Z4M Stock exhaust modification.

[Kgolf31]

Originally Posted by BTM

There are 2 cats in your headers, and 2 secondary cats (with no O2 sensors) in the section between the headers and the xpipe

Replacing the Xpipe doesn't delete any cats. What I did also didn't change any of the emissions equipment since there are no sensors there. You'd have to take the pipe off the car to know there was nothing inside the cat

Gotcha, I just looked up diagrams and it answered my own question. Sorry for the stupidity.

I may considering going an X-Pipe and Magnaflow Muffler Route as well, it's a cheaper alternative to these $1k can only mufflers.

Do you have any videos?

[BTM]

Here is one but kinda shitty

I have a contour now that mounts better and takes better videos than gopro. If it stays warm this week I'll take the car out and get a better one.

[BTM]

I might be selling just the cans soon if your interested. I'm looking at going muffler delete to save more weight

[Kgolf31]

Originally Posted by BTM

I might be selling just the cans soon if your interested. I'm looking at going muffler delete to save more weight

Let me know, if they're in my price range I may be interested.

[zubydafa]

Originally Posted by BTM

With the stock exhaust, it's just like I said, sounds like stock just louder. Same tone, no drone, etc.

The exhaust I have now (BMS xpipe Magnaflow mufflers) I bought from a local forum member so I had the luxury of going for a ride in his car to hear it and see if I liked it. I ended up buying it, and on my car, it is a little raspier and certainly louder than it was on his car. Given the only difference between our setups was my secondary cat delete, I'd have to attribute it with the difference in sound. FWIW, it's louder than RPIs, so if you're worried about going too loud, I would mess around with the xpipe and mufflers first, because once you gut the cat it's gone and not cheap to replace.

I did also end up using a minimal amount of dynamat on the floor of the trunk to absorb some sound and vibration.

you have the secondary cats removed along with an xpipe and mufflers...i can see how that would get loud

i'm just looking at getting an xpipe and the secondary cat removal and calling it a day. lot more research to do though. thanks for your reply

[BIMMERGUY91]

BTM any drone with that set up? I also really like the stock sound but wish it was just louder. I have been thinking about doing headers simply because they are a great performance mod for this car do you think that alone would increase sound enough for me?

[BTM]

Originally Posted by BIMMERGUY91

BTM any drone with that set up? I also really like the stock sound but wish it was just louder. I have been thinking about doing headers simply because they are a great performance mod for this car do you think that alone would increase sound enough for me?

With the stock exhaust and cats gutted there was no drone. With the setup I have now there is certainly drone, especially in the 2-2.2k range. Cruising on the highway turning just around 3k in 6th is actually not bad though. It's not quiet, but it's not drone either. As far as headers with the stock exhaust goes, I have no personal experience.

In the coupe, I've noticed that what you have in the hatch makes a difference. For example, going to an autox one time, we put the cooler right on the floor of the trunk, and this seemed to amplify the noise. On the way back I laid my jacket across the floor and placed the cooler on that, and it was much better.

[BIMMERGUY91]

Yeah I am going to be putting dynamat in my trunk to quite things down

[EenyBear]

You know, just having the "///M" carpet in the back makes a noticeable difference in road noise in my MC. Perhaps it's an alternative to Dynamat that actually looks good too.
$0.02