MPE Muffler and Downpipes only?

[Izzmeister]

Hi guys, I've got an F82 with a stage 1 tune. Came across a great deal on evolution racing cat-less downpipes. What do you guys think about leaving the factory mid-pipe and adding an MPE muffler? I don't want the car to be too loud. That's why I'm leaving the mid-pipe. Does the MPE muffler really make it sound better? Valves open all the time isn't straight thru? On the fence about it. If it really doesn't do much for sound then maybe I should just keep the stock muffler and get the mid-pipe? Thoughts...Thank you

[satinghostrider]

It will be about 30% more louder and introduce more rasp but with the factory mid-pipe I think it should be fine. I am also looking to add a downpipe with it and am on the fence.

Hope more people can chime in on going catless with the MPE leaving the stock mid-pipe intact. I would specifically like to know about rasp and drone and if it is as bad as it sounds. Sure you will get about 20-30hp more with a tune I think.

[CanAutM3]

You should . There's tons of info on this topic on the forum.

The MPE differs from the standard and sport exhaust because it replaces the mid resonator with an H-pipe. Further, the rear section design is quite different and the exhaust gas does not flow through the rear silencer when the valves are open. Also, even if it is "straight through" with the valves open, the design of the rear section will change the tone of the exhaust due to the Helmholz chamber effect (think blowing over bottles).

[MisterBrigante]

@Op; i’ve had this setup and to be honest, Irans to raspy. Sounds like a Honda imo.
Went back to stock cat’s now.

[RevNev]

Originally Posted by CanAutM3

You should . There's tons of info on this topic on the forum.

The MPE differs from the standard and sport exhaust because it replaces the mid resonator with an H-pipe. Further, the rear section design is quite different and the exhaust gas does not flow through the rear silencer when the valves are open. Also, even if it is "straight through" with the valves open, the design of the rear section will change the tone of the exhaust due to the Helmholz chamber effect (think blowing over bottles).

The mid pipe resonator is virtually the same design as the MPE except for some perforations. Unless the unpacked resonator shell creates turbulence, the MPE mid pipe would only be louder without the Helmholz effect.

[Izzmeister]

Originally Posted by RevNev

The mid pipe resonator is virtually the same design as the MPE except for some perforations. Unless the unpacked resonator shell creates turbulence, the MPE mid pipe would only be louder without the Helmholz effect.

What I'm wondering is for the mpe muffler only. I have cat-less downpipes I haven't installed yet. Once I change the downpipes do you think it's worth it to switch the stick muffler for the mpe. Mid-pipe stays as factory mid-pipes with cats. I just don't want to sound like a honda or be unbearably loud with a drone in the cabin. That's my reasoning for keeping the factory mid-pipes. The mpe muffler has diff baffling inside and I believe it's made of a diff metal. Being that when the valves are open both the factory muff and mpe(comp pack muffler) both come thru as a straight pipe, does it make sense ro change to the mpe muff? Will it sound better than stock muff?

[ntg44]

Originally Posted by Izzmeister

What I'm wondering is for the mpe muffler only. I have cat-less downpipes I haven't installed yet. Once I change the downpipes do you think it's worth it to switch the stick muffler for the mpe. Mid-pipe stays as factory mid-pipes with cats. I just don't want to sound like a honda or be unbearably loud with a drone in the cabin. That's my reasoning for keeping the factory mid-pipes. The mpe muffler has diff baffling inside and I believe it's made of a diff metal. Being that when the valves are open both the factory muff and mpe(comp pack muffler) both come thru as a straight pipe, does it make sense ro change to the mpe muff? Will it sound better than stock muff?

M Performance exhaust is made from Titanium, and does not bolt up directly to stock midpipe due to MPE muffler connection design. Which means you're going to need custom fab work if you only buy the muffler without the midpipe section. Not only that, but with catless unresonated downpipes, your car will sound like a pissed off bee stuck inside a beer can - just don't do it. It's raspy enough stock.

If you're interested in the custom fab route, the best you're going to make your car sound is to weld in some resonators or get AA/VRSF single midpipe. Most people including myself swap resonators in where the secondary cats are on stock midpipe, but maybe there's room just before the muffler portion where you can weld them in - would need to double check this though.

[RevNev]

Originally Posted by ntgarage44

If you're interested in the custom fab route, the best you're going to make your car sound is to weld in some resonators or get AA/VRSF single midpipe. Most people including myself swap resonators in where the secondary cats are on stock midpipe, but maybe there's room just before the muffler portion where you can weld them in - would need to double check this though.

The best note I've had from the F8X is joining the midpipes together at the bend before the secondary cats in an oval section about 5" long. The secondary cats and resonator I replace with 4 round perforated tube resonators 12" long 4" in diameter packed with stainless wool. With catless downpipes retaining the stock rear muffler, they're quite enough with the vales closed and loud enough and smooth with the valves open and sounds more like a typical inline 6 with a single exhaust than the raspy V6 farty split header note of the stock exhaust.

4 resonators I fabricate (below) out of 4" 409 stainless exhaust tube.

[Izzmeister]

Originally Posted by RevNev

The best note I've had from the F8X is joining the midpipes together at the bend before the secondary cats in an oval section about 5" long. The secondary cats and resonator I replace with 4 round perforated tube resonators 12" long 4" in diameter packed with stainless wool. With catless downpipes retaining the stock rear muffler, they're quite enough with the vales closed and loud enough and smooth with the valves open and sounds more like a typical inline 6 with a single exhaust than the raspy V6 farty split header note of the stock exhaust.

4 resonators I fabricate (below) out of 4" 409 stainless exhaust tube.

That looks really good. So you have pics of the exhaust on or off the car or a video of the sound? I was going to install catless dp, AA mid and the mpe muffler but have a feeling it will be unbearable. I definitely need a resonator somewhere in there to tune the fart can noise out. Doesn't the AA mid join the two pipes into one for that same reason, to get rid of that lawnmower sound?

[RevNev]

Originally Posted by Izzmeister

That looks really good. So you have pics of the exhaust on or off the car or a video of the sound? I was going to install catless dp, AA mid and the mpe muffler but have a feeling it will be unbearable. I definitely need a resonator somewhere in there to tune the fart can noise out. Doesn't the AA mid join the two pipes into one for that same reason, to get rid of that lawnmower sound?

I'm doing another one at the moment and will post pics and sound video when it's finished.

The AA midpipe gets rid of the farty V6 sound, but they're still raspy and loud with catless down pipes and there's no room for resonators. They "must" have perforated tube packed resonators in the midpipe to smoothen the note.

When the valves are open with catless downpipes and an un-resonated midpipe, there's no muffling capacity and it's virtually straight pipe and that's why they sound awful. Straight pipe never sounds good, it's just loud.

[Izzmeister]

Originally Posted by RevNev

I'm doing another one at the moment and will post pics and sound video when it's finished.

The AA midpipe gets rid of the farty V6 sound, but they're still raspy and loud with catless down pipes and there's no room for resonators. They "must" have perforated tube packed resonators in the midpipe to smoothen the note.

When the valves are open with catless downpipes and an un-resonated midpipe, there's no muffling capacity and it's virtually straight pipe and that's why they sound awful. Straight pipe never sounds good, it's just loud.

Makes sense, what resonator to choose though? You would have to know what frequency you're canceling in the exhaust note to pick the right resonator. I would hate to cut up an expensive mid-pipe. Maybe installing the resonators in the last section of the exhaust before the muffler?

[ntg44]

Originally Posted by Izzmeister

Makes sense, what resonator to choose though? You would have to know what frequency you're canceling in the exhaust note to pick the right resonator. I would hate to cut up an expensive mid-pipe. Maybe installing the resonators in the last section of the exhaust before the muffler?

I installed Magnaflow 14156 resonators, as many others have. Others have chosen Vibrant resonators. Replacing secondary cats with these was the best exhaust mod ever, and for only $300 with install.

I went a step further and found a second hand stock midpipe, replaced secondary cats with resonators on the spare pipe, and cut & clamped it in the same general area as MPE hookup to my stock exhaust. That way, both pipes are the same length, and I can swap in stock pipe, cut, clamp, and sell the aftermarket pipe if I wanted to. It's an awesome mod, and sounds great with valves unplugged to stay open. This isn't quantitative, but in my opinion, it sounds like 90% of rasp was eliminated. Having an exhaust tone is nice. I can floor it under bridges and around concrete barriers without cringing now, and actually enjoy it.

[RevNev]

Originally Posted by Izzmeister

Makes sense, what resonator to choose though? You would have to know what frequency you're canceling in the exhaust note to pick the right resonator. I would hate to cut up an expensive mid-pipe. Maybe installing the resonators in the last section of the exhaust before the muffler?

I cut up second hand midpipes and leave the original exhaust in tact particularly if the car's under warranty. Second hand exhausts in near new condition pop up often for sale in Australia for around $300 to $500 AUD.

Perforated tube mufflers packed with stainless wool or fibreglass produce the smoothest note on any engine. It's just that you need multiple of bigger mufflers in this design for noise control. Stainless wool packing is louder than fibreglass but it doesn't burn out, that's why I need 4 resonators in the midpipe or 24" of resonator on each pipe with catless down pipes to keep the noise under control on the street with the valves open.

[Izzmeister]

Originally Posted by ntgarage44

I installed Magnaflow 14156 resonators, as many others have. Others have chosen Vibrant resonators. Replacing secondary cats with these was the best exhaust mod ever, and for only $300 with install.

I went a step further and found a second hand stock midpipe, replaced secondary cats with resonators on the spare pipe, and cut & clamped it in the same general area as MPE hookup to my stock exhaust. That way, both pipes are the same length, and I can swap in stock pipe, cut, clamp, and sell the aftermarket pipe if I wanted to. It's an awesome mod, and sounds great with valves unplugged to stay open. This isn't quantitative, but in my opinion, it sounds like 90% of rasp was eliminated. Having an exhaust tone is nice. I can floor it under bridges and around concrete barriers without cringing now, and actually enjoy it.

Are those magnaflow resonators packed with steel wool? A sound clip would be awesome. Did you post that also swapped the one resonator at the end for a magnaflow x pipe? I'm really leaning towards changing the cats in the midpipe if it will sound better. I hate the fart can noise.

[ntg44]

Originally Posted by Izzmeister

Are those magnaflow resonators packed with steel wool? A sound clip would be awesome. Did you post that also swapped the one resonator at the end for a magnaflow x pipe? I'm really leaning towards changing the cats in the midpipe if it will sound better. I hate the fart can noise.

I wouldn't lie or exaggerate to justify my purchase. Unfortunately, no microphone I have can record the exhaust without the audio clipping. But I wouldn't be recommending it if I didn't feel it was an improvement. For $300 including install, you can't go wrong. If your only intent is to fix the exhaust rasp, 2nd cat swap for these magnaflows will 100% do the trick the cheapest. And unplug valves if you want it louder. Aside from cold start which is nuts, it sounds awesome all the time. And believe it or not, with less drone than stock.

[RevNev]

Originally Posted by ntgarage44

I wouldn't lie or exaggerate to justify my purchase. Unfortunately, no microphone I have can record the exhaust without the audio clipping. But I wouldn't be recommending it if I didn't feel it was an improvement. For $300 including install, you can't go wrong. If your only intent is to fix the exhaust rasp, 2nd cat swap for these magnaflows will 100% do the trick the cheapest. And unplug valves if you want it louder. Aside from cold start which is nuts, it sounds awesome all the time. And believe it or not, with less drone than stock.

The resonators get rid of the raspy note and this mod (below) joining the midpipes on the bend before the secondary cats, gets rid of the V6 farty spilt system note and sounds like an AA single midpipe.

[Izzmeister]

Originally Posted by RevNev

The resonators get rid of the raspy note and this mod (below) joining the midpipes on the bend before the secondary cats, gets rid of the V6 farty spilt system note and sounds like an AA single midpipe.

So your set-up is Magnaflow resonators replacing the cats and joining the midpipes at the bend? What about the rear resonator? I can have my exhaust guy weld me an x where you joined your pipes. Now the rear resonator gets replaced with what? Do you have a sound clip? The only exhaust I've heard that I really like is the Milltek. Everything else is ok for the most part. Usually in line 6 cars have a single pipe all the way thru to a long muffler. I don't know why it's so hard to make these cars sound decent. Everything else I love about it but the exhaust, not very M.

[RevNev]

Originally Posted by Izzmeister

So your set-up is Magnaflow resonators replacing the cats and joining the midpipes at the bend? What about the rear resonator? I can have my exhaust guy weld me an x where you joined your pipes. Now the rear resonator gets replaced with what? Do you have a sound clip? The only exhaust I've heard that I really like is the Milltek. Everything else is ok for the most part. Usually in line 6 cars have a single pipe all the way thru to a long muffler. I don't know why it's so hard to make these cars sound decent. Everything else I love about it but the exhaust, not very M.

I fabricate resonators to replace the secondary cats and stock resonator. The Magnaflow resonators are too small and loud for catless down pipes. They're only 6" long and mine like the Milltek resonators are 12" long and 4" round. With catless down pipes, I've got 24" of resonator on each pipe.

It's not hard to dramatically improve the note but the problem is; everyone does the same thing copying exhausts with lousy notes. It's like running a twin 2.5" system on a V8 with no balance pipe and no mufflers and that sounds just as lousy as the majority of M3/M4 systems on the market.

I'm only concerned how it sounds with the valves open at full noise and the quieter the better with the valves closed. Other than weight saving, rear mufflers are a waste of money and the power gain and note's in the pipework before the rear muffler.



V8's sound lousy too with exhaust designs most use on the M3/M4. You can't run split systems and straight (un-resonated) pipe on any engine and expect it to sound good.