[JJH]

I am trying to understand the OEM exhaust system on the E92 335i in the hope it helps me decide on an aftermarket one for my car.

I plan on catless DPs and will retain the secondary cats section. I am wondering whether to replace the centre section/muffler together with the rear section; or just the rear section. The aim is to achieve the best performance gain, understanding that I am retaining the secondaries.

The diagram below shows the factory system, as I understand it for the E92, which has 4 separate sections. Going left to right are the sections from the front to rear of the car.



Am I correct in saying that item # 1 is the balance pipe between the left and right side of the system? Seems to me the BMW PE system is also set up this way.

Is there any other balance pipe in the system, perhaps in the centre section as part of the muffler, # 2 in the diagram?

How important is it to have a balance pipe in the system?

Thanks and cheers,
Jon

[pavo335]

Originally Posted by JJH_335

I am trying to understand the OEM exhaust system on the E92 335i in the hope it helps me decide on an aftermarket one for my car.

I plan on catless DPs and will retain the secondary cats section. I am wondering whether to replace the centre section/muffler together with the rear section; or just the rear section. The aim is to achieve the best performance gain, understanding that I am retaining the secondaries.

The diagram below shows the factory system, as I understand it for the E92, which has 4 separate sections. Going left to right are the sections from the front to rear of the car.



Am I correct in saying that item # 1 is the balance pipe between the left and right side of the system? Seems to me the BMW PE system is also set up this way.

Is there any other balance pipe in the system, perhaps in the centre section as part of the muffler, # 2 in the diagram?

How important is it to have a balance pipe in the system?

Thanks and cheers,
Jon

What other mods do you have and are planning, there are lots of other mods that offer better value

[Zen]

I had my PE installed at Advan this morning. [Nice chatting with you Peter, and big thanks to Chris and another guy in the shop (sorry didn't catch your name!) for installing it ]

I'm not too sure if this answer your question, but here is the stock exhaust image..



The balance pipe #1, for stock seems to be welded to and clamped for the PE. Yes they seem to have a similar setup, but the noise it generate is so much louder.

[_ink]

Originally Posted by Zen

I
The balance pipe #1, for stock seems to be welded to and clamped for the PE. Yes they seem to have a similar setup, but the noise it generate is so much louder.

The increased noise is due to the internal baffling that has been used in the PE.

[_ink]

Item 1 is the only balancer apparent in the stock system.

Most Aftermarket systems remove the mid muffler, however there would be no gains attributed to that.

[DR-JEKL]

From what research I have done a 'full' system only adds minimal hp (10-20HP at most) and is only mainly done for acoustics.

The 335i must be the only turbo car that I know of that isn't transformed with an aftermarket exhaust which must be why must of the big name co's just offer a rear section.

The best sounding N54 I have heard to date is ZUZU's 1M which has a meisterschaft straight pipe rear section, which kinda has me in two minds atm to purchase a cheap renntech full system or get a custom straight pipe fabricated... Something like the HPF setup:



The balance pipe which interconnects the two mufflers AFAIK is just a DB killer?:

[sbce90]

You're thinking too much.

catless dp + BMW PE = done

[JJH]

Originally Posted by sbce90

You're thinking too much.

catless dp + BMW PE = done

Ha! Yeah ... I think you may be right on that to some extent!

The question of balance pipes just had be stumped. It is usually important in a non-turbo car situation because, as I understand it, it is there to balance the exhaust gas pulses in a twin system. No idea if it is critical on a turbo car. The fact the OEM and BMW PE systems have it makes me think that is a yes. I am considering replacing the centre section muffler with an X-merge which will have a balance effect and possibly individual Supersprint rear boxes.

Or maybe just go with sbce90s suggestion of PE/DPs instead and be done with it!

Pavo335 - Only mod so far is a Cobb AP reflash, next will be AR DPs. Then considering charge pipe/DV, FMIC and then exhaust.

[Stuart@BMRAutowerkes]

Change the rear section of the exhaust.

Alan lets hear some sound clips of your car or bring it to the next meet so everyone can hear it in person

[Gemballa1980]

Stupid question (or is it?) but wouldn't the balance pipe which interconnects the two mufflers on a standard exhaust be there for when the exhaust flap is closed on the LHS muffler - to help reroute the gasses?

Does the PE have a flap in the LHS muffler as well?

[DR-JEKL]

See those series of small holes in the internal balance pipe, that is to dampen certain unwanted frequencies from being heard inside the cabin.

You will find in a PE that there will still be a balance pipe yet it has no holes and less packing in the muffler section (steel wool type packing you may have seen in some exhausts) which means > DB.

[_ink]

Originally Posted by Gemballa1980

Stupid question (or is it?) but wouldn't the balance pipe which interconnects the two mufflers on a standard exhaust be there for when the exhaust flap is closed on the LHS muffler - to help reroute the gasses?

Does the PE have a flap in the LHS muffler as well?

The PE eliminates the flap. I believe the balancer pipe helps with both harmonics and the flow.

[eriktufa]

In nutshell, you won't get much gain from exhaust mod except if you remove that secondary cat?

Btw, I am one of XXX people that fail to feel HP gain from adding DP.

Exhaust mod = waste of money? thoughts?

[Zen]

Originally Posted by bmroxm5

Change the rear section of the exhaust.

Alan lets hear some sound clips of your car or bring it to the next meet so everyone can hear it in person

Sure, I will get some clips later in the week.. Started it up this morning and god damn it is loud when its cold..

[JJH]

Originally Posted by eriktufa

In nutshell, you won't get much gain from exhaust mod except if you remove that secondary cat?

I gathered that, except for DPs that is. The change of the rear section(s) would be mostly for the acoustics/sound. I guess the question is to what degree it gets 'pleasantly loud' before getting to 'PITA loud' on the highway. Of course we will all have our individual preferences!!

A good quality clip would be great at this point.

[Gemballa1980]

I was looking at a bmw PE as well, as all others fall into the 'PITA' loud group for me; except maybe the Remus Sport, although I've only heard sounds clips of it. Then I got the 3" AR's (catless) and am more than happy with the note. Sounds good with windows down, and can hardly hear it when they're up. Since you're in Canberra, if you want a listen - hit me up!

Meanwhile, TNT just turned up at my door with a shiny new Helix FMIC and ER CP. Goes in tomorrow!

[blk335msport]

What's the going dealer rate for a BMW PE for the e92?

[DR-JEKL]

Originally Posted by blk335msport

What's the going dealer rate for a BMW PE for the e92?

I know I have been quoted $1300 delivered (2 weeks DHL from Germany)

[Zen]

Heres a clip I have made of my performance exhaust.

Sorry for the shitty video editing..

Enjoy!

[DR-JEKL]

Sounds great congratulations

[JJH]

I thought I would post this up just in case someone was ever interested.

I undetstand this is the factory exhaust from an E92 335i - downpipes back, lying upside down on the ground. I thought it surprising that the centre section in particular looks to be rather messy with sharp bends and crushed pipes (especially on the RHS, left in photo). I guess to package the system around the under floor area but maybe at the cost of gas flow?

[kaitan]

Originally Posted by Zen

Heres a clip I have made of my performance exhaust.

Sorry for the shitty video editing..

Enjoy!

Do you feel any power gain?