Aftermarket mufflers - power loss?

[Obioban]

You will not gain power from an aftermarket muffler.
You may lose power from an aftermarket muffler (el diablo being the most notorious for this).
95% of aftermarker mufflers will make the car drone (dinan, scorza, and SS Street being the only exceptions I have experienced).
You may screw up the rear of car aerodynamics with an aftermarket muffler (all the small/light ones, with no supplemental mods done to counter, give the car parachute pants).
you can remove weight from the car with a muffler... but it's the worst possible location to do so, on the entire car (back of the car, on a car that is always fighting to keep weight off the front, and at the lowest point (raising your COG).

... moving to the subjective, basically every exhaust for the e46 M3 sounds terrible. If you want a good sounding e46M, you want the quietest muffler possible and a CSL intake.

[Grey Phox]

A good thought process might be to assume that a majority of aftermarket mufflers wont improve power(rather than lose power) and consider sound as an enjoyment improvement depending on what you like.

Re: discrete power gain/loss. I know an e46 m3 is not a rocket by modern standards but it's still a very fast road car on modern tires. Some of y'all's speed/power comments make me glad I will rarely share public roads with you if you're really approaching the limits of this platform on the street.

I only meant what I said as a comparable for the power of the car itself. I cruise around with it, do some "spirited" driving here and there but that's about it. I drive for a living (CDL) and its not worth risking that or anybody's life (mine or others) If i want to do that dumb stuff I'll find an auto-x or a track. That and my daughter loves my car so I take her with me half the time and just hit back roads. Shes 3........and she's the one yelling for me to go faster.

I know this isn't a sound thread either, but to give you an idea, on a 30 minute drive around on Saturday my daughter happen to fall asleep (probably within 15 minutes).......That's with an El Diablo.......so it should tell you it's not super loud at all. That or I'm one slow ass driver now.

As much as I like the way my car sounds and certain particular setups I've heard, Obioban is kinda right too. Many of these exhausts sound like ass on this car. Stock has a place alot of the time. Some setups that people are running are so loud with no tone at all.

[Cronenberged]

I believe the original El Diablo’s power loss is due to that terrible welded bend that’s a point on the right side. The Caliente version with wider diameter should fix that as the bend had to be rounded, but I haven’t seen a dyno
or data for it.

[oceansize]

I have the Diablo and the RE rasp pipes but I'm FI, and it sounds so good in comparison to most others I don't care. There is drone from 2k to 3k, but I'm in a convertible, so again, its all good.

[Cronenberged]

I have the Diablo and the RE rasp pipes but I'm FI, and it sounds so good in comparison to most others I don't care. There is drone from 2k to 3k, but I'm in a convertible, so again, it’s all good.

I get the same drone from my Dixis but it’s between 2-2.8k

[bavarian3]

You will not gain power from an aftermarket muffler.
You may lose power from an aftermarket muffler (el diablo being the most notorious for this).
95% of aftermarker mufflers will make the car drone (dinan, scorza, and SS Street being the only exceptions I have experienced).
You may screw up the rear of car aerodynamics with an aftermarket muffler (all the small/light ones, with no supplemental mods done to counter, give the car parachute pants).
you can remove weight from the car with a muffler... but it's the worst possible location to do so, on the entire car (back of the car, on a car that is always fighting to keep weight off the front, and at the lowest point (raising your COG).

... moving to the subjective, basically every exhaust for the e46 M3 sounds terrible. If you want a good sounding e46M, you want the quietest muffler possible and a CSL intake.

I can verify first hand there is some truth to this.

Funny story from the OG days - we weren't barely around 18-20yo's at the time, but a buddy of mine would pull his muffler and drove around without it sometimes for shits. He decided to roadtrip that way to Bimmerfest(Santa Barbara) one year. Those caravans in the early days were pure hooliganism. Needless to say, particularly high speeds, and no muffler = a decimated rear bumper cover. I have pictures on a hard drive somewhere. Good old days...

[Avedis]

Stock exhaust with upgraded tips, paired with Karbonius CSL intake. You’ll never even think of exhaust when you drive it.

[CrisSilberGrau]

Agreed. If you're trying to prepare with a good section 3 for doing headers & section 1 later on, it may make sense.

OM Scorza is supposed to make power, I'm not sure about the sgt version, but since it's just a carryover it should also have limited power gains. There were some quality concerns back then, but I bought my OM Scorza used on the old forums 11 years ago and it's still running good after countless trackdays.

Every other track M3 here in Germany is running the Supersprint race, so those will also be good for power.

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Went from SCZA to SS Race (the new 63.5mm one will post in my journal one of these days), all things remaining the same as in my sig, can confirm butt dyno feels an increase above 6k. The dual SS Res does quiet down the car considerably over other setups with the OEM Sec 2. The SS tips are the best in the biz imo, iconic.

Considerably louder at WOT above 4k, around town similar sound levels to the SCZA.

[bavarian3]

Went from SCZA to SS Race (the new 63.5mm one will post in my journal one of these days), all things remaining the same as in my sig, can confirm butt dyno feels an increase above 6k. The dual SS Res does quiet down the car considerably over other setups with the OEM Sec 2. The SS tips are the best in the biz imo, iconic.

Considerably louder at WOT above 4k, around town similar sound levels to the SCZA.

True that, supersprint race tips under a proper csl diffuser is just right.

[Obioban]

I had my SS street muffler custom made with SS race tips

[George Hill]

I bought my AW M3 with a Scorpion muffler and I compared it to stock and no muffler back to back on the dyno. Same day, we swapped them right there on the dyno itself.

Brown - Scorpion - 283/235
Green - No Muffler - 293/238
Orange - Stock BMW - 298/240

[paulclaude]

I bought my AW M3 with a Scorpion muffler and I compared it to stock and no muffler back to back on the dyno. Same day, we swapped them right there on the dyno itself.

Brown - Scorpion - 283/235
Green - No Muffler - 293/238
Orange - Stock BMW - 298/240

I had the exact same findings when testing the Scorpion rear section a few years back, and also on a few customer cars. Some kind of restriction in that silencer somewhere for sure.

[oceansize]

Why does no muffler have less power?

[bavarian3]

I bought my AW M3 with a Scorpion muffler and I compared it to stock and no muffler back to back on the dyno. Same day, we swapped them right there on the dyno itself.

Brown - Scorpion - 283/235
Green - No Muffler - 293/238
Orange - Stock BMW - 298/240

Wow. I knew someone out there had data. That's a much bigger difference than "just a few unnoticeable hp"

[George Hill]

Why does no muffler have less power?

Honestly have no idea, these were the "averages" from each scenario, not just a one and done so we definitely backed it up. Maybe has to do with turbulence behind the bumper? Or maybe the longer piping (muffler) just helps with scavenging? I bet someone smarter than myself will chime in with a reasonable explanation. lol