[fisc0h]

Hi all,

I have a 2011 335 x-drive and, therefore, have secondary cats on my midpipe. I am in the market for the BMW performance exhaust. The PE for the N55 is the mufflers only (part # ) However, if I order the N54 PE (which includes the midpipe, I believe), does this effectively delete the secondary cats? or is this incorrect/no benefit?

Thanks!

[j23a45m]

sounds correct, but looking here I guess thats false

http://www.e90post.com/forums/showthread.php?t=687672

[pocoyo_3]

I'm selling a barely used (used for under 300 miles) N55 performance exhaust. Bought it a month ago and did not like it so I had my original exhaust fitted back. Let me know if you are interested in buying it.

[fisc0h]

Originally Posted by j23a45m

sounds correct, but looking here I guess thats false

http://www.e90post.com/forums/showthread.php?t=687672

Thanks for the reply, but that's for a e92, which do not have secondary cats. From what I've read all X-drives and all n54 E90 have secondary cats. I'm unsure if the midpipe that comes with the N54 E90 PE eliminates these.

[evo335xi]

I thought that the e92's only switched the mufflers and the e90's had an extra pipe to remove the resonator? I could be wrong though.

[fisc0h]

After much research/reading, I finally came to a conclusion.

- All 335i X-drive E90/E92 (both N54 & N55) have secondary cats
- 335 N55 E92/E90 (RWD) have no secondary cats
- Only N54 E90s have the resonator on the rear section of the exhaust (from the secondary cats, back)
- 335 (X-drive & RWD) N55 replace this resonator with the X-pipe (also on N54 E92).

So, the "midpipe"/X-pipe/Y-pipe that comes with the E90 N54 BMW Performance exhaust eliminates only the resonator (it does not eliminate the secondary cats). Therefore, this is of no benefit to any E92 or N55, as they already have this pipe from the factory.

Hope this helps someone

_____Stock N54 E90 Exhaust with secondary cats + resonator_____




_____X-Pipe that only comes with E90 N54 Performance Exhaust Kit_____




_____Stock N55 E90 X-drive Exhaust: Secondary cats, with X-pipe, No Resonator_____




_____Stock N55 E92 Exhaust: Catless, no resonator, X-pipe_____

[WhiteFury]

Why does the Xdrive have these secondary cats?

So if i was to have a shop weld into place some pipe and ditch the secondary cats my car would sound identical to a 2 door coupe? Or would it be louder?

I want to have this done but will this make my check engine light come on or is the primary cats on the down pipe the actual emissions part?

[PNWN54]

Sorry to resurrect an old thread but I'm being offered N55 Performance Mufflers for a N54 E90. I already bought an X pipe to replace my midpipe.
The big question is:
are N54 PE mufflers and N55 Mufflers the same?

Please someone chime in. This thread has been very helpful so far! Thanks!

[evo335xi]

I believe they are the same!

[PNWN54]

Originally Posted by evo335xi

I believe they are the same!

Hey Evo, I really hope so! It looks like most of the change was a little further down and closer to the engine. I called the dealer and asked the same question but was only told they are two different parts. Hoping for some more people to chime in.

[fisc0h]

Pretty sure the mufflers are the same. Only difference is the PE for the N54 comes with the X pipe

Originally Posted by Rock&Roll

Sorry to resurrect an old thread but I'm being offered N55 Performance Mufflers for a N54 E90. I already bought an X pipe to replace my midpipe.
The big question is:
are N54 PE mufflers and N55 Mufflers the same?

Please someone chime in. This thread has been very helpful so far! Thanks!

[Ramsey]

Originally Posted by Rock&Roll

Hey Evo, I really hope so! It looks like most of the change was a little further down and closer to the engine. I called the dealer and asked the same question but was only told they are two different parts. Hoping for some more people to chime in.

There is a 56 page thread under DYI that addressed this. Search the general forum, search for 2.5 pipe and it will give the full thread that includes how to modify stock OEM N54 and N55 exhaust to sound like PE.

Below answer on x pipe and resonator is accurate, however the inside of PE mufflers are different from stock. The tubes inside the stock mufflers are perforated and have a canister. PE mufflers have straight pipes, not perforated. Also, less packing(sound absorbing) material inside PE muffler.

Check the thread I am referring to.

[PNWN54]

Originally Posted by Ramsey

There is a 56 page thread under DYI that addressed this. Search the general forum, search for 2.5 pipe and it will give the full thread that includes how to modify stock OEM N54 and N55 exhaust to sound like PE.

Below answer on x pipe and resonator is accurate, however the inside of PE mufflers are different from stock. The tubes inside the stock mufflers are perforated and have a canister. PE mufflers have straight pipes, not perforated. Also, less packing(sound absorbing) material inside PE muffler.

Check the thread I am referring to.

Hey Ramsey, I have been following that thread for a while and I'm very familiar with the mechanics of modifying the OEM mufflers to sound like the PE exhaust. I was quoted by most shops outrageous numbers and it didn't make any sense in doing this to my stock mufflers.

Since then I bought the N55 mufflers and added them with a custom welded x pipe. Sounds really great to me and I very much like it.

Some people described the exhaust note on my car to be very exotic. One buddy said it reminds him of his modified Yamaha R6 and some others said it sounds like a mini Ferrari at WOT.
I'm quite happy.

[Jsoboti]

Originally Posted by pocoyo_3

I'm selling a barely used (used for under 300 miles) N55 performance exhaust. Bought it a month ago and did not like it so I had my original exhaust fitted back. Let me know if you are interested in buying it.

Still selling?

[Schmidty335i]

i have a E92 with JB4 if i get a catless DP will i have any issues with performance or check engine lights, since there are no secondary cats? or will i only have to worry about emissions? thanks!

[Knonsense]

Originally Posted by Schmidty335i

i have a E92 with JB4 if i get a catless DP will i have any issues with performance or check engine lights, since there are no secondary cats? or will i only have to worry about emissions? thanks!

n55's have wideband O2 sensors - you don't need a cat for the car to cope -> no issues with performance. i'm 90% sure the n54s have wideband O2s, too.

you can get mini-cats to fool the O2 sensors on n54/55 ( http://www.e90post.com/forums/showthread.php?p=15962330 ) but you need 90 degree elbows for the (now too long) sensor assembly to clear the firewall.

[PNWN54]

Originally Posted by Schmidty335i

i have a E92 with JB4 if i get a catless DP will i have any issues with performance or check engine lights, since there are no secondary cats? or will i only have to worry about emissions? thanks!

Your jb4 has auto clear which will enable a "downpipe fix".

[Schmidty335i]

Originally Posted by Knonsense

n55's have wideband O2 sensors - you don't need a cat for the car to cope -> no issues with performance. i'm 90% sure the n54s have wideband O2s, too.

you can get mini-cats to fool the O2 sensors on n54/55 ( http://www.e90post.com/forums/showthread.php?p=15962330 ) but you need 90 degree elbows for the (now too long) sensor assembly to clear the firewall.

Nice i wasnt aware that they had Wideband O2 sensors i just ordered a VRSF Catless DP. My next question is am wondering if my stock exhaust is even worth replacing since it doesnt have secondary cats it should flow pretty well as is right? iam thinking my next step should be CP or FMIC. Any suggestions, like i said i already have a BMS intake and JB4 with a DP on the way.

[Knonsense]

Originally Posted by Rock&Roll

Your jb4 has auto clear which will enable a "downpipe fix".

the jb4 "fix" just stops the CEl from appearing. you won't pass an OBD emissions inspection.

Schmidty, the stock exhaust will flow fine. if you have the 6at, get the Alpina flash next. CP would probably be before FMIC, that's at least my intended path.

[Schmidty335i]

Originally Posted by Knonsense

the jb4 "fix" just stops the CEl from appearing. you won't pass an OBD emissions inspection.

Schmidty, the stock exhaust will flow fine. if you have the 6at, get the Alpina flash next. CP would probably be before FMIC, that's at least my intended path.

i just got my emissions test done so i should be good for awhile, not looking foward to having to swap the cat and catless pipes for future test. owell haha. I have a manual trans so i guess my next step will be CP and then FMIC. thanks for all the info Knonsense!

[Knonsense]

cheers