[turnsignalslol]

I've done some research over the past couple of days trying to figure out whether a single midpipe or a dual midpipe would be louder. My car has catback exhaust with a single midpipe and my friend has a catback with a dual midpipe yet his sounds louder. If it's worth mentioning, he has a manual and I have an automatic.

I'd assume the single midpipe should be louder since the piping is massive but it doesn't seem to be the case. I originally thought it could be due to the axleback design but upon closer inspection, the valves are generally in the same area so it shouldn't really affect anything when valves are fully opened.

I've also noticed that my other friend's M4 with just a PSI midpipe (x-pipe design) sounded loud and could be heard from a good distance away.

Could it come down to the material that is used to create the exhausts? From what I know, both are constructed with 304 stainless steel but obviously quality can differ between brands but I'm very confident that both exhausts are made with good materials.

It could also be that I haven't really been outside of the car under full throttle but I also roll the windows all the way down when driving fast and my friend's car sounded way louder than mine when he did the same thing.

I'll leave the links to the exhausts here so that you guys on the forums could help me decipher what makes one louder than the other. Looking for an explanation from an engineering perspective.

My exhaust (IRL Catback) - https://irlllc.com/products/irl-g87-...42685615014046

Friend's exhaust (Milltek Catback) - https://europeanautosource.com/produ...47961399165250

[mike@x-ph.com]

The dual midpipe is louder.

The single has a deeper midrange and a rasp-free high RPM.

The single is the most popular option because it offers the cleanest sound, not the loudest.

[Info@mad-us.com]

Originally Posted by mike@x-ph.com

The dual midpipe is louder.

The single has a deeper midrange and a rasp-free high RPM.

The single is the most popular option because it offers the cleanest sound, not the loudest.

Agreed. The single with its deeper tone does give the feeling that it's not as loud. Their are DB meter apps on the phone that will give you more data.


Design, material, material thickness, muffler connection pipe angles, muffler flow rates all will change the volume and sound in general.

Aso this

''It could also be that I haven't really been outside of the car under full throttle but I also roll the windows all the way down when driving fast and my friend's car sounded way louder than mine when he did the same thing.''

[MASHCT]

I think this is one of those topics that's as beat as a dead horse. There are a BUNCH of threads on this topic with the same answer(s). Search is your friend.

[mike@x-ph.com]

Originally Posted by MASHCT

I think this is one of those topics that's as beat as a dead horse. There are a BUNCH of threads on this topic with the same answer(s). Search is your friend.

I agree, but what can you do

It's better to answer it in case it helps other that are searching for the same answer

[Info@mad-us.com]

Originally Posted by MASHCT

I think this is one of those topics that's as beat as a dead horse. There are a BUNCH of threads on this topic with the same answer(s). Search is your friend.

I answer a Single VS .... midpipe almost daily.

Google results love it though

[turnsignalslol]

Originally Posted by Info@mad-us.com

Agreed. The single with its deeper tone does give the feeling that it's not as loud. Their are DB meter apps on the phone that will give you more data.


Design, material, material thickness, muffler connection pipe angles, muffler flow rates all will change the volume and sound in general.

Aso this

''It could also be that I haven't really been outside of the car under full throttle but I also roll the windows all the way down when driving fast and my friend's car sounded way louder than mine when he did the same thing.''

Had a friend stand outside and record the car, definitely had a good amount of sound but yeah after doing some more research I guess a dual pipe setup would be louder. That's probably what I'll be going for next

[turnsignalslol]

Originally Posted by MASHCT

I think this is one of those topics that's as beat as a dead horse. There are a BUNCH of threads on this topic with the same answer(s). Search is your friend.

I searched for this for days prior to making this thread and couldn't really find anything. Search on Bimmerpost usually doesn't help me find any results so I go to google and just put "Bimmerpost" after to try to look for answers.

[AZG87]

Single is deeper. Equal length like AA is much more aggressive. Personally went for the latter but it's all personal preference.

[mike@x-ph.com]

Originally Posted by AZG87

Single is deeper. Equal length like AA is much more aggressive. Personally went for the latter but it's all personal preference.

+1

single has a cleaner tone with zero rasp

the equal length is more aggressive, with some rasp. the raspiness is not on the same level as the dual pipes, but its certainly there.

[Dave07997S]

I think the dual pipes can be more subtle like the Dinan as it keeps the secondary cats in place.

[mike@x-ph.com]

Originally Posted by Dave07997S

I think the dual pipes can be more subtle like the Dinan as it keeps the secondary cats in place.

it's a different conversation now. I was comparing the designs with everything else equal.

If one midpipe removes the secondary cats and one keeps them intact, the first one will be louder regardless of the design.

[Dave07997S]

Originally Posted by mike@x-ph.com

it's a different conversation now. I was comparing the designs with everything else equal.

If one midpipe removes the secondary cats and one keeps them intact, the first one will be louder regardless of the design.

Mike is there a single pipe that keeps the secondary cats?

[mike@x-ph.com]

Originally Posted by Dave07997S

Mike is there a single pipe that keeps the secondary cats?

not that im aware of

[Info@mad-us.com]

Originally Posted by Dave07997S

Mike is there a single pipe that keeps the secondary cats?

It's possible to make but the single pipe section would be very very short. 1-2 feet max.