What Happened??

[Dirt Claude]

Here's a strange one for you.....

I swapped out the muffler on my wife's 98 4Runner about 3 months ago because it was rusting out. To keep things simple, I went with an aftermarket OEM setup so I could just directly bolt it in (that's a whole other story). I immediately noticed a loss of power and MPG with the new muffler on. I decided that I would eventually swap it out with something better when I had the time and money.

Fast forward to a week ago...I finally get around to swapping out the muffler and crawl under the truck to take some measurements for the new performance muffler. It appears a gorilla crawled under the truck and smashed the muffler with his hands. Keep in mind this is my wife's daily driver and sees no off-road action. After careful examination, I have determined that there are no visible impact marks on the muffler as if something smashed into it. The muffler seems very strong and rigid. When I stand on it, it doesn’t even flex or cave in. Weird!

The only thing I can think of is that it caved in on it's own. Kind of like the pop can experiment. Boil a can in water, flip it over and then it crushes itself. Could this be the same thing??

I do have to say that it was easier to justify buying the new Magnaflow, it's awesome!

- Brad

[Funrover]

Impressive!

[Roostercruiser]

ive seen that episode on monster Quest of the elusive muffler crushing gorilla. lol

[Chris]

I will speculate there's an obstruction in there some where causing the decreased performance, mpg and ultimate demise. Cut that sucker open!

[Patrolman]

Any chance the truck was rear-ended? That might be the weakest point. I have to vote for the funky pressure bit though. I agree, cut it open!

[Dirt Claude]

As far as I know the truck was never rear-end, unless my wife isn't telling me something!
I agree, I think I'll slice it open and dig in.

[Brody]

It is the start of an alien invasion! After they got tired of 'doing' the cows and a few humans, they are now trying the same 'invasive' techniques on the cars and trucks we drive.

This happens to be the end result.





I have never seen anything like this. It looks as though suction caused it to fold inward, where you would think an obstruction would cause it to blow outward, then split. I would also say to operate on it. We are all curious....

[Pathrat]

I was showing GateMonkey the muffler and examining the pictures. The thing is creased inward at the midpoint, which to me would be one point for a pressure differential. Then GateMonkey took his soda can, created a seal, removed the pressure and of course, the can collapsed inward at the midpoint. We didn't feel like boiling a can tonight. I don't know much about mufflers, but my vote is for something along the lines of a lack of internal pressure that deformed said muffler.


This is of course only to be considered if the Bigfoot is found and he has a credible alibi.

[Tye]

:confused: wtf

[gm4x4lover]

a back fire can cause it as well.

[5280Hawk]

were the hangars out of whack?

If the tail pipe goes straight back, she could have smacked it straight on while backing up.