well, looks like my muffler decided to suddenly open up several holes at once that had been rust spots, I guess scraping it on a dirt embankment probably didn't help much. Now my 4runner sounds more like a giant lawnmower, but I'm curious, is it actually bad for the engine? It seems to me that it accomplishes the purpose of a larger diameter exhaust system in that it relieve back pressure, and I'm not too worried about toxic fumes because well, I don't exactly stay in place for very long when I've got the engine running. I did plan to look into upgrading my exhaust, but it wasn't really all that high on my priority list. Is there some reason I should move it up? For now I've played around with a few home patches: aluminium tape, steel epoxy, aluminum can and high-temp gasket silicone, and so far they've all either burnt off and/or blown out so I've just settled with driving around with an annoyingly loud exhaust.

 

Well as long as the local law does not pull you over and start writing tickets.

Then it really won`t hurt anything in the engine.

The fumes could be a issue on long trips or if you get stuck in traffic crawling along.

Me the noise would give me a headache.

 

Gaping holes in your exhaust doesn't mean you opened up more flow, your still going through the cat and the pipe.

 

You're right, it is relieving back pressure, any although there negligible increases in power or economy. It won't hurt anything. You have 1 o2 sensor before the muffler, so as long as it's intact and functioning, you could cut it all off with no ill effects. If it annoys you too bad, sure patch it up with whatever you want. A turbo muffler and installation should only be $60-$80 installed.

 

here's my muffler after a nasty backfire when we were starting it up after a total overhaul...



I went with a thrush turbo muffler from O'Reilly's, only $30 and I have $10/hour access to the welding shop on base. It shouldn't be anymore that $50 like vasinvictor mentioned to get it done at a monroe or something.