bad part is a center divider with a small square door. it is spring loaded and was stuck almost shut. had to be beat open, this is after only 40,000 miles .

one could take a hole saw or large drill bit , make 1 hole in the rear of the muffler and perforate the divider to gain more flow. then patch the out side for a stock appearance.

[cali yaris]

cool. glad someone did that so we could all see!

[yaris2010RS]

lol? u did that at work? i recongnize the rollers on the work bench, lol

i have been planning to open mine up and basically gut it out to get a little deeper sound, does it look possible/practical?

[auxmike]

What's the deal with the hatch then?
Will the car still run if the hatch jams shut?:iono:

[RedRide]

Interesting.
I was wondering what was inside one of those.
Thanks for posting it.

[larryn2o]

there is a small gap in the in-feed tube so that it can flow with the door closed. you could take a hole saw and drill from the top. if placed right it would sever the outlet tube, and eliminate the trap door. that would make it a single chamber muffler.

[larryn2o]

lol? u did that at work? i recongnize the rollers on the work bench, lol

i have been planning to open mine up and basically gut it out to get a little deeper sound, does it look possible/practical?

if you cut it open ,stay to the back side (rear)of the seam , the center partition is welded to the pipes and outer case. you could cut a 3 inch hole in the partition and weld in a racing header insert. this would make the equivalent of a turbo muffler.

http://www.summitracing.com/parts/SCH-42530/

[Bluevitz-rs]

That trap door is supposed to be a performance thing. It's shut to keep the car quiet and maintain back pressure, but when you floor it the pressure is supposed to open it up allowing better flow at the expense of more sound. It's a pretty good setup when it works for a stock muffler.

[yaris2010RS]

That trap door is supposed to be a performance thing. It's shut to keep the car quiet and maintain back pressure, but when you floor it the pressure is supposed to open it up allowing better flow at the expense of more sound. It's a pretty good setup when it works for a stock muffler.

when it works? lol how do we know if it works or if its failing?

[Bluevitz-rs]

I'm just going off of the OP saying his was jammed shut. I'm sure it'll work forever on a regularly used muffler.

[RedRide]

Another reason to go for WOT often. :biggrin:

[yaris2010RS]

im sure mine isnt stuck, i life at WOT and still get amazing fuel economy considering

[RedRide]

im sure mine isnt stuck, i life at WOT and still get amazing fuel economy considering

Exactly.
Even at its worse, the Yaris still gets great milage.
You might as well enjoy what you're driving.

[detroiter]

My yaris seems to like to suck down the gas if I jam on the gas pedal too much at WOT :(

[yaris2010RS]

what do u mean by "suck down the gas"? i drive my car exactly like how any insurance company thinks a 19y/o male would :) and i still get around 500 - 550km (340mi)per tank winter and 600 - 650km (400mi)per tank summer, i cant complain

[malibuguy]

nice to know whats inside

its kinda like a DynoMax VT muffler

[detroiter]

Sucks down like if you were driving a triton v8 Ford engined vehicle and romping on it. Maybe it doesn't suck gas down that bad but I still get pretty dismal mileage and can't figure it out :(

[06silveryaris]

if you cut the loop and connect it directly to exit glass pack it will sound nice. This is one I made for a buddy of mine

http://www.youtube.com/watch?v=gIec-3LFs_A

[cali yaris]

ooh nice GROWL! :thumbsup:

[yaris2010RS]

the rest of the exhaust was stock?

[06silveryaris]

the rest of the exhaust was stock?

yes completely stock, to cut it without damaging the muffler you have to do it thru the center divide on the "pumpkin" . Look at the pics and you will see what I mean. BTW no drone sound in the car

[06silveryaris]

BTW this is the exhaust before modification

http://www.youtube.com/watch?v=z237jRrXVsk&feature=mfu_in_order&list=UL

[Viperoni]

nice to know whats inside

its kinda like a DynoMax VT muffler

Exactly, but the Dynomax is a lot more straight through.
That small trap door hurts flow a lot, and the glasspack part doesn't help flow enough either. Does do a great job quietening though.

[OTA'sTOY]

i cut up a factory muffler this week , to see how it is made. it had 2 small "glasspak sections and a 180 bend in the pipe . not bad for flow. the bad part is a center divider with a small square door. it is spring loaded and was stuck almost shut. had to be beat open, this is after only 40,000 miles .

one could take a hole saw or large drill bit , make 1 hole in the rear of the muffler and perforate the divider to gain more flow. then patch the out side for a stock appearance.

quick question you said it was stuck correct. so the first pic is after you beat it open and the second pic is the before?
if so ever thought that maybe the flap would open toward the rear of muffler instead of towards to front? jus wondering

[marcus]

i didnt know our yaris has that door..i have to check my stock exhaust.

[Viperoni]

On this note, has anybody ever dissected the midpipe's resonator?

[malibuguy]

^ the resonator is straight thru

i was thinking about that valve being stuck...maybe it opens easier when its heated up with the exhaust

[larryn2o]

quick question you said it was stuck correct. so the first pic is after you beat it open and the second pic is the before?
if so ever thought that maybe the flap would open toward the rear of muffler instead of towards to front? jus wondering

it will only open one way , it isn't the only path for flow , after cutting more ,i can see a short gap in the pipe right before the glass-pac section.

[Viperoni]

it will only open one way , it isn't the only path for flow , after cutting more ,i can see a short gap in the pipe right before the glass-pac section.

I've seen that before in the mufflers on my old Buick Roadmaster.

Thanks for the reply on the resonator

[SilToYaris]

Nice difference ;)

[larryn2o]

i just put a 2 inch pipe on a stock flange and ran over the axle to a 2 inch Cherry Bomb turbo. it has an offset so the tip is in the stock location and it all looks stock ."in case the law has a problem with that stuff". it is just a bit louder than stock with no load, some what louder under load. nice sound , no popping or racking off. a noticeable increase in power . muffler $24 at Auto Zone , pipe bent ,muffler mounted and tip at local muff shop. $44. (total $66)
it ain't stainless , but I'll change it in a year or so anyway! :)

[larryn2o]

http://www.youtube.com/watch?v=fPtaWvaIkU0&list=UL

[larryn2o]

http://www.youtube.com/watch?v=px6YOMMcoJg&list=UUrdtSeVKV-ChmSXKgIZJKvw&index=1

new setup twin tip on a 2 inch axle back. it's a pace setter knock-off , $35 at the local speed shop. not as good sound but 1/2 price.
I'm going to tune it a bit to see how it sounds.

[MUSKOKA800]

Don't recall seeing any lubrication/service interval for that pesky muffler flap???
Must have missed that.

[TOUGEghost]

Muffler bearings: perhaps they do actually exist. :laugh:

[yaris2010RS]

Poor Muffler bearing care caused my front tire to go flat

[CoryM]

Muffler bearings: perhaps they do actually exist. :laugh:

:laugh: Well in all seriousness, there are bearings in mufflers if they have doors like that. So yeah, they do exist.

That being said, I had no idea the Yaris had variable flow mufflers. I feel so much more exotic driving my car now. Actually I have always felt my car is a low on power compared to other Yarii. I think I will check that valve, or get a new muffler.

Thanks for taking the time to dissect.

[larryn2o]

A well placed hole saw could be used to modify the stock muffler . I have one more stocker , may be a winter project ? Stay tuned ! Muffler laparoscopy !

[Jason@SportsCar]

Here is the TRD off-road muffler bearing:

http://sphotos-a.xx.fbcdn.net/hphotos-snc6/258772_474463445920315_994484627_o.jpg
http://sphotos-b.xx.fbcdn.net/hphotos-snc6/242083_465569816809678_271975437_o.jpg

[CoryM]

Here is the TRD off-road muffler bearing

ooooooooh! Fancy! Must add a few HP for sure. :biggrin:

On a more related note; How strong is a spring on the door flap? If you take a non-seized one and shake it, can you hear it clack open and closed? Just wondering if there is any viable way to check the function of the door. My car sat for about a year, I don't drive it very far most of the time and my car feels a little under-powered (even for a 1.5L). I think it is entirely possible that my door is stuck. Otherwise I guess I should just cut an inspection hole in it.

[larryn2o]

It's not that strong , and even if it is sticking there is another path for the exhaust to go.
I'm still looking at a way to bypass the most of the internals with little or no welding, hope to get around to it soon.
Nothing against the vendors , I just like to hot rod a bit old school

[malibuguy]

the door may swing easier when warmed up as well

[larryn2o]

anyone have a stock muffler they would donate to ongoing research? i'll pay shipping . i want to do a high flow (loud) modification with little or no welding, using only hand tools and looks stock.
thanks
larry