235 Muffler Delete *Your Thoughts*

bryan_G01 · 03-04-2016, 11:22 AM

sounds great. reminds me of the ftype.

Mywifes335 · 03-05-2016, 08:58 PM

OK, finally. Here are the details of the exhaust:

1. ER Catless DP
2. Removed stock resonator
3. Removed fiberglass packing from chamber 1 and 3 and perforated tube replaced with straight tubing
4. External bypass installed prior to muffler into the driver's side tip
5. 4" SS tips installed and welded
6. All tubing used is 409 stainless steel and MIG welded

Similar to Marv, I came to this "system" through first installing the ER catless DP then 3 trial and error exhaust modifications and fitments.

The first step was installing the ER DP, which added more sound at WOT and made the overrun more noticeable. No drone and barely louder than stock in the cabin.

The second step was installing the external bypass just ahead of the stock muffler into the driver's side tip. At the same time, the flapper valve was left open and the actuator was disconnected and tied off. No noticeable change in sound over the first step.

The third step was using a plasma cutter to open up the 1st and 3rd chambers of the stock exhaust and removing the fiberglass packing. Then the perf core in the 3rd chamber was replaced with straight pipe. The muffler was then welded back together. This mod made a noticeable difference in the overall sound while cruising - you can actually hear a hint of the straight 6 sound. At WOT the car was louder as well. The overrun became very pronounced, the cracks and pops sounded like muted gunshots. No drone. Idle was smooth and quiet after warm up (RPMs drop).

The last step was removing the resonator and replacing the section with a straight 409 stainless steel pipe. Then, 2 4" 304 stainless exhaust tips were welded on. The car got just a bit louder than before overall. However, the exhaust note during idle finally sounded more fitting for a sports car.

Result: very happy. I give credit to the guy who did this first in the F30 as well as dd1981. Also, Starvmarv for the inspiration. Finally, Denny and the guys at Mufflex in Trenton, NJ for all the patience and Fabwork. According to Mufflex, retail for this exact setup in 409 stainless would run somewhere in the mid-$600 range.

Pics:

Unable to upload video directly. Please advise (first time).

Mywifes335 · 03-05-2016, 09:12 PM

Video:

At idle, AFTER the cold start smoothed out.

Mywifes335 · 03-10-2016, 05:09 PM

Enjoy!

No drone, Actually sounds like an In-line 6. The overrun can get a bit obnoxious, but fun.

StarMan · 03-10-2016, 08:57 PM

Quote:

Originally Posted by Mywifes335

No drone, Actually sounds like an In-line 6. The overrun can get a bit obnoxious, but fun.

Sounds fantastic! Those tips look so much better. Fills in the gap quite well.

Mywifes335 · 03-10-2016, 09:29 PM

Thanks! Yours as well. You've been a great help!

AllEyesOnMe · 03-12-2016, 09:07 AM

Is it just the camera mic or does the car sound more raspy/tinny?

I wish it would sound more throatier.

I'm contemplating muffler delete mod as well.

Mywifes335 · 03-12-2016, 09:54 AM

Quote:

Originally Posted by AllEyesOnMe

Is it just the camera mic or does the car sound more raspy/tinny?

I wish it would sound more throatier.

I'm contemplating muffler delete mod as well.

Definitely throatier, more bass than stock.

Not raspy especially compared with an E60 M5 or E46 M3, there is none of that. Not sure turbo engines can actually get raspy like NA motors.

Taken on phone camera and compressed video.

AllEyesOnMe · 03-12-2016, 09:59 AM

Quote:

Originally Posted by Mywifes335

Definitely throatier, more bass than stock.

Not raspy especially compared with an E60 M5 or E46 M3, there is none of that. Not sure turbo engines can actually get raspy like NA motors.

Taken on phone camera and compressed video.

I watched other vids and it is indeed throatier!

I've the DP right now and inside cabin, it still sounds stock. How is it with the muffler delete?

I'm looking to go quad tips and just waiting for a decent looking, decently-priced rear diffuser to pop up... Crazy how F30 quad diffuseres are $250 while ours are $500!

Mywifes335 · 03-12-2016, 10:11 AM

Quote:

Originally Posted by AllEyesOnMe

I watched other vids and it is indeed throatier!

I've the DP right now and inside cabin, it still sounds stock. How is it with the muffler delete?

I'm looking to go quad tips and just waiting for a decent looking, decently-priced rear diffuser to pop up... Crazy how F30 quad diffuseres are $250 while ours are $500!

Man, I wanted quad tips so bad, it was just crazy how much they cost for generic ones! I even picked out these carbon fiber tips on Ebay for the setup.

I have ER catless downpipe. Inside the cabin it's louder but it's not bad and no drone.

As a reminder, my muffler is GUTTED. The chambers and box is still there. It's the packing that's removed and the perf cores are replaced with straight tubing inside. That's one way to avoid drone. If you just chop it off, it'll be even deeper but certain low frequencies (see marvs research in this thread) will drone badly. Stavmarv put in a Helmholtz chamber to help kill some frequencies.

The car has great sound deadening inside so while outside its pretty loud, the inside is livable. You don't need to shout to have a conversation or turn up the stereo to cruise.

Hope this helps!

AllEyesOnMe · 03-12-2016, 04:33 PM

Decisions, decisions!

I may go muffler delete first and see how livable the drone is first...

Marv, are you still experimenting with different-sized Helmholtz resonator or have you settled on the initial one?

StarMan · 03-12-2016, 06:27 PM

Quote:

Originally Posted by AllEyesOnMe

Decisions, decisions!

I may go muffler delete first and see how livable the drone is first...

Marv, are you still experimenting with different-sized Helmholtz resonator or have you settled on the initial one?

I haven't had time to mess with it some more. Plus I have other mods I need to install, I still need to install a charge pipe, and actually about to custom dyno tune the car in the upcoming weekends. I'll mess with the exhaust resonator after all of those expenses and more free time.

AK.Alexx · 03-14-2016, 03:08 AM

Very nice exhaust mod! A bit the same as BCS?

AK.Alexx · 03-17-2016, 08:51 AM

What does the fibergass do in the OEM backbox? Does it change the sound if you let it in or remove it? More drone?

Mywifes335 · 03-17-2016, 09:43 AM

Quote:

Originally Posted by Alexx911

What does the fibergass do in the OEM backbox? Does it change the sound if you let it in or remove it? More drone?

It makes it louder and more bass. No drone at all.

AK.Alexx · 03-17-2016, 09:54 AM

Quote:

Originally Posted by Mywifes335

It makes it louder and more bass. No drone at all.

Ok. Thanks! Maybe only delete the fibergass, or would you weld everything, if you have to open the backbox?

Mywifes335 · 03-17-2016, 10:39 AM

Quote:

Originally Posted by Alexx911

Ok. Thanks! Maybe only delete the fibergass, or would you weld everything, if you have to open the backbox?

You can use a plasma cutter to open up the backbox and peel the sheet metal back to expose each chamber. Then weld everything back.

AK.Alexx · 03-17-2016, 02:35 PM

Did someone put the fibergas in chamber 2? This saturday my exhaust specialist will do this mod. But I don't want a sharp sound.. I want a nice bang when upshift, etc..

Mywifes335 · 03-17-2016, 03:19 PM

It sounds very similar to the Armytrix exhaust on upshift. Like a fart.

AK.Alexx · 03-18-2016, 02:46 PM

Catless downpipe - stock midsilencer - oem backbox with bypass valve controlled.

Love the deep howl, really like the sound. But I want a more upshift sound and bang. So tomorrow backbox mod. Will the sound be more raspy or just louder? Thx!

Mywifes335 · 03-18-2016, 07:06 PM

Shouldn't be raspy. Doesn't sound raspy in person.

AK.Alexx · 03-23-2016, 08:14 AM

Quote:

Originally Posted by Mywifes335

Shouldn't be raspy. Doesn't sound raspy in person.

Is there a reason why you only modified chamber 3? Most people also weld chamber 1.

Anyone returned the fibergas in the second chamber? Or does it not have any effect?
Delete the fibergas or let it in, is there a big difference in sound or drone?

03-04-2016, 11:22 AM	#89
bryan_G01 Lieutenant Colonel 1165 Rep 1,931 Posts Drives: like i stole it... Join Date: Jun 2012 Location: NY iTrader: (0)	sounds great. reminds me of the ftype. __________________ www.nybmwcca.org Current Cars: 1995 M3 Coupe Manual Alpine White 1997 M3 Sedan Auto Cosmo Black Metallic 2018 x3 m40 Auto Grey Metallic
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03-10-2016, 09:29 PM	#94
Mywifes335 Major 1631 Rep 1,422 Posts Drives: 2014 FBO M235i Join Date: Oct 2010 Location: DFW iTrader: (1)	Thanks! Yours as well. You've been a great help!
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03-12-2016, 09:07 AM	#95
AllEyesOnMe TeQuiero 85 Rep 424 Posts Drives: BMW M2C Join Date: Jun 2008 Location: Orange County, CA iTrader: (4)	Is it just the camera mic or does the car sound more raspy/tinny? I wish it would sound more throatier. I'm contemplating muffler delete mod as well.
	Appreciate 0 Quote

03-12-2016, 04:33 PM	#99
AllEyesOnMe TeQuiero 85 Rep 424 Posts Drives: BMW M2C Join Date: Jun 2008 Location: Orange County, CA iTrader: (4)	Decisions, decisions! I may go muffler delete first and see how livable the drone is first... Marv, are you still experimenting with different-sized Helmholtz resonator or have you settled on the initial one?
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03-14-2016, 03:08 AM	#101
AK.Alexx Private First Class 50 Rep 111 Posts Drives: BMW M2 on order Join Date: Feb 2014 Location: BELGIUM iTrader: (0)	Very nice exhaust mod! A bit the same as BCS?
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03-17-2016, 08:51 AM	#102
AK.Alexx Private First Class 50 Rep 111 Posts Drives: BMW M2 on order Join Date: Feb 2014 Location: BELGIUM iTrader: (0)	What does the fibergass do in the OEM backbox? Does it change the sound if you let it in or remove it? More drone?
	Appreciate 0 Quote

03-17-2016, 02:35 PM	#106
AK.Alexx Private First Class 50 Rep 111 Posts Drives: BMW M2 on order Join Date: Feb 2014 Location: BELGIUM iTrader: (0)	Did someone put the fibergas in chamber 2? This saturday my exhaust specialist will do this mod. But I don't want a sharp sound.. I want a nice bang when upshift, etc..
	Appreciate 0 Quote

03-17-2016, 03:19 PM	#107
Mywifes335 Major 1631 Rep 1,422 Posts Drives: 2014 FBO M235i Join Date: Oct 2010 Location: DFW iTrader: (1)	It sounds very similar to the Armytrix exhaust on upshift. Like a fart.
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03-18-2016, 02:46 PM	#108
AK.Alexx Private First Class 50 Rep 111 Posts Drives: BMW M2 on order Join Date: Feb 2014 Location: BELGIUM iTrader: (0)	Catless downpipe - stock midsilencer - oem backbox with bypass valve controlled. Love the deep howl, really like the sound. But I want a more upshift sound and bang. So tomorrow backbox mod. Will the sound be more raspy or just louder? Thx!
	Appreciate 0 Quote

03-18-2016, 07:06 PM	#109
Mywifes335 Major 1631 Rep 1,422 Posts Drives: 2014 FBO M235i Join Date: Oct 2010 Location: DFW iTrader: (1)	Shouldn't be raspy. Doesn't sound raspy in person.
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