Exhaust diameter: Sound difference
 

1999 A4 2.8 Quattro

Hey guys,

A few years ago I had a custom 2.5" piping cat-back system welded in (stock is 2.00") and just put on a Magnaflow 14815 exhaust on. It's not my first muffler swap, and i like the way it sounds, but it's still a tad loud for my taste, plus there is an obnoxious rattling coming from somewhere, no matter what exhaust i have. I know it's not my cats (those are new) and I just changed my flex pipes so I know it's not those. 2 Questions. First, will going back to 2" make it quieter? And does anybody have any experience with the rattling? I've had 4 mechanics look at it and nobody has a clue! Thanks a lot!

even though you say cats are new, how old are they? its possible if theyre not genuine audi cats they will go bad within a year and cause the sound your experiencing, its also possible the heat shield around your exhaust is also the cause of the sound

ive got a 99 a4 2.8 Quattro with 2.25" cat back piping(resonator delete) and a Magnaflow 14816 muffler and it sounds good, but has a LOT of drone at cruising speeds(55mph etc) im putting a magnaflow resonator back on it to get rid of the drone heres a link to a vid on my car...

http://www.youtube.com/watch?v=bSMxEh-3sZk

http://www.youtube.com/watch?v=6KG64Hk_wkY

as for the rattling sound im not sure what it could be but the heat sheilds could be it like b5_audi_lover previously stated, and going with smaller piping could quieten it down but it might make it soound raspy idk though. i thought stock piping for our cars was 2.25" though?

Yea, I saw your video when I was looking at the muffler before I got it. It sounds great on your car. And sounds kind of similar on mine, except for the high-pitch rattling. I should take a video. And YES, the droning sucks, especially accelerating in higher gear. Resonator is a good idea. And I've heard that about going to smaller pipes, that it may quiet it down, but it will make it higher-pitched. I do want it quieter, but I like the deeper sound.

Regarding the cats, funny you say that. I found out the cats that I put on (Magnaflow 54306) are obviously not only after market, but the WRONG ones for my car. I am in the middle of trying to claim a warranty with Magnaflow (to get Magnaflow 46704, OEM is so expensive)because someone told me it was the right one.

As far as the heat shields go, I have looked at that, and I'm almost positive it's not that.

yea those mufflers sound really good on our cars, but the Cats might be your problem if you accidentally put the wrong ones on, hope ya get it fixed, post a video up here of how your car sounds

Which Magnaflow resonator are you getting? I was doing some reading and a few people said bad things about their resonators, and recommended Dyomax... Any thoughts?

i just had a Magnaflow 10426 resonator, 2.5 inches in diameter with my 2.25 inch piping, just had it installed today, and the drone was halfway or more eliminated, and got rid of the raspy sound on cold startup, and isnt as obnoxiously loud and still sounds good with that deep throaty tone, im very pleased so far with it. if i had a video camera id post a vid

Cool thanks. I'll prob do the same. The droning is pretty bad. I'll try to post a video when its in.

Wow, just put the Magnaflow Res and it sounds SO much better. Still sounds really good but without the ridiculous loudness and droning. Perfect as far as I'm concerned! Thanks for the advice bud!

no problem man haha glad to help