Aftermarket exhaust

[Dayalan]

Which aftermarket exhaust best suits the N42 and is it advisable to change from extractor or just the tail muffler is sufficient. Worried about issues that may arise from the upgrading of extractor

 

[Dayalan]

Would it trigger any OBD faults?

 

[subsonique]

i would definitely would love to go for either catback or the whole system, from the header/extractor/manifold right to the exhaust tip. most stock exhaust system are restrictive, even from the header itself. as for OBD faults, i think you will need a dongle for that.

 

[Devillian]

Just be wary for the headers... quite a few of them aren't designed properly for performance. They will give you a good sound but you would actually lose power.
Headers should only be upgraded when you vehicle goes past a certain threshold of air flow. If you consider supercharged engine running 7-10PSI boost still recommend the stock headers, it gives you a benchmark of how much more air you need to be flowing before the headers actually start to be useful.

 

[B33mEr]

Just be wary for the headers... quite a few of them aren't designed properly for performance. They will give you a good sound but you would actually lose power.
Headers should only be upgraded when you vehicle goes past a certain threshold of air flow. If you consider supercharged engine running 7-10PSI boost still recommend the stock headers, it gives you a benchmark of how much more air you need to be flowing before the headers actually start to be useful.

Not sure for FI but headers do makes a difference for NA. As you know M54 engine the cats is at the header near the exhaust port, that itself restrict the exhaust flow. Plenty of dyno sheets to prove that at e46fanatics.

 

[krsna86]

Not sure for FI but headers do makes a difference for NA. As you know M54 engine the cats is at the header near the exhaust port, that itself restrict the exhaust flow. Plenty of dyno sheets to prove that at e46fanatics.

Bro, would DeCat solve this restriction issue?

 

[B33mEr]

Bro, would DeCat solve this restriction issue?

If you mean taking out the cats at the manifold yes but then you have to remap to take out the check engine light and a tune to optimise the mods.

The correct approach would be getting the a proper exhaust manifold like these guys are making - http://www.motorsportsdownunder.com/catalog/i41.html They even make a turbo manifold :4:
But it is expensive since not many company is willing to make rhd manifold for the M54 ... whether you can justify the cost is up to you really.

P/s: i know one guy that installed headers from motorsports Downunder for his 523i M52 engine ... From what i can tell he loves it and there is no issue. Admittedly M54 is a more complex system specially with the DME.

 

[anaksarawak]

If you mean taking out the cats at the manifold yes but then you have to remap to take out the check engine light and a tune to optimise the mods.

The correct approach would be getting the a proper exhaust manifold like these guys are making - http://www.motorsportsdownunder.com/catalog/i41.html They even make a turbo manifold :4:
But it is expensive since not many company is willing to make rhd manifold for the M54 ... whether you can justify the cost is up to you really.

P/s: i know one guy that installed headers from motorsports Downunder for his 523i M52 engine ... From what i can tell he loves it and there is no issue. Admittedly M54 is a more complex system specially with the DME.

Bro nice sharing, any cat on N42/46 engine???

 

[aidilj]

Bro nice sharing, any cat on N42/46 engine???

Yes, delete it!

 

[Devillian]

Not sure for FI but headers do makes a difference for NA. As you know M54 engine the cats is at the header near the exhaust port, that itself restrict the exhaust flow. Plenty of dyno sheets to prove that at e46fanatics.

I agree cats are restrictive and that a well done header would still provide a gain. My warning was against any headers that haven't been designed with a proper R&D. A large portion of them will not provide a power gain and actually reduce the overall power and efficiency of the engine. The amount of work that actually goes into designing a proper header is a lot more tedious than most people think. It isn't like air intakes where "more flow is better". If you have too smooth a flow, at certain rpms some of the air/fuel mixture coming into the engine gets lost through the exhaust instead of staying in the cylinder.

 

[wingzee]

Since we're on the topic of headers and cats, would deleting the car actually affects the FC in any way?

 

[anaksarawak]

Yes, delete it!

WOW!! Delete it and code to clear the error code will help to gain more power? Wont the car be running rich and FC be very high?

 

[aidilj]

Since we're on the topic of headers and cats, would deleting the car actually affects the FC in any way?

I didn't experience any adverse effect with fuel consumption after deleting the cat

WOW!! Delete it and code to clear the error code will help to gain more power? Wont the car be running rich and FC be very high?

Surprisingly Bro, there was no error light or code with deletion of cat on my machine. The post cat sensor is the one which shouldve make sure its function is still good. Cat is to burn unburn fuel during combustion and convert contaminant to environmental friendly one before letting it go out of exhaust. Deleting the cat wont make your car run rich

 

[aidilj]

This is then how the exhaust failed on me, too much restriction by the muffler?

 

[Devillian]

This is then how the exhaust failed on me, too much restriction by the muffler?

That would have been sheared off from stress rather than from "air flow restriction". Was that section welded on or a one-piece cast?

 

[krsna86]

I didn't experience any adverse effect with fuel consumption after deleting the cat



Surprisingly Bro, there was no error light or code with deletion of cat on my machine. The post cat sensor is the one which shouldve make sure its function is still good. Cat is to burn unburn fuel during combustion and convert contaminant to environmental friendly one before letting it go out of exhaust. Deleting the cat wont make your car run rich

Bro, did you DeCat and put a bullet there or just sambung additional piping?

 

[aidilj]

That would have been sheared off from stress rather than from "air flow restriction". Was that section welded on or a one-piece cast?

Thanks for that Bro, at least I know that a low restriction muffler is not required. It seems to be welded and not one-piece cast. Also had the same failure at the resonator just after extractor not too long ago. The extractor also leaks in monthly basis

 

[anaksarawak]

I didn't experience any adverse effect with fuel consumption after deleting the cat



Surprisingly Bro, there was no error light or code with deletion of cat on my machine. The post cat sensor is the one which shouldve make sure its function is still good. Cat is to burn unburn fuel during combustion and convert contaminant to environmental friendly one before letting it go out of exhaust. Deleting the cat wont make your car run rich

Look like I will be busy this weekend to replace then chain tensioner and to remove the cat

 

[aidilj]

Bro, did you DeCat and put a bullet there or just sambung additional piping?

Bro' I've told them to throw that portion out and put a pipe, but due to the fact that O2 sensor bung is mounted on the cat portion they just operated the portion out and seal back.

By the way, N42 pre 2003 march and post 2003 march has different cat and O2 sensors configuration

 

[krsna86]

Bro' I've told them to throw that portion out and put a pipe, but due to the fact that O2 sensor bung is mounted on the cat portion they just operated the portion out and seal back.

By the way, N42 pre 2003 march and post 2003 march has different cat and O2 sensors configuration

Ahhh, sounds like a job for a professional exhaust shop. Anyway mine is M54 bro...same principle applies?