So I started a thread about custom Magnaflow mufflers...

MikeE92M3 · 10-05-2012, 04:54 PM

And this will be the finish. Got everything installed today on my day off. As some of you may remember, I had installed the Magnaflow 14816 Mufflers and while I loved how it sounded, the drone was a bit much. My solution consisted of ordering a Magnaflow True X pipe, Aero AR25 Resonators, and OBX generic resonators. Why? I was going full custom. I already had my secondary cats taken off and replaced with straight pipes for those who had seen my post a few months back. To solve the drone issue, I used the helmholtz formula to create helmholtz chambers to cancel out the drone frequencies. This is what the OBX universal 2.5" resonators were for. For those who don't know, the OEM x pipe is crap--there is just a small "hole" where the exhaust gasses are supposed to crossover. Compared to the new magnaflow X pipe, this one was wide open. I already knew there were gonna be some positives with the new X pipe once I compared the two. The resonators replaced the OEM ones just past the x pipe. They fit perfectly. I had my tech create new pipes from the resonators back to the mufflers. Very straight through design with very few bends. He tried to make both of them perfect, and I think he did. The helmholtz chambers were created just as they are meant to perform, I needed roughly 13 inches to cancel out the frequencies, and they are placed where they belonged. I used the AA exhaust as a reference for the location where the pipes were to come off a 90 degree angle. 3 hours later, my new exhaust was done. The result? Absolutely little to no rasp, ZERO drone, and Immediate notice of more "pick up" with the new x pipe. He polished up the welds, especially on the helmholtz chambers, and they look fantastic. Really aggressive from behind. I absolutely love it and it is the most perfect thing I have heard besides women's sexual moans. Let's not go there. Of course, I will provide pictures and stand by for a sound clip either tomorrow or Sunday. I spent about $800 overall on EVERYTHING, including labor and parts. Couldn't be happier.

Pics:

ZRODDICK · 10-05-2012, 07:38 PM

Great job! Could you come up with a vadio?

BMRLVR · 10-05-2012, 08:14 PM

Happy you like it!

e46kyle · 10-07-2012, 01:08 PM

would love to hear how this sounds

MikeE92M3 · 10-07-2012, 11:36 PM

Quote:

Originally Posted by BMRLVR

Happy you like it!

I love it! Thanks

MikeE92M3 · 10-07-2012, 11:38 PM

Quote:

Originally Posted by e46kyle

would love to hear how this sounds

Will make a video soon. Had a wedding to go to this past weekend so I didn't have time. It sounds AWESOME. It sounds like a wicked/pissed off combination of an exotic/almost muscle like, but this is how the V8 comes to life!

MikeE92M3 · 10-07-2012, 11:41 PM

Now I just need to get a rear diffuser to tie it all in.

dmk08 · 10-11-2012, 09:50 AM

Quote:

Originally Posted by MikeE92M3

Now I just need to get a rear diffuser to tie it all in.

Now you just need a video clip so I can hear this!

MikeE92M3 · 10-11-2012, 09:53 AM

Quote:

Originally Posted by dmk08

Now you just need a video clip so I can hear this!

I will as soon as I can, bro! I will take one from inside the car too which is where I noticed the biggest change and it is where I am all smiles

jpirelli · 10-11-2012, 11:32 AM

Why are they crooked?

MikeE92M3 · 10-11-2012, 12:01 PM

Quote:

Originally Posted by jpirelli

Why are they crooked?

Must be how they look in the pictures. Everything was measured to be perfectly straight and level. Regardless, I need a diffuser to clean everything up.

DB · 10-11-2012, 12:18 PM

How did you determine the necessary length of the helmholtz chambers? Thanks for sharing all of this.

MikeE92M3 · 10-11-2012, 12:45 PM

Quote:

Originally Posted by DB

How did you determine the necessary length of the helmholtz chambers? Thanks for sharing all of this.

I used a formula that I had seen on another thread for a different car (350z) Formula is V/WV (Velocity/Wavelength) standard.

V=1187 Ft/Sec for soundwaves (standard wavelength speed)

You have to find out what frequency (Hz) your drone is prevalent at. I measured anywhere from 160-180 hz, depending on what gear, in my car. So Lets say 165-175 Average. I will do 175 for the purpose of this solution.

1187(wavelength)/175 (hz, drone frequency) = 6.78

Take 6.78, divide it by 4 (conversion) (6.78/4) and you have 1.69 feet (14 inches)

The pipe needs to be at least 14 inches to cancel out the drone.

Hope this makes sense. It took me a few minutes to grasp it but once you measure the drone frequency with a microphone or app (I used a HZ app on my iphone), it is easy to do the math from there.

ROB_S2K · 10-22-2012, 12:03 PM

Great thread, very informative. Question for you is there a hole at the end of the capped off resonator? Seems like there is one right in the middle of the cap.

MikeE92M3 · 10-22-2012, 01:52 PM

Quote:

Originally Posted by ROB_S2K

Great thread, very informative. Question for you is there a hole at the end of the capped off resonator? Seems like there is one right in the middle of the cap.

Nope, no holes. Fender washers were used to cap the ends, and there was a tiny hole that was welded shut, which is probably why it looks to be that way.

ArthurJGuy · 10-23-2012, 12:06 PM

I've been a long time fan of Magnaflow, any sound clips?

dmk08 · 10-23-2012, 12:11 PM

Quote:

Originally Posted by ArthurJGuy

I've been a long time fan of Magnaflow, any sound clips?

Yeah!! Where are the clips!!

*starts lynch mob outsides Mikes office*

MikeE92M3 · 10-23-2012, 03:00 PM

Quote:

Originally Posted by dmk08

Yeah!! Where are the clips!!

*starts lynch mob outsides Mikes office*

SOON!!! Haha! I will be home next weekend and I can make a nice clip of various driving and RPM ranges. I will be sure to let you all know when it is done

MStar · 10-23-2012, 03:56 PM

Quote:

Originally Posted by jpirelli

Why are they crooked?

I noticed this with most aftermarket setups on this car (even really high end setups)..the tips and spacing around the bumper cover never look quite as aligned as OEM..

positiveions · 10-23-2012, 04:31 PM

Looks good.

malaysiantransporter · 10-23-2012, 07:03 PM

1.69ft is more than 14inches by my calculator...?

MikeE92M3 · 10-23-2012, 07:27 PM

Quote:

Originally Posted by malaysiantransporter

1.69ft is more than 14inches by my calculator...?

Haha it may have been off slightly, but it was the minimum needed. If you need to cancel out a certain frequency and it requires 12.45 inches or whatever, anything from that and longer will be successful.

I have Turner Test Pipes ordered and cannot wait for them to come in

10-05-2012, 04:54 PM	#1
MikeE92M3 Lieutenant Drives: 08 E92 M3 Join Date: May 2012 Location: Richmond, VA Posts: 581 iTrader: (5)	So I started a thread about custom Magnaflow mufflers... And this will be the finish. Got everything installed today on my day off. As some of you may remember, I had installed the Magnaflow 14816 Mufflers and while I loved how it sounded, the drone was a bit much. My solution consisted of ordering a Magnaflow True X pipe, Aero AR25 Resonators, and OBX generic resonators. Why? I was going full custom. I already had my secondary cats taken off and replaced with straight pipes for those who had seen my post a few months back. To solve the drone issue, I used the helmholtz formula to create helmholtz chambers to cancel out the drone frequencies. This is what the OBX universal 2.5" resonators were for. For those who don't know, the OEM x pipe is crap--there is just a small "hole" where the exhaust gasses are supposed to crossover. Compared to the new magnaflow X pipe, this one was wide open. I already knew there were gonna be some positives with the new X pipe once I compared the two. The resonators replaced the OEM ones just past the x pipe. They fit perfectly. I had my tech create new pipes from the resonators back to the mufflers. Very straight through design with very few bends. He tried to make both of them perfect, and I think he did. The helmholtz chambers were created just as they are meant to perform, I needed roughly 13 inches to cancel out the frequencies, and they are placed where they belonged. I used the AA exhaust as a reference for the location where the pipes were to come off a 90 degree angle. 3 hours later, my new exhaust was done. The result? Absolutely little to no rasp, ZERO drone, and Immediate notice of more "pick up" with the new x pipe. He polished up the welds, especially on the helmholtz chambers, and they look fantastic. Really aggressive from behind. I absolutely love it and it is the most perfect thing I have heard besides women's sexual moans. Let's not go there. Of course, I will provide pictures and stand by for a sound clip either tomorrow or Sunday. I spent about $800 overall on EVERYTHING, including labor and parts. Couldn't be happier. Pics: __________________ 2008 (07/08) E92 M3 BPM Stage II Tuned by Mike Benvo, 6MT, Turner Test Pipes, Magnaflow Custom Catback Exhaust (Magnaflow X Pipe, secondary cat delete, Aero Resonators and Helmholtz Chambers),Vorsteiner CF Lip, Hamann Style CF rear diffuser, CF Rear Decklid Spoiler, BMW Performance Kidney Grills, CF Side Grills, OEM GTS Wheels, K&N Drop-In Filter, GP Thunder 8k Angel Eyes, Painted Reflectors.
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10-05-2012, 07:38 PM	#2
ZRODDICK Private First Class Drives: WHITE E92 M3 Join Date: Nov 2011 Location: BROOKVILLE,NY Posts: 173 iTrader: (0) Garage List 2008 BMW M3 [5.00]	Great job! Could you come up with a vadio? __________________ AW E92 M3 08 DCT RPI GTM&AFE Stg2 BBS

10-05-2012, 08:14 PM	#3
BMRLVR Grease Monkey Drives: 2011 E90 M3,1994 Euro E36 M3/4 Join Date: Apr 2006 Location: Fort McMurray, Alberta, Canada Posts: 2,035 iTrader: (3)	Happy you like it! __________________ 2011 E90 M3 ZCP - Individual Moonstone/Individual Amarone Extended/Individual Piano Black With Inlay:LINK!!! 1994 Euro E36 M3 Sedan - Daytona Violet/Mulberry:LINK!!!

10-07-2012, 11:41 PM	#7
MikeE92M3 Lieutenant Drives: 08 E92 M3 Join Date: May 2012 Location: Richmond, VA Posts: 581 iTrader: (5)	Now I just need to get a rear diffuser to tie it all in. __________________ 2008 (07/08) E92 M3 BPM Stage II Tuned by Mike Benvo, 6MT, Turner Test Pipes, Magnaflow Custom Catback Exhaust (Magnaflow X Pipe, secondary cat delete, Aero Resonators and Helmholtz Chambers),Vorsteiner CF Lip, Hamann Style CF rear diffuser, CF Rear Decklid Spoiler, BMW Performance Kidney Grills, CF Side Grills, OEM GTS Wheels, K&N Drop-In Filter, GP Thunder 8k Angel Eyes, Painted Reflectors.

10-22-2012, 12:03 PM	#14
ROB_S2K Lieutenant Colonel Drives: 2012 LSB E92 M3 Join Date: Apr 2005 Location: Los Angeles Posts: 1,557 iTrader: (2)	Great thread, very informative. Question for you is there a hole at the end of the capped off resonator? Seems like there is one right in the middle of the cap. __________________ 2012 \| Laguna Seca Blue \| Rust Brown \| Individual \| 6MT

10-07-2012, 01:08 PM	#4
e46kyle New Member Drives: E46 Join Date: Oct 2012 Location: cali Posts: 5 iTrader: (0)	would love to hear how this sounds

10-11-2012, 11:32 AM	#10
jpirelli No, I don't want to text you "bro" Drives: E90 M3, E92 335i, E90 325i Join Date: Apr 2009 Location: Car Posts: 767 iTrader: (3)	Why are they crooked?

10-11-2012, 12:18 PM	#12
DB e90m3/e92 335xi Drives: e90 m3 Join Date: Mar 2010 Location: Philly Posts: 85 iTrader: (0)	How did you determine the necessary length of the helmholtz chambers? Thanks for sharing all of this.

10-23-2012, 12:06 PM	#16
ArthurJGuy Private Drives: e46 beater, e92 ///M shopping Join Date: Oct 2012 Location: Las Vegas, NV Posts: 57 iTrader: (0)	I've been a long time fan of Magnaflow, any sound clips?

10-23-2012, 04:31 PM	#20
positiveions Major General Drives: 09 MKV JETTA 2.5 & E90 M3 :) Join Date: Sep 2007 Location: La Verne, CA Posts: 9,032 iTrader: (1)	Looks good. __________________

10-23-2012, 07:03 PM	#21
malaysiantransporter New Member Drives: 2008 E92 M3 Join Date: Oct 2012 Location: Malaysia Posts: 17 iTrader: (0)	1.69ft is more than 14inches by my calculator...?

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