[WhiteFury]

So I dropped my car to the dealer to get diagnosed the problem is in another thread that I created.

So the dealer gave me a loaner car, it's 2011 335i two-door coupe The exhaust note on this car is more growling and aggressive than my car it's not a lot louder but it's definitely a little bit louder why is this?

Is the only difference between the two exhausts that mine is an Xdrive and it has the secondary cats? So if I remove those secondary cats And replaced with straight pipe would my car sound the same? I just checked and the coupe doesn't have the 2 cats as pictured in my car (pic below)

I love how the coupe sounds!

[WhiteFury]

Here isy Xdrive 4 door exhaust. The 2 door has just straight pipe where these two fat cans sit!

[turo]

I don't think it's a coupe-vs-sedan thing, I think it's an xDrive-vs-RWD thing. Someone correct me if I'm wrong/

[SRT14PimPin07]

Originally Posted by turo

I don't think it's a coupe-vs-sedan thing, I think it's an xDrive-vs-RWD thing. Someone correct me if I'm wrong/

Yea your right....OP Take off your secondary cats and you will be happy. Plus you will get a little hp/tq gains, and it will not smell bad because your main cats will still be in tact.

[JETmn]

The coupe also does not have packing in the pipe that gets opened up in sport mode, where ours is perforated and has packing in it. Yes, the cats are an x-drive thing.

[Red_Bean_Bun]

Does the drive sedan have a valve to open as like the golf tee mod ?

[WhiteFury]

What part of the exhaust has packing in it? Yes it has the valve that opens. As far as I can see the secondary cats is the only difference.

If there is packing somewhere I'm going to try and remove it.


Why does this car have secondary cats? I don't know what awd has to do with exhaust.

[loesch]

Another thing that will change the exhaust tone is the DME, engine computer, software version. I received an update that really quieted the exhaust note. The difference might be more audible since I have deleted the muffler with an AA axle back but it was very noticeable.

[WhiteFury]

Originally Posted by loesch

Another thing that will change the exhaust tone is the DME, engine computer, software version. I received an update that really quieted the exhaust note. The difference might be more audible since I have deleted the muffler with an AA axle back but it was very noticeable.

That's weird for sure lol

[JETmn]

Originally Posted by WhiteFury

What part of the exhaust has packing in it? Yes it has the valve that opens. As far as I can see the secondary cats is the only difference.

If there is packing somewhere I'm going to try and remove it.


Why does this car have secondary cats? I don't know what awd has to do with exhaust.

The mufflers in the back have the packing in it. I plan to put header wrap around my driver's side one (open it up and put it around the pipe), so when I go in sport mode it will be quite a bit louder.

I am baffled as to why only the Xdrive has secondary cats too, doesn't make much sense. Maybe because of the slight decrease in mileage and they were trying to stay under some emissions limit?

[WhiteFury]

Originally Posted by JETmn

The mufflers in the back have the packing in it. I plan to put header wrap around my driver's side one (open it up and put it around the pipe), so when I go in sport mode it will be quite a bit louder.

I am baffled as to why only the Xdrive has secondary cats too, doesn't make much sense. Maybe because of the slight decrease in mileage and they were trying to stay under some emissions limit?

What do you mean open up the muffler?

Also what do you mean about less mileage for emission?

[JETmn]

You drop the exhaust and cut the top off the mufflers off, do you mods and weld it back up. There is a thread in the N54 section about it. Once it is reinstalled you can't tell they were messed with

AWD gets lower MPG, therefore has more emissions because of increased fuel consumption. That is the only reason I could think of why the Xdrive has more emissions than the RWD cars.