[F36 435i M]

Hi guys,

Please forgive me if this has been asked many times before but I haven’t found a single post regarding this on the 435i. I currently have a resonator delete and although the car does sound good, i wouldn’t mind a bit more volume. I’ve been recommended by a friend to get the muffler removed next however, will this cause too much drone as I already have the resonator removed? (I currently have no drone) if someone has done this on the 435i on here, your response would be amazing. I don’t want to get it done and then be shocked at how loud the drone is and if there is only a small amount I am happy to go through with it.

A downpipe isn't something I want to do due to it not passing MOT and a catback or MPE is just a bit too expensive for me right now.

Thank you in advance

[thejeremyman9]

Not sure how strict your visual inspection is for MOT, but there are downpipes that will get your emissions monitor ready so will pass the OBD2 check. In theory they could still fail visual, that's something you would need to confirm.

Muffler and resonator delete basically means straight pipe after the DP. OEM DP mutes sound a little but it is unavoidably going to drone. It's going to come down to your level of tolerance/preference as is the case with any exhaust setup.

You can also consider something like this: https://f30.bimmerpost.com/forums/sh...d.php?t=819125

Also, i just did a google search for "n55 bmw muffler and resonator delete" and got tons of hits...

[F36 435i M]

Originally Posted by thejeremyman9

Not sure how strict your visual inspection is for MOT, but there are downpipes that will get your emissions monitor ready so will pass the OBD2 check. In theory they could still fail visual, that's something you would need to confirm.

Muffler and resonator delete basically means straight pipe after the DP. OEM DP mutes sound a little but it is unavoidably going to drone. It's going to come down to your level of tolerance/preference as is the case with any exhaust setup.

You can also consider something like this: https://f30.bimmerpost.com/forums/sh...d.php?t=819125

Also, i just did a google search for "n55 bmw muffler and resonator delete" and got tons of hits...

Thanks for the reply.

Do you mind linking the downpipe you mentioned? I can then contact my MOT centre and see if they can pass it through.

The posts that are on google don't really explain or show the drone with both the res and muffler delete. The posts I have found which briefly describes it either say the drone is terrible, or there is barely any. So I have no idea what to believe haha.

I just want to know if driving in comfort and eco gives the car minor drone on the motorway or if it's quite noticeable.

[thejeremyman9]

AA is probably the "most legal" one: https://store.activeautowerke.com/pr...atted-downpipe

Fabspeed and CG precision can also pass OBD2 checks.

The reason why you get different information is because everyone's tolerance for drone and exhaust preference is different. Straight pipe is going to be loud and drone, the question is just if its something you want to live with.

[F36 435i M]

Originally Posted by thejeremyman9

AA is probably the "most legal" one: https://store.activeautowerke.com/pr...atted-downpipe

Fabspeed and CG precision can also pass OBD2 checks.

The reason why you get different information is because everyone's tolerance for drone and exhaust preference is different. Straight pipe is going to be loud and drone, the question is just if its something you want to live with.

Yes it's annoying as it does look like some may be complaining when it actually isn't too bad. Do you know if a catted downpipe would be worth doing? It will easily pass MOT and sources say its only slightly less louder than a full decat downpipe.

[thejeremyman9]

Originally Posted by F36 435i M

Yes it's annoying as it does look like some may be complaining when it actually isn't too bad. Do you know if a catted downpipe would be worth doing? It will easily pass MOT and sources say its only slightly less louder than a full decat downpipe.

Catted DP is better than any exhaust mod because it actually provides a performance increase... not to mention the sound change. The difference in sounds between catted and catless depends on your midpipe/muffler setup. The stock muffler is pretty tame which is why there is not a huge difference between the two. The difference will be greater with a muffler that is louder in the first place.

If your MOT requires your catalyst emission monitor to be ready then you need to make sure you get a DP like AA that will do so; the cheap catted DPs will not, and will throw a CEL.

I run fabspeed catted DP with resonator delete, stock axleback muffler. It's the right amount of sounds for me but i did not want this car to be excessively loud and wanted zero drone.

Note that the car always sounds louder (and typically better) from behind so camera angle is a big factor in how it sounds, and the rear of the car sounds much different than in cabin.

[F36 435i M]

Originally Posted by thejeremyman9

Catted DP is better than any exhaust mod because it actually provides a performance increase... not to mention the sound change. The difference in sounds between catted and catless depends on your midpipe/muffler setup. The stock muffler is pretty tame which is why there is not a huge difference between the two. The difference will be greater with a muffler that is louder in the first place.

If your MOT requires your catalyst emission monitor to be ready then you need to make sure you get a DP like AA that will do so; the cheap catted DPs will not, and will throw a CEL.

I run fabspeed catted DP with resonator delete, stock axleback muffler. It's the right amount of sounds for me but i did not want this car to be excessively loud and wanted zero drone.

Note that the car always sounds louder (and typically better) from behind so camera angle is a big factor in how it sounds, and the rear of the car sounds much different than in cabin.

That sounds really damn good, think you've sold me on getting a catted downpipe. So if I installed one on mine, as long as they aren't a cheap one, the sound improvement would be similar to yours? (I have a res delete already). If so I just need to hunt for one then as I live in the UK and the site I looked at was the one linked below, they did say it would throw a CEL which I am not too happy about like you said:

https://cobrasport.com/products/bmw-...wnpipe-exhaust

Will need to look around more for others

[thejeremyman9]

Originally Posted by F36 435i M

That sounds really damn good, think you've sold me on getting a catted downpipe. So if I installed one on mine, as long as they aren't a cheap one, the sound improvement would be similar to yours? (I have a res delete already). If so I just need to hunt for one then as I live in the UK and the site I looked at was the one linked below, they did say it would throw a CEL which I am not too happy about like you said:

https://cobrasport.com/products/bmw-...wnpipe-exhaust

Will need to look around more for others

Yes, all catted DP will sound similar to one another, although the cat "density" (aka cells) will slightly change how loud it is. Again just remember that clip basically shows how it sounds outside the car (i.e., to other people), its still pretty quiet in the cabin, but you do get way more turbo noise/spool than stock and of course more volume. The other key thing is that a DP actually adds power.

Your best bet is to check for someone who has specifically passed MOT in your area with a catted DP and which they used.

[F36 435i M]

Originally Posted by thejeremyman9

Yes, all catted DP will sound similar to one another, although the cat "density" (aka cells) will slightly change how loud it is. Again just remember that clip basically shows how it sounds outside the car (i.e., to other people), its still pretty quiet in the cabin, but you do get way more turbo noise/spool than stock and of course more volume. The other key thing is that a DP actually adds power.

Your best bet is to check for someone who has specifically passed MOT in your area with a catted DP and which they used.

Surely it will pass okay? As the cat is still there? And sorry just one last question, I have heard gutting the stock muffler would work? That was I keep the valve system but also get the noise when I want it? This would be a much cheaper option for me as a downpipe is going to cost £600+ and then the labour and I could always do that once i have more money to spend haha

[thejeremyman9]

Originally Posted by F36 435i M

Surely it will pass okay? As the cat is still there? And sorry just one last question, I have heard gutting the stock muffler would work? That was I keep the valve system but also get the noise when I want it? This would be a much cheaper option for me as a downpipe is going to cost £600+ and then the labour and I could always do that once i have more money to spend haha

No. Not all catted DPs pass emissions. The cheaper ones are not efficient/effective enough and will throw a CEL and/or will not get your emission monitor "READY", so when they do a OBD2 scan, they will see something is off.

I already linked above about modifying stock muffler... https://f30.bimmerpost.com/forums/sh...d.php?t=819125

[Eli7]

I did a resonator and muffler delete on my 435 and it honestly sounds pretty good for how much it costed. Given, it does drone a bit at certain rpm but it's no where near as bad as I had thought. I did keep the stock exhaust flaps so it's a bit more muted when it's in comfort or eco mode. The car has a much throatier sound and tends to have more pronounced pops even when stock.

I didn't want to do a DP since it's a PITA in my state when it comes to emissions and inspections. I know a friend who has a catless DP which makes the pops much more louder than mine. However, it's been a hassle for him trying to pass the yearly inspections here.

[thejeremyman9]

Originally Posted by Eli7

I did a resonator and muffler delete on my 435 and it honestly sounds pretty good for how much it costed. Given, it does drone a bit at certain rpm but it's no where near as bad as I had thought. I did keep the stock exhaust flaps so it's a bit more muted when it's in comfort or eco mode. The car has a much throatier sound and tends to have more pronounced pops even when stock.

I didn't want to do a DP since it's a PITA in my state when it comes to emissions and inspections. I know a friend who has a catless DP which makes the pops much more louder than mine. However, it's been a hassle for him trying to pass the yearly inspections here.

There are DPs that pass emissions.

[TerryGTX]

Originally Posted by Eli7

I did a resonator and muffler delete on my 435 and it honestly sounds pretty good for how much it costed. Given, it does drone a bit at certain rpm but it's no where near as bad as I had thought. I did keep the stock exhaust flaps so it's a bit more muted when it's in comfort or eco mode. The car has a much throatier sound and tends to have more pronounced pops even when stock.

I didn't want to do a DP since it's a PITA in my state when it comes to emissions and inspections. I know a friend who has a catless DP which makes the pops much more louder than mine. However, it's been a hassle for him trying to pass the yearly inspections here.

Wondering what's gonna happen with your DP after the PS1

Will see ..