jpohl402

Hello,
Am attempting to gather opinions on here for added knowledge.
Getting ready to take my car to a muffler/exhaust shop for inspection....

E63 - Have VRP X-Pipe, Meisterschaft Mufflers/Tips

On a recent road trip, I pulled into a rest stop. While pulling out, I saw a small bump/hump (like a speed bump) leading onto the roadway. It didn't appear to be very big, however was unavoidable. I slowly went over at an angle, and the bottom of the car scraped (unsure exactly where). This was five days ago. Since then, the entire exhaust note has changed. It lost it's deep, throaty, low-pitched growl, and sounds worse (a bit higher pitched) then the car did stock. Not as extreme, but in the direction of a Japanese sport bike. Assuming I broke a weld or crunched a pipe, resulting in backflow of pressure or something, though I have no check engine lights. Maybe someone will know exactly what I should look for?

Thanks in advance.

jturkel

holes? leaks? dents?

you wouldnt get a CEL unless it took our your primary cats or somehow disconnected your O2 sensors

shardul

iTrader: (1)

probably a fracture some where in the system

jpohl402

Guys-
I had a very trusted Mercedes-specializing Tuner/Mechanic take a look at my car a few days ago...
He told me the exhaust problem was definitely due to the Sec. Cats, when tapping them w a rubber mallet you could hear pieces bouncing around in there - he thought the honeycomb interior was falling apart. He was also unsure whether or not this was caused by any impact. Anyway I took it to one of the local dealers (because the cats are covered under 80k/8yr warranty.) After performing a test per Mercedes guidelines, they informed me that the Sec. Cats passed the test, and I would be charged the diagnostic fee (as discussed earlier if no problems were found.)

Now at this point I informed him of my thoughts on situation/slight scrape, and he assured me (then said he will have tech go back through again to look) -- that there is no cracks/bends/crunches/broken welds in my exhaust system WHATSOEVER. Now I'm confused what caused such a change in my exhaust note. I could care less whether one, two, four, or zero cats were replaced - I would just like my car to sound the way it used to/and should in my eyes.

Any ideas?
Much thanks

jpohl402

No theories ?
This is driving me nuts.
Maybe I should just sell this car.

kjlindgr

If the element inside your cat is crumbling, it's all together possible a piece broke free and got lodged in the exhaust downstream somewhere...or inside the muffler.

I'll buy the car for $20K cash if you decide to sell. Sorry I can't offer more, but nobody wants a Merc that sounds like a crotch rocket.

jturkel

delete the secondaries. your care will sound louder/nicer and still pass emissions

if that doesnt resolve the problem, change your primary cats.

jpohl402

^^^

When I delete the Secondaries, what piping should I replace them w ?
2 1/2 or 3 in ?

Thanks in advance....

jturkel

not sure what size the piping is in on your car. your exhaust shop will know (or perhaps someone else on this forum). its probably 2.5 or 3. i'd stick with the same size as stock as going larger than stock could result in a lost of back pressure which isnt necessarily good for an naturally aspirated car

jpohl402

That's probably close to what an 07 is worth now, with the way these things depreciate...

jpohl402

So if you read my second post in this subject about my mechanic's diagnosis, you will learn I took my car to the dealer, nothing was found to be wrong, and I was charged a labor fee. Now when I just informed my mechanic of this, he stated the cat will pass a computer test, but they technically should have removed the down pipes to see what was rattling. Obvioulsy I got nowhere - but difficult to discuss with service advisors exactly what I want done because typically I know more about my own car than they do. And I believe they wouldn't go through all that trouble to remove downpipes on a whim, if something is passing the computer tests.

So my question is if there is another way to have the cats tested, and if so / & they are in fact bad, can I go back to that dealership, prove to them the cats were indeed bad, and receive a refund for the diagnostic fee they charged on my AMX card (that must have been on file/then mailed me the receipt ?)
Thanks

jpohl402

^^^

See above... opinions ?

jpohl402

Well today I had the car looked at by a muffler shop.
They said the Sec. Cats appeared to be fine ?
A few welds from the custom exhaust were leaking VERY slightly, so those are being repaired - possibly that's where the problem came from ? I am having the Sec. Cats removed and replaced with Straight Pipes...
But he suggested 3 inch pipes, and I just got on here to read again, and someone stated above 3 inch pipes may cause loss of back pressure....
I have heard people go with both 2.5 and 3 inch pipes -- which is better ?
Stock is an odd size - 2.75
Thanks