m3 exhaust in 328?

[mig328]

Im looking at a m3 exhaust, thinking about buying it to put on my 328. Im not sure if I need the midsection part of the m3 exhaust as well or will it simply bolt on to my 328 midsection? i know some of you on here have done it so do I need the whole setup?

[Lailoken]

The cat-back m3 exhaust bolts right up. Have it on my 328.

I kinda wish I'd gone with something a little louder now though, Stromung, Supersprint or whatever.

M3 exhaust has a quiet-ish but refined tone, and it looks pretty cool.

[mig328]

yea id like one of those too but I cant find a decent one for cheap!! ill haveto settle w the m3 exhaust for now. is it really a noticeable difference in sound?

[Mitch]

for what it's worth: the m3 exhaust is heavier than your stock 328 exhaust, and since it doesn't actually flow all that much better, there is no net "performance gain" at all.

When people get aftermarket exhausts, while they typically are worth 5-8hp depending on the exhaust and the company, the actual gain comes from the weight reduction, sometimes as much as 25lbs.

[Nataliator]

for what it's worth: the m3 exhaust is heavier than your stock 328 exhaust, and since it doesn't actually flow all that much better, there is no net "performance gain" at all.

When people get aftermarket exhausts, while they typically are worth 5-8hp depending on the exhaust and the company, the actual gain comes from the weight reduction, sometimes as much as 25lbs.

+1, the m3 exhaust actually restricts flow more than stock on any non-M3 car.

[RamGoat]

for what it's worth: the m3 exhaust is heavier than your stock 328 exhaust, and since it doesn't actually flow all that much better, there is no net "performance gain" at all.

When people get aftermarket exhausts, while they typically are worth 5-8hp depending on the exhaust and the company, the actual gain comes from the weight reduction, sometimes as much as 25lbs.

on the contrary, the M3 exhaust piping is about a quarter of an inch wider than the stock 325 and the 328s piping but is way heavier...

25lbs more or less isnt going to affect the cars performance

i read somewhere that 100lbs=.10

every 100lbs equals a tenth of a second more or less on your 1/4 mile

[RamGoat]

+1, the m3 exhaust actually restricts flow more than stock on any non-M3 car.

-1 i dont see how wider pipes restrict airflow

[Mitch]

-1 i dont see how wider pipes restrict airflow

Do you know how a traditional baffled muffler works? Pipe width means absolutely nothing when you put a baffled muffler on the end.


on the contrary, the M3 exhaust piping is about a quarter of an inch wider than the stock 325 and the 328s piping but is way heavier...

25lbs more or less isnt going to affect the cars performance

i read somewhere that 100lbs=.10

every 100lbs equals a tenth of a second more or less on your 1/4 mile

But that's not what I'm talking about. I'm talking about adding weight to an already bloated vehicle. People try to take weight away, not add it on, especially when they're adding "performance" upgrades. Putting an M3 exhaust on a 328 offers no net performance gain, but if the OP would just save up for a decent aftermarket exhaust, or get a magnaflow setup pieced together, he could actually save a nice chunk of weight.

[ducky328i]

more extreme angles of a bend? i really dont know, but i have heard its more restrictice, once again i dont know for a face. im just throwing an idea out there, seems if the pipes are much wider, to follow the same path theyd have to be bent a lil extra....:dunno

[krafty]

weight reduction is much more helpful when you are not driving in a straight line. the 25 lbs won't make a significant difference, but it does make a difference.

airflow through pipes is not just dependent on how wide the pipe is. you need to consider the muffler involvled, which in this case is not the same as the one put on the 328i as stated. plus having a variable pipe diameter before the muffler increases turbulence. in general, slapping on only a cat-back exhaust system is generally not going to net you an noticable gains.
plus i must also mention, our exhaust systems are actually pretty good stock. if you are looking for horsepower increases, consider an m50 manifold for a similar price.

[mig328]

thanks guys, i wasnt looking for power gains from the m3 exhaust just better sound. Since I had a chance to pick one up cheap I thought why not. But Im still def saving for a better exhaust in the future. Stromung?

[BL4CK-OUT]

Do M3 exhaust have deep idling sound?

[Nataliator]

[quote=Mitch;8293385]Do you know how a traditional baffled muffler works? Pipe width means absolutely nothing when you put a baffled muffler on the end.
[qoute]

thats what i was getting at! Mitch FTW. To justify this, look at it this way, the m3 is a motor with more displacement than any other 3. more displacement means more combustibles mean more exhaust. more exhaust with a LESS restrictive stock muffler means emissions trouble.
An M3 muffler, i know its hard to believe even though its got chrome tips:rolleyes , is more restrictive than your stock muffler on your non M car.

edit: plus since its more restrictive, a new OEM m3 muffler will be quieter on your car than a new OEM 328 muffler.

[paniolo]

I've always heard that an m-3 muffler will marginally help a 325 and have basically no impact on 328's which had a better oem system than the 325's.

I don't believe the m3 is any more restrictive though ... m3's have less than 1% more displacement. They get their hp from breathing better on the intake side, they aren't going to take that away by restricting the exhaust.

[RamGoat]

Still don't understand what the hell you guys are talkin about with the m exhaust being more restrictive.........anyways, I personally have an m exhaust on my e36 and its what I'm currently using as we speak.....if you're looking for something louder than the stock 325/328 exhaust, the M3 exhaust isn't the one for you....since the pipes are wider and there is a difference in the muffler design, it ends up being a little quiter than the stock exhaust.........

Anyways......if you think that 25lbs makes a major difference in your cars perfornance on the everyday daily driven side, you're just stupid......lmao.......maybe I should start driving my car on an empty stomach every time I go to the track to shave some tenths of a second of my quarter mile.......

Better yet, I'm just going to stop modding my car and just go on a diet.......THAT'S WHERE THE SPEED IS.......!

[alsteel]

Ok, I'll bite...

I put an M3 muffler on my 328. It's a direct bolt up, all you will need to replace are the washers where the mate up.

IME there was absolutely no performance difference at all. I did 0-60 runs and noticed no meaningful difference. My gas mileage wasn't affected, seat of the pants acceleration was unchanged. The one thing that is different is the exhaust TONE and the vibration. M3 exhaust is a lot deeper than the stock. It's also a little louder, but not by much. Since the exhaust doesn't have the vibration dampener that is on the stock muffler, the muffler has nice slight vibration which makes the car feel somewhat sportier, for lack of a better term. It is a little heavier than stock, around 20lbs. This may make a SLIGHT difference on a track car but on the street it's not even worth mentioning. IMO the tips do enhance the apperance of the back of the car, so for me it was a positive mod.

It's worth noting that I did not expect ANY performance gains or losses. I got exactly what I wanted, a better sounding, better looking exhaust for a lot less than aftermarket. In terms of more or less restriction I really can't comment b/c I haven't seen the guts of an M3 or stock muffler.

However, the stock 328 muffler has 2 things that obviously restrict flow; a vibration dampener and a butterfly valve. The vibration dampener is on the outboard pipe of the exhaust. It's designed to induce a destructive harmonic vibration through the use of a impeller that is driven by the exhaust gas. This is placed directly in the flow of the exhaust so I can imagine that this restricts flow somewhat. On top of that the stock 328 muffler has 2 paths for exhaust: 1) the driver's side; more restrictive and reduces noise, 2) the passenger side; free flowing. A butterfly valve forces exhaust gasses at low rpms (<3000K) through side 1, this is to comply with noise regulations and is certainly restrictive. When rpms climb above 3k vaccuum opens the butterfly valve and allows exhaust out the less restrictive side. I don't know if the "free flowing" side of the muffler is less restrictive than a M3 exhaust or not, but when the valve is open exhaust flows out both sides of the muffler.

So there you have it, those are my experiences and observations. Not sure if this helps or not, but if you are looking for a "performance" exhaust I would look elsewhere.

[Nataliator]

I don't believe the m3 is any more restrictive though ... m3's have less than 1% more displacement. They get their hp from breathing better on the intake side, they aren't going to take that away by restricting the exhaust.

2.8 liter vs 3.0 or 3.2 liter is not 1% more displacement. if its a 3.0 its 7% more and if its the 3.2 its close to 15% more. If its a 2.5, just the s50 has 20% more displacement