135i exhaust mod

[Gedi89]

Hi there new to the 135i world and totally love the car only owned it a couple months now and would like a little bit more noise without sounding stupidly loud I have completely stock exhaust still with cats in place it's a 08 n54 any suggestions and pics would be great
Many thanks

[Afam28]

Try the golf tee mod...(slightly more noise)
Or...
Catless downpipes, mid pipes and axle back exhaust and wake the neighbors...!

[Gedi89]

Have tried the golf tee mod makes no difference to me I would like a slightly more aggressive noise without being really loud like a boy racer in his first Citroen scrapso so to speak have been reading about the pe mod but have only really seen it on the 335i what I believe has a different muffler as it has a twin rear silencer

[Afam28]

Well, hopefully someone can chime in a shed some more light for you...
I've heard of the PE mod but not much more, so I can't help in terms of whether it's a feasible route for you...

[Thunderguts]

Originally Posted by Gedi89

Hi there new to the 135i world and totally love the car only owned it a couple months now and would like a little bit more noise without sounding stupidly loud I have completely stock exhaust still with cats in place it's a 08 n54 any suggestions and pics would be great
Many thanks

So is a new exhaust out of the question? I assume you are looking for low-cost modifications rather than a replacement.

[Gedi89]

Thanks for the reply and yes a low cost mod would more suit me as I'm capable of welding and doing the kind of mod that I've seen people calling the pe mod but just haven't really seen any specific one for the n54 135i the ones I've seen all seem to be different and I would want to keep it looking original from the outside as I really like the standard gloss black tail pipes I already have on the car any recommendations or a link to a decent pe mod would be appreciated

[Soterios]

A new axle-back. Unless you want to cut open your muffler, remove some baffling, and close it back up, I'm not sure what other 'cheap' options you'll have. At the end of the day it's just some pipes and the only things really cutting down noise are the cats and the muffler.

I have an N55 car, so my mid pipes are just pipes, but perhaps that would be an option? I know there was a thread a while back about someone installing N55 mid pipes on an N54 car.

[Gedi89]

The n55 miss will be on my list of to do bits to the car but I can't seem to find any as of yet on eBay

[duder13]

Originally Posted by Gedi89

Thanks for the reply and yes a low cost mod would more suit me as I'm capable of welding and doing the kind of mod that I've seen people calling the pe mod but just haven't really seen any specific one for the n54 135i the ones I've seen all seem to be different and I would want to keep it looking original from the outside as I really like the standard gloss black tail pipes I already have on the car any recommendations or a link to a decent pe mod would be appreciated

IIRC, the PE mod for the N54 is tougher, because the pipes in two chambers have perforations. AFAIK, the N55 muffler has perforations in the pipes of only one chamber, so the PE mod would be much easier. I plan on doing it to my N55 soon.

[Gedi89]

I don't mind cutting and welding it up if I'm going to do it would rather cut and fabricate what I've got rather than buying another one and still cutting and fabricating was just wondering though as there's soo many people putting pics up of that are all different was just looking for a cut open pic of the n54 muffler really
Thanks for the reply's

[myoneseries]

I did the PE mod and it sounds really good under 4k. it gets real tinny above that and doesn't sound good imo. I have put mine back to stock since I am catless and manual.

Inside the muffler there is a wye that in the n55 cars is solid and the n54 is perforated. All else being the same. Most guys just cut the center section and get some stainless hose clamps and header wrap. That way it is reversible.

The muffler is stainless so if you cut it open and want it pretty, you gotta weld for stainless. Otherwise just paint it.

There is also a resonator on the mid pipe you can weld a pipe inside of to get rid of the resonator without destroying the factory midpipe. the PE exhaust comes with a resonator delete.

And if you have all the catalysts it probably would sound pretty good, but if you really dig into it you will hear similar complaints as mine. keep in mind the n55 cars have no secondary cats either.

there is a really good write up on this forum for this whole process. 90% of what I am telling you is from this forum and I don't mean to take credit.

[duder13]

Originally Posted by myoneseries

I did the PE mod and it sounds really good under 4k. it gets real tinny above that and doesn't sound good imo. I have put mine back to stock since I am catless and manual.

Inside the muffler there is a wye that in the n55 cars is solid and the n54 is perforated. All else being the same. Most guys just cut the center section and get some stainless hose clamps and header wrap. That way it is reversible.

The muffler is stainless so if you cut it open and want it pretty, you gotta weld for stainless. Otherwise just paint it.

There is also a resonator on the mid pipe you can weld a pipe inside of to get rid of the resonator without destroying the factory midpipe. the PE exhaust comes with a resonator delete.

And if you have all the catalysts it probably would sound pretty good, but if you really dig into it you will hear similar complaints as mine. keep in mind the n55 cars have no secondary cats either.

there is a really good write up on this forum for this whole process. 90% of what I am telling you is from this forum and I don't mean to take credit.

Interesting about the sound. Did you do the resonator pipe, or just the muffler weld?

[myoneseries]

Originally Posted by duder13

Interesting about the sound. Did you do the resonator pipe, or just the muffler weld?

Just the muffler. It was substantially louder with muffler. It basically makes it a straight through muffler.

[duder13]

Originally Posted by myoneseries

Just the muffler. It was substantially louder with muffler. It basically makes it a straight through muffler.

Thanks. Did you have any drone issues, or just increased volume? I was planning on doing the mod this week, but now I'm a little concerned. Granted, I was going to just have the three big holes plugged, rather than the pipe with the small holes.

[myoneseries]

Originally Posted by duder13

Thanks. Did you have any drone issues, or just increased volume? I was planning on doing the mod this week, but now I'm a little concerned. Granted, I was going to just have the three big holes plugged, rather than the pipe with the small holes.

It droned at I think 24-2500 in high gear. Around town was fine.

Really sounded good around town. Wot runs was what sounded awful. Tinny and deafening but I was catless.

In the other forum or even the 1m forum people were swapping in some resonators in place of the secondary cats.

The pipe without the 3 holes I think was still perforated in the pe. I never welded it up just the wye in the muffler and the larger 3 holes. Welding up the wye made it have gurgle and pop but it was hard to hear in the car. Welding the 3 holes made it loud. I left the flapper hooked up most of the time too.

[myoneseries]

Originally Posted by myoneseries

It droned at I think 24-2500 in high gear. Around town was fine.

Really sounded good around town. Wot runs was what sounded awful. Tinny and deafening but I was catless.

In the other forum or even the 1m forum people were swapping in some resonators in place of the secondary cats.

The pipe without the 3 holes I think was still perforated in the pe. I never welded it up just the wye in the muffler and the larger 3 holes. Welding up the wye made it have gurgle and pop but it was hard to hear in the car. Welding the 3 holes made it loud. I left the flapper hooked up most of the time too.

Take the muffler off and drive around the block. That's gonna be a little louder but almost the way the exhaust will be after the mod

[Edrift]

Originally Posted by Gedi89

Hi there new to the 135i world and totally love the car only owned it a couple months now and would like a little bit more noise without sounding stupidly loud I have completely stock exhaust still with cats in place it's a 08 n54 any suggestions and pics would be great
Many thanks

If you are on a budget follow my guide here:

https://www.1addicts.com/forums/showthread.php?t=1654887

I have the e88 n54.

I just opened up the second chamber of the muffler today and repacked that will al foil instead of the fibreglass.
Not stupid loud nor does it drone.

All done for about $US10.
If you can weld then it'll be cheaper.

[6ixSpd]

Best $ I've spent on this car.

Had an exhaust shop open up the top and bottom and weld shut both pipes in the mid-section(one with 3 large holes and another with smaller perforated holes). It sounds awesome, and zero drone! Perfectly civilized when it needs to be.

I'm considering removing the resonator for a little more volume in normal driving. Anyone done that with an N55?

[dtla1]

Originally Posted by 6ixSpd

I'm considering removing the resonator for a little more volume in normal driving. Anyone done that with an N55?

I think removing the resonator would be the same as installing the Y-pipe from the Performance Exhaust.... so yes, I would say there are quite a few people who have done that?

[duder13]

Originally Posted by myoneseries

It droned at I think 24-2500 in high gear. Around town was fine.

Really sounded good around town. Wot runs was what sounded awful. Tinny and deafening but I was catless.

In the other forum or even the 1m forum people were swapping in some resonators in place of the secondary cats.

The pipe without the 3 holes I think was still perforated in the pe. I never welded it up just the wye in the muffler and the larger 3 holes. Welding up the wye made it have gurgle and pop but it was hard to hear in the car. Welding the 3 holes made it loud. I left the flapper hooked up most of the time too.

Gotcha. Being catless is a pretty big difference.