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      12-04-2019, 10:53 AM   #507
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Quote:
Originally Posted by Kilabyte View Post
^ When you guys mention the stock muffler does that include the MPE? I'm assuming yes if it's design is the same and it's simply louder than stock.
I'd like to think that the MPE muffler was also designed with stock length pipes and tone characteristics in mind. Anybody's guess how long it took to develop it (unless this is documented somewhere). I personally have never heard MPE in person, so can't really speak to how it sounds. All i know is I hate the sound that video sound clips capture of MPE.

I don't think chambered mufflers are the answer for this specific application of equal length pipes though - unless a sound engineer can measure the frequencies of equalized lengths and develop a chambered muffler specifically to work with it. Which nobody is going to do without some serious resources. Usually just easier to use simple packed directional mufflers and modify according to tone and drone properties.

I just realized the Active Autowerke signature single entrance muffler would be the perfect muffler to connect to my single pipe merge. It has a valve, and pass through for a muffler, with plenty of space to add additional mufflers or resonators. If only I could source just the muffler - not going to pay for a full exhaust which costs more than my entire fabbed system just to hack up the muffler
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      12-04-2019, 11:40 AM   #508
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Its hard to say regarding the OE or MPE (or any exhaust really)

the sound that's currently being captured with a mic up close to the exhaust isn't capturing the true exhaust note because of how sound waves travel and capturing the true balanced exhaust pulses smoothing themselves out, you have to get the exhaust from a distance to get a better idea of how the exhaust sounds like.

Really the only way is if someone follows you from a small distance while you accelerate or do a stationary rev from at least 4 car lengths back, but exhausts sound different under load.
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      12-04-2019, 11:49 AM   #509
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Quote:
Originally Posted by spool twice View Post
Its hard to say regarding the OE or MPE (or any exhaust really)

the sound that's currently being captured with a mic up close to the exhaust isn't capturing the true exhaust note because of how sound waves travel and capturing the true balanced exhaust pulses smoothing themselves out, you have to get the exhaust from a distance to get a better idea of how the exhaust sounds like.

Really the only way is if someone follows you from a small distance while you accelerate or do a stationary rev from at least 4 car lengths back, but exhausts sound different under load.

Solution: Record from a Tesla so no new engine/exhaust noise is introduced, and follow M3/4 from 4 lengths behind
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      12-04-2019, 04:33 PM   #510
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Quote:
Originally Posted by ntg44 View Post
Solution: Record from a Tesla so no new engine/exhaust noise is introduced, and follow M3/4 from 4 lengths behind


I'm going to start a new thread to not cloud this one, and easier for searching for other members.

Last edited by spool twice; 12-04-2019 at 04:45 PM..
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      12-05-2019, 01:42 AM   #511
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Quote:
Originally Posted by ntg44 View Post
I just realized the Active Autowerke signature single entrance muffler would be the perfect muffler to connect to my single pipe merge. It has a valve, and pass through for a muffler, with plenty of space to add additional mufflers or resonators. If only I could source just the muffler - not going to pay for a full exhaust which costs more than my entire fabbed system just to hack up the muffler
Home page says they are made to order. If you ask them maybe it's possible to order without the midpipe.
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      12-05-2019, 05:15 AM   #512
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Great thread...

Quote:
Originally Posted by behindthen0thing View Post
As I mentioned before, if it's just the exhaust pulses hitting at a certain time, wouldn't adding 7 inches have a similar effect as adding 14? You're just adjusting the timing of the pulses so I would think that you could scoot them over enough just by tuning the length. Maybe it doesn't necessarily need to be the same length, just a length that will allow the exhaust pulses to exit in an even timing
Just to pick up on other posts, the exhaust must be equal length before merging (or equal length to tailpipe if no merge / crossover) to keep the audible pulses in 120deg firing angle timing accross the entire rev range.

If you have unequal lengths before merge the pulse timing at the merge point and therefore the tailpipes will vary with engine speed so the sound pattern will change with rpm (as S55 does).

So it is pointless to go any other way than equal length before merge (as manufacturers have done for years, but obviously BMW forgot for cost / packaging reasons on the S55)

Last edited by doughboy; 12-05-2019 at 05:21 AM..
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      12-05-2019, 05:57 AM   #513
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Hey everyone,

It may be a little too late for this, but better to move any equal length discussion to spool twice's new thread - it'll be easier to reference for existing and new members.

https://f80.bimmerpost.com/forums/sh....php?t=1675268

Again, apologies to RevNev for hijacking your thread, but you did inspire us to pursue tonal variation with the exhaust, so that's still all on you. Your solution is just as unique and awesome - I think you've added so much character to the "standard" S55 exhaust note without going equal length - your car really comes alive at high RPMs.

To everyone else pursuing equal length designs, talk to you in the other thread.
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      02-06-2020, 01:44 AM   #514
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Quote:
Originally Posted by RevNev View Post
The S55 M3/M4 engine sounds farty and raspy for 2 reasons. The farty V6 twin exhaust sound is caused by the exhaust manifold split with twin turbos and isolated outlets and the 2 midpipes needs to be joined into 1 to blend out the farty V6 note and this is what AA etc do with the single midpipe.

The raspiness is caused by stock resonator being too small and not packed with sound deadening so it's an open chamber resonator with an H pipe that emphasises raspiness. To get rid of the raspiness you "must" use perforated tube resonators packed with sound deadening preferably stainless wool as it doesn't burn out like fibreglass.

With catless downpipes, you need 4 12" resonators 4" diameter in the midpipe to control noise with the valves open and create a smooth rasp free note. The reason all the aftermarket exhausts sound nearly as bad as stock but louder, is they don't use resonators or the resonators they use are too small and not packed with effective sound deadening material.

This setup sounds magic with catless downpipes and stock rear muffler but unfortunately it seems that everyone is trying to get a decent note out of the S55 exhaust with straight un-resonated pipe and it's impossible! This is simply "old school" exhaust technology I've used to make V8's sound great that works just the same on the S55 engine as I expected.
Hey man, appreciate your input here. Could you recommend specific brands?
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      02-16-2020, 12:25 PM   #515
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Quote:
Originally Posted by LOW4LYF View Post
I stopped reading after you said V6 😂😂😂
Ditto
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      02-16-2020, 12:35 PM   #516
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I have an awe non res exhaust and it sounds bad ass
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      02-16-2020, 01:14 PM   #517
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why is rasp bad?
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      02-16-2020, 01:45 PM   #518
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Quote:
Originally Posted by deeldoo View Post
why is rasp bad?
Rasp being bad is purely subjective and based on preference. Some like it, majority think it sounds terrible. Our cars are fast but don't sound what we associate with cool sports cars.
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      02-16-2020, 01:51 PM   #519
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Quote:
Originally Posted by Yessir View Post
Quote:
Originally Posted by deeldoo View Post
why is rasp bad?
Rasp being bad is purely subjective and based on preference. Some like it, majority think it sounds terrible. Our cars are fast but don't sound what we associate with cool sports cars.
I mean i guess, I personally think M cars sound distinct and unique
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      02-18-2020, 08:57 PM   #520
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So it looks like ActiveAutowerke has also made a good sounding exhaust.
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      02-18-2020, 09:41 PM   #521
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Quote:
Originally Posted by TimmyM56 View Post
Video from ActiveAutowerke Instagram

So it looks like ActiveAutowerke has also made a good sounding exhaust.
That sounds insane
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      02-19-2020, 12:27 AM   #522
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I'm hoping that just needs a better mic, I want it to sound deep and clean not raspy
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S55, 2JZ, M48.00
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      02-19-2020, 09:19 AM   #523
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Quote:
Originally Posted by TimmyM56 View Post


So it looks like ActiveAutowerke has also made a good sounding exhaust.
And Valvetronic!

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