Modifying the exhaust system of my N53 engine

iGideon_523i · 11-01-2022, 03:36 PM

Hi forum members of the E90 post!

I'm all new to the forum, so hi to all!

Let me introduce myself; I'm Gideon from The Netherlands and proud owner of a beautiful white 330i N52 and a black 523i N53, I work for a mechanic shop, and live on my own for a little while now.

Since may this year, I;ve gotten myself another extra daily commuter, in this case an older 523i, my 330i is currently mainly sitting in the garage as a keeper, planning on storing it for a while since driving 2 cars is a little overdone (insane tax, and gas prices)

The question in this case is more E60 related, it's an Lci by the way.

The thing is as follows;
- My 523i is completely stock, running the rather boring N53B25 engine, the smaller, more efficient variant of the N53 engine family.
I currently have the issue that it runs a little sluggish, mainly NOX system related since my injectors are new, coil packs and plugs have been done also, all gaskets etc have been taken care of, new valve cover, all the stuff is OEM BMW.
The only issue it has? EGR and NOX issues.

What is my plan?
- Getting rid of the NOX system in general, and I am planning on doing it the following way.
Replace the full exhaust system, I currently have 2 primary cats on the headers, and 2 NOX secondary cars, those NOX cats are part of the exhaust system, and are bolted on to the headers.
I've gotten my hands on a brand new, genuine BMW E60 exhaust system, made for the N52 engines.
The new exhaust system doesn't have the cats, NOX sensor thread, nothing emission related.
I am wondering if someone successfully deleted the Nox system, and also mapped out the EGR, and what are the results? I will keep the primary cats for MOT inspection.
I also remove the NOX sensor in general, or must it be in the exhaust flow? I can always weld a thread into the pipe for the sensor if needed.

Thanks in advance, I'm really curious and there isn't a lot of info on this engine regarding the NOX system.

I also want to turn off the EGR valve if possible, it only clogs up the intake ports, I've just walnut blasted them so I prefer keeping them clean.

11-01-2022, 03:36 PM	#1
iGideon_523i Registered 0 Rep 1 Posts Drives: BMW 523i N53 - 2007 Join Date: Nov 2022 Location: The Netherlands iTrader: (0)	Modifying the exhaust system of my N53 engine Hi forum members of the E90 post! I'm all new to the forum, so hi to all! Let me introduce myself; I'm Gideon from The Netherlands and proud owner of a beautiful white 330i N52 and a black 523i N53, I work for a mechanic shop, and live on my own for a little while now. Since may this year, I;ve gotten myself another extra daily commuter, in this case an older 523i, my 330i is currently mainly sitting in the garage as a keeper, planning on storing it for a while since driving 2 cars is a little overdone (insane tax, and gas prices) The question in this case is more E60 related, it's an Lci by the way. The thing is as follows; - My 523i is completely stock, running the rather boring N53B25 engine, the smaller, more efficient variant of the N53 engine family. I currently have the issue that it runs a little sluggish, mainly NOX system related since my injectors are new, coil packs and plugs have been done also, all gaskets etc have been taken care of, new valve cover, all the stuff is OEM BMW. The only issue it has? EGR and NOX issues. What is my plan? - Getting rid of the NOX system in general, and I am planning on doing it the following way. Replace the full exhaust system, I currently have 2 primary cats on the headers, and 2 NOX secondary cars, those NOX cats are part of the exhaust system, and are bolted on to the headers. I've gotten my hands on a brand new, genuine BMW E60 exhaust system, made for the N52 engines. The new exhaust system doesn't have the cats, NOX sensor thread, nothing emission related. I am wondering if someone successfully deleted the Nox system, and also mapped out the EGR, and what are the results? I will keep the primary cats for MOT inspection. I also remove the NOX sensor in general, or must it be in the exhaust flow? I can always weld a thread into the pipe for the sensor if needed. Thanks in advance, I'm really curious and there isn't a lot of info on this engine regarding the NOX system. I also want to turn off the EGR valve if possible, it only clogs up the intake ports, I've just walnut blasted them so I prefer keeping them clean.
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