BB's and a new sound...Need some info! - The Unofficial BMW M5 Messageboard (m5board.com)

TriflowM5+M3 · 17th February 2003, 15:50

I dont know what happened this weekend but I love it...

I was down in Miami this weekend hanging out with one of my buddies and a bunch of friends and we pretty much went after each other the entire time (he has a 350Z) and when I got home from the 3 hour trip, my car has a new sound to it.

Anyone remember what the M5 Driving Experience cars sounded like? Take that rumble and sound and add it to a BB triflo system with Xpipes! At about 3K rpm it changes from low and deep with rumble to rumble city and you feel each and every rpm now. Its unreal! I dont want it to change...i was starting to think my exhaust wasnt loud enough anymore...if I had only known how to change it before, i would have.

What could have caused this sound change? I know that I was pushing her pretty hard on the ride home....a E46 M3 and I were cruising with each other on the way home @ like 110!

Any thoughts?

TriflowM5+M3 · 17th February 2003, 19:40

Time to drive the new sound!

HaroldC · 17th February 2003, 20:50

TriflowM5,

You are still breaking in the exhaust. Most think that after a few hundred miles, an exhaust is broken in and will remain to sound that way for the life of the muffler. This is not so, there is still plenty of packing material in the muffler. What happened to you is that sustained high rpm driving further burns away the remaining packing. This is most noticable on cars that are tracked, the exhaust temps are so much higher than with normal driving, that pretty much all of the material in the can is just burned off.

Even during spirited driving, the exhaust temps are not nearly as great as they are with sustained high rpms. There is even a difference with stock exhausts, when you compare a track junkie's vs. a daily driver's.

It was amazing how much my Dinan exhaust (540i) opened up after tracking it the first time. With each successive heat cycle, the sound got deeper and meaner sounding. It took about 3 days on the track to fully break in the exhaust. I can't wait to get my M3 on the track and break in the AA exhaust.

Enjoy the sound! It'll get even better!

TriflowM5+M3 · 17th February 2003, 21:27

HArold...

thanks...thats what I was thinking but I guess i was under the assumption that most of the material was already gone. This really was the first long (over an hour) drive with the xpipe on. I guess i should have done it sooner...weird thing is, it only sounds good when warmed up. Its actually back to psudo-normal bb sound when cold. I have to push her just the slightest amount to get to "roar" level

MIB · 18th February 2003, 13:38

Hey Great Post HaroldC,

That is very good information to know. Its the little things like this that you tend to overlook.

Good Job.

TriflowM5+M3 · 18th February 2003, 16:10

I knew that after a while the sound material would slowly go away but i didnt realize that I had to fully break in the exhaust...after my numerous trip to orlando (about and hour or so away) i figured that it was broken in. Today the tech at the dealer got to feel the new sound...he loved the old sound and just about dropped his jaw when she was all warmed up. God i love the new sound!

TriflowM5+M3 · 19th February 2003, 00:25

Its gone...i leave it at the dealer for one day and now my wonderful sound is gone, whats not gone are the 30 miles that my dealer put on my car!!! BAstards!

HaroldC · 19th February 2003, 04:37

What did they do?

Your sound should not have changed from just a visit to the dealer. Unless they replaced something in the exhaust system: cats, headers, resonator, or muffler.

Did you get the exhaust warm enough?

MIB · 19th February 2003, 05:12

Maybe they loved the sound so much, they stole your exhaust, and replaced it with a brand new one.

You have to break it in again all over.

Sorry, didn't mean to laugh. I'm interested to hear what happened.

TriflowM5+M3 · 19th February 2003, 15:38

Ok, This might be a stretch but.

Yesterday morning when I took my car to the dealer, at a light the rpms just dropped out the floor and the car got that mean sound! It hasnt done it since getting the car back so I am starting to think that it might be a vanos problem. I remember people talking about how the car would just drop about 10 octaves and have a totally different personality.

Last night I drove her up and down the interstate at 90+ to warm up the exhaust to what I thought would be good. I also kept her in 5th to make sure that she was at 3K rpm as well.

The sound is now gone and I am meaning to call the dealer to ask them why 30 miles were put on my car for an oil change and some brake pad switching that never even took place!