N52 130i/125i exhaust mod DIY (with 135i and resonator pics/info too)

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cplman79
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Re: 130i Exhaust Mod DIY (w/135i pics too)

Post by cplman79 »

Anyone based in Surrey that can help with this? Local garages not interested in this type of job and exhaust shops aren’t cheap ...
E87 130i M Sport
Nyxeris
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Re: 130i Exhaust Mod DIY (w/135i pics too)

Post by Nyxeris »

N52, N54/N55 & N54T Resonators

The N55's resonator has a lot less perforation than the N52. But it's worth bearing in mind that a resonator isn't a simple muffler/silencer, they're usually designed to kill a very specific (resonant) frequency - i.e. to stop drone. If the N55 and N52 resonators are designed to kill different frequencies then swapping them could sound ace, could sound identical to deleting it entirely, or it could do nothing at all!

Here's the internals of an N52 res (packing has already been removed):

Image

Here's the N54/N55 res from inside:

Image

FYI from what I understand the N54 & N55 resonators are identical, the difference is the N55 having no secondary cats and a less open backbox hence the better sound. This doesn't apply to the 1M/N54T as its resonator is fake - there's just has a Y pipe in there (same as the N54/N55 BMWP midpipe):

Image

Note: Posted this as a response on another thread a while ago, duplicating here for info. I've also reorganised the thread to make it a bit more readable so apologies if anyone's been spammed with notifications!
E81 130i | Thread
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awhc
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Re: N52 130i/125i exhaust mod DIY (with 135i and resonator pics/info too)

Post by awhc »

Has anyone got a borescope to look inside a 130i PE?

The wrapped pipe 1 doesn't really sound like a 130i PE.
Nyxeris
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Re: N52 130i/125i exhaust mod DIY (with 135i and resonator pics/info too)

Post by Nyxeris »

awhc wrote: Sat Jul 17, 2021 11:01 am Has anyone got a borescope to look inside a 130i PE?

The wrapped pipe 1 doesn't really sound like a 130i PE.
No, but this Bimmerpost thread might help. The N52 330i PE is a completely different internal design - it's basically a perforated Y-pipe straight to the tips rather than the spaghetti of tubes and bends you get in the standard one. If the 130i PE is internally similar it'd take major surgery to the standard backbox to imitate it.

This is also probably why the N55 exhaust sounds so good out of the box. It's just an internal Y pipe with some perforation in the middle... Exactly the same as that 330i PE.
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awhc
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Re: N52 130i/125i exhaust mod DIY (with 135i and resonator pics/info too)

Post by awhc »

Nyxeris wrote: Wed Jul 21, 2021 10:54 am
awhc wrote: Sat Jul 17, 2021 11:01 am Has anyone got a borescope to look inside a 130i PE?

The wrapped pipe 1 doesn't really sound like a 130i PE.
No, but this Bimmerpost thread might help. The N52 330i PE is a completely different internal design - it's basically a perforated Y-pipe straight to the tips rather than the spaghetti of tubes and bends you get in the standard one. If the 130i PE is internally similar it'd take major surgery to the standard backbox to imitate it.

This is also probably why the N55 exhaust sounds so good out of the box. It's just an internal Y pipe with some perforation in the middle... Exactly the same as that 330i PE.
Thanks! This is helpful.
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