Do X pipes have to break in?

spederman

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Apr 13, 2005
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Here's the thing. I got my magnaflow catted x pipe installed at the end of january. Well last week, all of sudden, my exhaust has got a LOT louder, to where its noticable enough where my girl actually asked, why is your car so much louder. I figured i had an exhaust leak somewhere. So today i took it to the shop that did the install. They put it on the lift, tightened everything and didnt see anything wrong. they even started it on the lift and checked for leaks and nothing. They assumed that the cats on the x pipe must have broke in and the car just got louder. I mean, its a good loud, i love it, but its bizaare that out of the blue, one day, it just got louder and it rumbles more to where i can actually feel the vibration of the rumling when i'm driving. It still has all the power it's always had, so i dont notice any negative effects. Anybody have any ideas?
 
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just drown out your gf's complaining with the exhaust! haha I shouldn't say such mean things lol

but no seriously.. I think cats get louder after they are "broken in"
 
Its just wierd though, that it would take 2 months to break in. Like most have said, maybe a couple weeks but 2 months sounds a little far fetched. And the other reason i thought i could possible have a leak is because at light acceleration, like 1/4 throttle, i hear a high pitched hissing inside the car. I drove next to a wall with my windows down and i can hear that hissing pretty loud reflecting off the wall outside. The stang shop said that x pipes can make a hissing sound like that, but i dont know.

How would i know if i have a exhaust leak at the engine/exhaust manifold? I was thinking maybe that gasket is shot and thats why i get a hissing and the engine is more rumbly when i go WOT.
 
My car with the MAC o/r pipe makes that hissing noise also! I did the same "window down by a wall" test also and thought for sure I had an exhaust leak somewhere. I have jacked the front of the car up on jackstands and put a rag in each tailpipe (to create pressure) and crawled under checking for leaks. I cannot find any at all. The noise is only at partial throttle under a load and is anywhere from a hissing sound to a tinny rattle sound.

I am just going to assume it is the nature of the pipe and go on. If you find anything else out, please let me know.
 
spederman said:
How would i know if i have a exhaust leak at the engine/exhaust manifold? I was thinking maybe that gasket is shot and thats why i get a hissing and the engine is more rumbly when i go WOT.
To check at engine/exhaust manifold for leak: Open the hood, start the car, and move the throttle with your hand while listening closely. If the hissing noise becomes less noticeable at higher rpms, then you have a leak there. If not, you have other problems.

Lots of people find their exhaust leaks when they replace a midpipe at the header/midpipe connection. This can also be a pita. Do a search on this and you'll find 18million threads.
 
soctty7676 said:
My car with the MAC o/r pipe makes that hissing noise also! I did the same "window down by a wall" test also and thought for sure I had an exhaust leak somewhere. I have jacked the front of the car up on jackstands and put a rag in each tailpipe (to create pressure) and crawled under checking for leaks. I cannot find any at all. The noise is only at partial throttle under a load and is anywhere from a hissing sound to a tinny rattle sound.

I am just going to assume it is the nature of the pipe and go on. If you find anything else out, please let me know.


Wierd, that's exactly how mine sounds, hissing to sometimes a tinny rattle. Maybe it is just an X pipe sound. I guess i wont worry about it unless something breaks. :shrug:

BTW, WTF happened to this thread, why is it so wide all of a sudden?
 
spederman said:
Wierd, that's exactly how mine sounds, hissing to sometimes a tinny rattle. Maybe it is just an X pipe sound. I guess i wont worry about it unless something breaks. :shrug:

BTW, WTF happened to this thread, why is it so wide all of a sudden?
Meh, an exhaust leak won't break anything, so no need to worry. Just when you have some extra time, climb under and check for leaks and re-tighten everything
 
Ok, I checked again for an exhaust leak, I opened the hood, ran the car, revved it, didn't hear anything. I then did the "stuff the rag in the tailpipe" trick and still didn't find any leaks.

So this weekend after spending too much money and time (MIL Elim's) trying to get rid of my SES light, I took off the MAC O/R pipe and put the stock back on.

Guess what! I still have the same noises, but they are just A LOT quieter. So, I think these noises are normal, but the larger 2.5 pipe with no cats just makes these hissing, rattling sounds louder.

In any case, I can't get it to fit correctly so I am selling it. It is for 96-98 GT's, but I am wondering if 98 was a little bit different or something.

It is also too freakin loud. I liked the sound of it at first, but it seemed to get louder and louder, then Saturday a cop followed me into a parking lot and gave me the speech about loud exhausts and how he is doing me a favor by not looking under the car and looking for catalytic converters.

Oh well, I am going to be doing the PI headswap soon, hopefully that will work out for me!