135i: Some questions to the exhaust systems (135i - N54/N55/Performance)

[Saiba]

Hi guys

The actual exhaust system of my 135i (N55 with DCT) is:
N55 stock Midpipe // Performance Y-Pipe // Performance Exhaust

While many would like to have this setup, I only can enjoy it when it doesn't drone all the time at a low frequency(bass).
It drones up to 2300rpm. Therefore it drones all the time on the speed limited Autobahn (highway) since the 7th gear is in. It might sound great from outside, but the low frequency drone isn't fun inside. It's rather disturbing for me.

I rated the sound as almost perfect when I've testdroven a stock 135i (N55) from a seller. It was quiet when I didn't push it, it was quite on the Autobahn in the 7th gear. But it was loud and meaty enough when I did WOT or activated the sport-mode with the sport-button right next to the DCT gearshift.

Now I'm thinking about to downgrade my actual exhaust system My only problem is: I've bought my car without the stock exhaust system. But maybe I can get a N54-resonator and a N54 exhaust. So here are my questions:

Are these two following setups possible / doable?
Setup 1: N55 stock Midpipe // N54 resonator // Performance Exhaust
Setup 2: N55 stock Midpipe // Performance Y-Pipe // N54 stock Exhaust

I'm interested in avoiding loud exhaust noises while cruising on the highway or in the city. So which one of these two approaches would be probably the best solution for my taste?
My thoughts about these two:
Setup 1: I get a resonator, but I have no flap at the exhaust.
Setup 2: I get a flap at the exhaust, but will it do it without a resonator? And will a the flap from a N54 exhaust work with my N55?

The worst case-scenario would be the downgrade to: N55 stock Midpipe // N54 resonator // N54 stock Exhaust
By the way, are the N54 resonators and exhaust exactly the same like the N55 one's? Or are there minor differences?

I know, a LOT of questions. But there seem to be a lot of guru's here as well

[ShocknAwe]

Skip the flap, get a resonator. Or two depending on what you get.

[Saiba]

Thanks for your comment. Can you describe / explain your approach please?
And why two resonators? Which resonator can I add extra? There's only one resonator between midpipe and the pipe to the exhaust (which also has a resonator).

[Dackelone]

First, welcome to 1Addicts @Saiba


I'm curious as to why the other 135i you drove with the same setup sounded better? Did it not drone also ? Or did you not drive it much at low revs 130 kph ?


I have the Performance Exhaust (ESD & Y-pipe) on my 135i (N54). I really LOVE the sound! It does sound better from outside the car, though. Inside's not bad either, but everyone tells me how GOOD it sounds when I blast past them!

I will say that once I put on about 10K kms on the PE... the sound got deeper and it had less rasp or drone. The exhaust needs time to carbon up some.

How many kms have you driven with your PE ?

That said, the PE is louder on a N55. That's because the N54 has four cats, vs the N55's single cat.

N54 has two main cats(Kat) and two secondary cats in the mid pipe. The N55 only has one cat on the down pipe. Thats why the N55 exhaust is slightly louder, especially at WOT(full gas).

I think what I would recommend for you to do - is to delete the y-pipe from your PE system. You could purchase some N55 mid pipes and install them. By adding the resonator you will get rid of most of that drone.

PE system...


N55 mid pipe RIGHT, N54 mid pipe LEFT (with secondary cats).



Dackel



PS: here is my thread on installing the N55 mid pipes on my N54. I ended up taking them off bc they were too loud for my taste. Thats when I went with the PE. I'm happy with my PE.

DIY installing N55 mid pipes on a N54...
http://www.1addicts.com/forums/showthread.php?t=797160

[Saiba]

Thank you, Dackel.

I guess it was better to drive because everything was on stock. And it also had the flap at the exhaust.
Mine has the PPK, just to mention it.
I also have to mention that I am sensitive to loud noises, so maybe other people would rate it as loud, but not annoying while I rate it as annoying loud. Most time when it's getting loud, it's just getting annoying loud without much drone. Just to specify that.

However! What should I do if I can get a midpipe resonator (no matter from N54 or N55) and it is too short? There's probably no proper solution for that, right?

Another question: If I try the combo "N55 stock Midpipe // Performance Y-Pipe // N54 stock Exhaust", will I get back the flap function?
This combo would 100% fit, since the Performance Y-Pipe will match the stock exhaust. So can't it be that this solution will solve the loudness problem?

Further tips by anyone are much appreciated

[Dackelone]

Originally Posted by Saiba

Another question: If I try the combo "N55 stock Midpipe // Performance Y-Pipe // N54 stock Exhaust", will I get back the flap function?
This combo would 100% fit, since the Performance Y-Pipe will match the stock exhaust. So can't it be that this solution will solve the loudness problem?

Saiba, there are two versions of the PE(Performance Exhaust). One for the US market and one for Europe. I think the only differences are noise levels to meet TUV standards.


Exhaust system = Auspuffanlagen
Axle back exhaust (rear muffler) = Endschalldämpfer(ESD)


I was suggesting for you to replace your mid pipe(now that you have the PE y-pipe installed) and run a standard N55 mid pipe. The standard N55 mid pipe has the rear resonator which will really quiet the exhaust tone.

IF that is still too loud for your tastes... maybe have two additional resonators installed on your mid pipe(before the rear resonator). Or even go back to the standard 135i exhaust system. ?

Dackel



Performance Exhaust: new in the box


135i standard exhaust(left) PE (right) see how there is no flapper valve on the PE!


another PE


PE y-pipe resonator delete


resonator cut off...


original N55 mid pipe. The PE's y-pipe replaces this resonator with a straight thru pipe! (loud & gives you those pops!)

[ShocknAwe]

Hey there, sorry to sketch out on your question. The forum didn't send me a notification of your response and I forgot to check.

Like Dackel has posted, the N55 midpipe has no cats and a resonator, and if you have the PE Y-pipe you have no resonator at all. My approach, if this is too droney and raspey for your taste, would be to add a bullet resonator (a-la vibrant 12 inch) to the positions where the cats are located on the N54 midpipe. I would add two so that you have one on each pipe.

The other option is as Dack said, get a N55 midpipe for the Y-pipe resonator.

[e82passion]

I would personally go for the resonator install. The stock exhaust with the flapper isn't going to make as big a difference with regard to drone.

[Saiba]

Hi guys. Thanks for your recommendations. Much appreciated!
I'll have to look for a midpipe with the resonator then, since it sounds like the resonator would matter a lot for the loudness and drone, according your informations
Just for your information: I purchased my car with the Performance exhaust system, therefore I don't have any stock midpipe resonator and stock exhaust.

@e82passion: Are you sure that the flapper doesn't make a big difference?
I find the flapper interesting as an additional noise canceler for cruising on the Autobahn / highways.

However, as long as the loud drones disappear with the midpipe resonator, I really may stick with the Performance exhaust.

[Dackelone]

Originally Posted by Saiba

Hi guys. Thanks for your recommendations. Much appreciated!
I'll have to look for a midpipe with the resonator then, since it sounds like the resonator would matter a lot for the loudness and drone, according your informations
Just for your information: I purchased my car with the Performance exhaust system, therefore I don't have any stock midpipe resonator and stock exhaust.

@e82passion: Are you sure that the flapper doesn't make a big difference?
I find the flapper interesting as an additional noise canceler for cruising on the Autobahn / highways.

However, as long as the loud drones disappear with the midpipe resonator, I really may stick with the Performance exhaust.

^^I also agree with @e82passion the rear flapper won't make that much difference. It's all in that rear resonator.

IF you look at some old PE installs(DIY's) you will see a lot of guys first installed only the rear(ESD)muffler from the PE. They did half the install really. I think they were expecting more "noise" or "music" from just the rear (PE)muffler. So after a few days they got "down and dirty" and installed the PE's y-pipe as well. THAT is what makes the exhaust loud(er).





E82 135i BMW Performance Schalldämpfer-System
http://www.realoem.com/bmw/showparts...&fg=95&lang=de


Since you have a N55 car... you only have ONE kat(catalizer), then its all straight mid pipes to your PE muffler(ESD). By getting rid of the rear y-pipe. you will "quiet down" your exhaust. Maybe that will be enough for you. IF not... you shouldn't have a hard time finding another 135i owner who would like to swap exhaust.

Good Luck,
Dackel




PS: this thread might be of help too. Even though you don't own a 1M...

http://www.1addicts.com/forums/showthread.php?t=759270

[e82passion]

Originally Posted by Saiba

@e82passion: Are you sure that the flapper doesn't make a big difference?
I find the flapper interesting as an additional noise canceler for cruising on the Autobahn / highways.

Yep. You can't control the flapper actuator anyways. It's controlled via the exhaust pressure. The only thing I've noticed with the flapper delete is I get slightly less low end torque. When I first installed the PE, I was afraid of the drone so I first installed the PE muffler only. There was barely any noticeable difference in the sound. Then I went ahead to delete the resonator and go with the Y-pipe as well. The drone to me is acceptable, however, since I'm running the stock N54 secondary cats still, it will be less loud than the N55 without the secondary cats. But point being that the resonator made a huge difference in sound.

[Robmaster]

@Dackelone:
Did you know the diameter of the exhaustpipe just befor the muffler?

[Dackelone]

Originally Posted by Robmaster

@Dackelone:
Did you know the diameter of the exhaustpipe just befor the muffler?

It's right around 60mm's. Actually, I think it's 58mm's - that is what the O.D. of the mid pipes were.