So I have a borla catback exhaust. I deleted the resonator and replaced it with a pipe just to give it a little deeper tone. I had it done at a muffler shop.

About 3 months later, my exhaust starting getting louder arpund 3-4k rpms. Sometimes, for a short period of time, my car would start to lose power and would only rev as high as 5k rpms.

At first, i assumed it was an exhaust leak. Then the other day I floored it, redlined it and dropped it into second gear and get a very loud POP coming from the exhaust. Instantly the tone of my exhaust got way deeper. Then I went from 0-30mph at a normal acceleration and you coulda swore i was going full throttle. My exhaust is so ******* loud now its not even funny.

It sounds like one pf those riced put vtec hondas. Its a very loud, deep tone to it. In a sense it sounds kinda cool, but its just too loud.

Anyways, I reved my car and looked underneath it and could tell the sound was coming from this black metal box tht is on the driver side of the car toward the back. Kinda lined up with the back of the seats. What is that thing? Should I be worried about it?

Im asking because muffler shops are closed today, and i work all day tomorrow so I need to know if Ill be okay to drive it for today and tomorrow. And if it'll be okynto drive it about 10 miles to the muffler shop.

 

The black metal box could be your fuel tank. So it's not that. You do have a gasketed exhaust coupling in that area though. If the gasket broke or the joint is loose, you would definitely hear noise and rattle.

However, that shouldn't lead to loss of power. Your car shouldn't be backfiring (likely the pop you heard). How old are the ignition coils, wires and spark plugs? Are they all well connected?

 

Yeah, at idle i hear a really loud rattle.

I know that my heat guard on my cat is loose atm too.

Coils and spark plugs were replaced about 5k miles ago.

 

Possibly the cat broke up and clogged the exhaust.

 

You deleted the resonator after the cat?

My guess is you had a clogged cat and blew all or part of it out. I would drop it and see what is going on with it.

Not sure about the power loss, though, unless remnants of the cat clogged the catback or something.

 

Yeah, If the back half of the cat broke up, a piece could get lodged in the pipe or muffler, and the back pressure could be forcing exhaust out at the spring loaded flange donut gasket.