[Ripley]

Originally Posted by Glowin

And no drone??? Whitefury swears that you'll get drone if you remove all the packing, which sort of makes sense I have to admit. But I guess the packing is probably most important around the pipes that remain perforated...

I removed only all the packing around straight pipes (like performance exhaust).

Muffler y-pipe sides weren't opened, so packing material is still all there.

I have to ride on the highway to check the drone.

[blaster3500]

Originally Posted by Ripley

I removed only all the packing around straight pipes (like performance exhaust).

Muffler y-pipe sides weren't opened, so packing material is still all there.

I have to ride on the highway to check the drone.

Do you have stock downpipes?

[westchester335i]

I removed all the packing and covered every pipe in both mufflers with exhaust wrap. There is definitely drone on the highway and driving around hills locally, it can be loud but its not that annoying. Another reason why I may have drone is because my resonator is deleted and has been replaced with a magnaflow x pipe.

[Ripley]

Originally Posted by blaster3500

Do you have stock downpipes?

No, I have VRSF 3 dps

[WhiteFury]

Originally Posted by westchester335i

I removed all the packing and covered every pipe in both mufflers with exhaust wrap. There is definitely drone on the highway and driving around hills locally, it can be loud but its not that annoying. Another reason why I may have drone is because my resonator is deleted and has been replaced with a magnaflow x pipe.

Resonators dont dictate drone unless you have no cats, or mufflers. If you do not have packing in your muffler its basically a straight pipe.

I have no resonators, and my own modded muffler and it makes literally ZERO noise on the highway.

You have to understand the physics of sound, how it moves, and what happens. Why do you think mufflers get hot? Yes gases are hot but when sound travels and gets stopped by rockwool or absorbing material, it generates heat. Energy has to go somewhere.

Removing packing doesn mean your exhaust will be louder per say, it will have more drone. If you want it louder, follow my advise and leave the Y pipes packed, and get a catless down pipe.

[Ripley]

I'm starting to think that it is almost impossible to compare the sound of the exhaust with a simple video, but I'll try anyway to make one this week.

I do not have specific equipment to make videos with the car in motion. Any advice?

I was thinking of gluing the iPhone to the plate holder with double sided tape but it does not seem like a brilliant idea...

[westchester335i]

When I had my mufflers stock and the resonator deleted my car did drone.

I am getting catless downpipes soon, it will be 100% with that. For right now it sounds great. I bought a gopro3 the other day, let me try to get a good video when it comes in.

[StevenY.]

Originally Posted by Ripley

I'm starting to think that it is almost impossible to compare the sound of the exhaust with a simple video, but I'll try anyway to make one this week.

I do not have specific equipment to make videos with the car in motion. Any advice?

I was thinking of gluing the iPhone to the plate holder with double sided tape but it does not seem like a brilliant idea...

Maybe just throw your iPhone in the trunk under that compartment where you can put a donut.

[Stock-ish]

Originally Posted by Ripley

I'm starting to think that it is almost impossible to compare the sound of the exhaust with a simple video, but I'll try anyway to make one this week.

I do not have specific equipment to make videos with the car in motion. Any advice?

I was thinking of gluing the iPhone to the plate holder with double sided tape but it does not seem like a brilliant idea...

To record with an iPhone, just use your headset taped to the bumper and stash the phone in the trunk so there's no risk. Not the best sound quality, but decent.

[Ripley]

Thanks, I'll try

[Josh1a1h]

I have been following this for ages!!!! HUGE THANKS to those who have chopped up thier PEs for us!

So what is the verdict??? what packing should be removed, what perforated piping should be wrapped or replaced?
In order to achieve a louder tone Without Any Drone...
I do not mind drone when the Exhaust flap is open, but the exhaust must not drone when the flap is closed.

Surely there should be a method that works?

[Ripley]

Well, last night I tried the car on the highway and did not hear the drone.
The car literally screams at high rpm, and it is quiet at low rpm.

Notes: To be honest, I was pretty drunk last night and I let drive my girl, but I think I've been paying attention to the noise while we were on the highway

Disconnecting the cable in the left compartment of tail light left, so holding the valve always open (golf tee mod), you get a lot of drone at constant speed on the highway. This happened even with just the VRSF downpipes and without modification to the muffler.

With the windows closed you maintain a good level of acoustic comfort, thanks also to good soundproofing of our BMW.

I am very happy of the results of this change, but knowing no one in my town with a N54 and a Performance Exhaust, I can not make objective comparisons.

I'm going to do some video by evening, that I will post tomorrow.

[blaster3500]

Can't wait to see your video should sound just like PE

[WhiteFury]

Originally Posted by Ripley

Well, last night I tried the car on the highway and did not hear the drone.
The car literally screams at high rpm, and it is quiet at low rpm.

Notes: To be honest, I was pretty drunk last night and I let drive my girl, but I think I've been paying attention to the noise while we were on the highway

Disconnecting the cable in the left compartment of tail light left, so holding the valve always open (golf tee mod), you get a lot of drone at constant speed on the highway. This happened even with just the VRSF downpipes and without modification to the muffler.

With the windows closed you maintain a good level of acoustic comfort, thanks also to good soundproofing of our BMW.

I am very happy of the results of this change, but knowing no one in my town with a N54 and a Performance Exhaust, I can not make objective comparisons.

I'm going to do some video by evening, that I will post tomorrow.

The valve on the driver side when closed forces the gas exhaust through the Y pipes connector and through the passenger side. Since the passenger side exhaust is perforated and the driver side is not, thats the reason a factory 335i is louder with the golf tee mod, only 50% of the exhaust travels through the passenger muffler. The rest goes through the resonator in the driver muffler.

If you remove all the packing in the Y connectors and/or cover the perforated pipe in the Y connectors as well as the passenger side you WILL get drone.

Even if you leave the packing on the passenger side but dump the packing in the Y pipe you WILL get drone.

I have the mufflers modded both driver and passenger side perforated pipes replaced. I have my packing still in the passenger and driver side to absorbed unwanted frequencies. I have left my Y connectors packed and perforated pipe alone.

I have said many times about sound, you have to understand it. I have zero drone. NONE. My exhaust is also just as loud as a PE.

If you mod a factory muffler and weld straight pipes in place of the perforated pipe on both sides, why take the packing out? It doesn't anything, and it wont make your exhaust quiet as the pipes are sealed straight through solid pipe.


To all members considering this mod, leave the Y pipes perforated and leave all the packing in those little spots. Just weld straight pipe on the passenger and driver side. PUT THE PACKING IN!

No's

1. no weight
2. doesnt make exhaust quiet (solid straight through pipes)
3. doesnt cost anything as it was there to begin with
4. you cant sell it to make money


YES's of the packing:

1. its free
2. it was already there
3. it prevents drone and high frequencies that are called harmonics on the exhaust pipe


Following this method results in no drone, and when the flap is closed it forces the driver side exhaust through 2 perforated and packed Y pipes and then through the straight pipe in the passenger side. Which in turn slows down the exhaust flow slightly. as it all fights to get out. Its a negative pressure builder like a silencer sort of, except plugging exhaust tips, you direct more gas into one spot. This = quieter exhaust.

So my method will give you the following:

1. stock like sound with flap closed (slightly louder)
2. no drone in cabin ZERO
3. gurgles, pops and amazing performance like the PE
4. no unwanted harmonics, and very quiet idle

I now have 2 mufflers consistent and they both sound identical as labeled above.

[Ripley]

I tried to make a video with the iphone 4s, but the sound quality is not the best (perhaps the smartphone is too close to the exhaust).

I'll try a second time with the samsung galaxy S4 because I do not have any audio professional equipment.

I'll do some in motion video later, if I can.

[Ripley]

Originally Posted by WhiteFury

The valve on the driver side when closed forces the gas exhaust through the Y pipes connector and through the passenger side. Since the passenger side exhaust is perforated and the driver side is not, thats the reason a factory 335i is louder with the golf tee mod, only 50% of the exhaust travels through the passenger muffler. The rest goes through the resonator in the driver muffler.

If you remove all the packing in the Y connectors and/or cover the perforated pipe in the Y connectors as well as the passenger side you WILL get drone.

Even if you leave the packing on the passenger side but dump the packing in the Y pipe you WILL get drone.

I have the mufflers modded both driver and passenger side perforated pipes replaced. I have my packing still in the passenger and driver side to absorbed unwanted frequencies. I have left my Y connectors packed and perforated pipe alone.

I have said many times about sound, you have to understand it. I have zero drone. NONE. My exhaust is also just as loud as a PE.

If you mod a factory muffler and weld straight pipes in place of the perforated pipe on both sides, why take the packing out? It doesn't anything, and it wont make your exhaust quiet as the pipes are sealed straight through solid pipe.


To all members considering this mod, leave the Y pipes perforated and leave all the packing in those little spots. Just weld straight pipe on the passenger and driver side. PUT THE PACKING IN!

No's

1. no weight
2. doesnt make exhaust quiet (solid straight through pipes)
3. doesnt cost anything as it was there to begin with
4. you cant sell it to make money


YES's of the packing:

1. its free
2. it was already there
3. it prevents drone and high frequencies that are called harmonics on the exhaust pipe


Following this method results in no drone, and when the flap is closed it forces the driver side exhaust through 2 perforated and packed Y pipes and then through the straight pipe in the passenger side. Which in turn slows down the exhaust flow slightly. as it all fights to get out. Its a negative pressure builder like a silencer sort of, except plugging exhaust tips, you direct more gas into one spot. This = quieter exhaust.

So my method will give you the following:

1. stock like sound with flap closed (slightly louder)
2. no drone in cabin ZERO
3. gurgles, pops and amazing performance like the PE
4. no unwanted harmonics, and very quiet idle

I now have 2 mufflers consistent and they both sound identical as labeled above.

Essentially I followed your method, perforated pipes replaced by straight pipes and y-pipes with sound-absorbing material around .

Basically I did not open the containers of y-pipes, leaving them exactly how BMW has made ​.

I also completely removed the sound-absorbing material around the straight pipes, exactly as seen in the photo of the passenger side Performance Exhaust opened.

Of course, I have no idea how the Performance Exhaust is done on the driver's side because no one has yet opened, but I assumed that it is equal to the passenger side (straight pipe), no resonator and no sound-absorbing material around.

I decided to do so for the following reasons :

1 . I'm still experimenting, and the presence of catless downpipes increases the sound of the exhaust of a lot, so I try to be cautious to avoid me to be stopped by the police every 10 minutes.

2 . I felt it was unnecessary to put the sound-absorbing material around the pipe straight.


With exhaust flap closed, I have no drone and my car gurgles and pops very nice

I repeat, my method is the same as yours except for the greater amount of sound-absorbing material (like OEM) around the y-pipes.

[secretsquirrel]

Originally Posted by WhiteFury

Resonators dont dictate drone unless you have no cats, or mufflers. If you do not have packing in your muffler its basically a straight pipe.

I have no resonators, and my own modded muffler and it makes literally ZERO noise on the highway.

You have to understand the physics of sound, how it moves, and what happens. Why do you think mufflers get hot? Yes gases are hot but when sound travels and gets stopped by rockwool or absorbing material, it generates heat. Energy has to go somewhere.

Removing packing doesn mean your exhaust will be louder per say, it will have more drone. If you want it louder, follow my advise and leave the Y pipes packed, and get a catless down pipe.

So... can we get a sound clip?

[Josh1a1h]

Originally Posted by WhiteFury

The valve on the driver side when closed forces the gas exhaust through the Y pipes connector and through the passenger side. Since the passenger side exhaust is perforated and the driver side is not, thats the reason a factory 335i is louder with the golf tee mod, only 50% of the exhaust travels through the passenger muffler. The rest goes through the resonator in the driver muffler.

If you remove all the packing in the Y connectors and/or cover the perforated pipe in the Y connectors as well as the passenger side you WILL get drone.

Even if you leave the packing on the passenger side but dump the packing in the Y pipe you WILL get drone.

I have the mufflers modded both driver and passenger side perforated pipes replaced. I have my packing still in the passenger and driver side to absorbed unwanted frequencies. I have left my Y connectors packed and perforated pipe alone.

I have said many times about sound, you have to understand it. I have zero drone. NONE. My exhaust is also just as loud as a PE.

If you mod a factory muffler and weld straight pipes in place of the perforated pipe on both sides, why take the packing out? It doesn't anything, and it wont make your exhaust quiet as the pipes are sealed straight through solid pipe.


To all members considering this mod, leave the Y pipes perforated and leave all the packing in those little spots. Just weld straight pipe on the passenger and driver side. PUT THE PACKING IN!

No's

1. no weight
2. doesnt make exhaust quiet (solid straight through pipes)
3. doesnt cost anything as it was there to begin with
4. you cant sell it to make money


YES's of the packing:

1. its free
2. it was already there
3. it prevents drone and high frequencies that are called harmonics on the exhaust pipe


Following this method results in no drone, and when the flap is closed it forces the driver side exhaust through 2 perforated and packed Y pipes and then through the straight pipe in the passenger side. Which in turn slows down the exhaust flow slightly. as it all fights to get out. Its a negative pressure builder like a silencer sort of, except plugging exhaust tips, you direct more gas into one spot. This = quieter exhaust.

So my method will give you the following:

1. stock like sound with flap closed (slightly louder)
2. no drone in cabin ZERO
3. gurgles, pops and amazing performance like the PE
4. no unwanted harmonics, and very quiet idle

I now have 2 mufflers consistent and they both sound identical as labeled above.

This is extremely helpful and it makes sense. it sounds like the right way of adding sound whilst keeping drone at bay.

I am going to get a quote for this tomorrow...

But one question...

Would i have to cut out the existing pipes and weld new ones in... Or Could i just use exhaust tape to strap up the perforated piping?

THanks for taking your time to explain

[Ripley]

Another video (warm engine)

[Glowin]

@Whitefury: So you're suggesting to just leave the pass and driver's side Y pipe sections alone, include their packing. So no need to open them up even then, right?

Just open up the outer half of each muffler to replace the canister (on driver's side) and the perf pipe (pass side) with straight pipes.

As an aside, a couple of questions for you:

1 - How much of our goal would be achieved if you just replaced the perf pipe on the pass side with a straight pipe, and you left the canister in the driver's side as is?

2 - When doing the above, Instead of replacing with a pipe, what if you just wrapped the perf section? Would that work too?

PS When your guy welds in the straight section, how does he manage to weld all the way around the pipe if he's just opened the top of the muffler?

[Glowin]

Originally Posted by WhiteFury

The valve on the driver side when closed forces the gas exhaust through the Y pipes connector and through the passenger side. Since the passenger side exhaust is perforated and the driver side is not, thats the reason a factory 335i is louder with the golf tee mod, only 50% of the exhaust travels through the passenger muffler. The rest goes through the resonator in the driver muffler.

One further comment on just the point above. On cold starts, the flap on the driver's side is closed, which forces the gas thru the passenger side, which must be the quieter of the two mufflers. The reason is that when you do the golf tee mod, and the driver's side is always open, it's louder.

Which then tells me that when gases are going thru the driver's side resonator, that increases the overall sound. Maybe it's because even though the outside pipe is perforated, it's still fully enclosed in the resonator enclosure, so it's sort of like a straight pipe to a degree? So why mess with it at all?

I am inclined to just mod the passenger side instead, now that I think about it, with the logic above.

[pocoyo_3]

I'm inclined to agree with Glowin's comments (and Whitefury's too). The drivers side muffler appears to be the louder of the two, and this is why the flap on the drivers side closes. The aim is to use the right hand side (quieter) muffler for low speeds and then open up both exhausts for high speeds.

My suspicion is that the drivers side is not so good at attenuating the sound from low RPMs and hence it is bypassed at low RPMs. I have PPK1 (which basically gives you the golf tee mod), and my car is noticeably growlier at low speeds.

If you don't have the golf tee mod, you can open up the drivers side and the car should be louder at higher RPMs but still quiet at low speeds. If you have the golf tee then modifying the drivers side will affect all engine speeds.