Equal-length exhaust discussion: new S55 sounds

[1000hp]

Originally Posted by mike@x-ph.com

I had zero drone on my M4, same with hundreds of other customers.


As I mentioned previously, I had the same issue as you at first and I even called Active Autowerke about it. After rechecking the install and adjusting the mipdipe, it went away.

I strongly recommend you re-check the install as well (mine was off by only 1 inch). Its either that or your specific setup is a bad combination with the equal length, but the equal length itself does not drone.

I checked, re-checked, adjusted, and checked again. It most definitely droned at 3000RPM for the first ~15mins of driving no matter what I did with the pipe. The pipe did not contact anything under the car at all. Beyond having the thing on the car crooked or touching something, there really isn't another way to install it. It doesn't have a ton of adjustment.
That drone disappeared completely when I deleted cold-start with zero other changes to the pipe or the installation.
I have seen a few others report the exact same issue regardless of how the pipe was installed.
It wasn't a horrible boom that made my ears bleed, so maybe we just disagree on what constitutes a drone. But it was there and it was obnoxious. I posted about it a few times before I was able to kill it with the cold start delete.

[1000hp]

Originally Posted by f82.959

LOL. It definitely sounds like a 4 banger with resonated EL mid pipes and it sounds brassy as all hell with non resonated mid pipes when paired with cat-less downpipes and valves open. I'd compare it to a CR-X with a magnaflow muffler. Sounds nice at 4500+ RPMS though...but that's about it. It also definitely didn't give me more power, it took some away in exchange for mid-range/torque. My local shop was curious since I was one of the first in the area to get the EL setup and let me throw it on the dyno after and it dropped the highest 25 and lowest of 5 whp. Ambient temps were down 15 degrees too. Pretty sure I still had a packing peanut stuck on one of them I took them off so fast.

It sounds great with the stock downpipes, though.

I would expect it to lose power over the 3.5" single. Each of those little bends in the EL adds restriction and restriction costs horsepower.
To me, it's 100% worth it for the car to not sound like a fart, which is how I would describe the stock midpipe AND the single midpipe.
If I were trying to achieve max output regardless of sound or air quality, I would do catless downpipes and single mid with some kind of aftermarket muffler.

[RugbyBro]

Well... I'm back on the stock exhaust and all I can say is it's depressing AF. It just doesn't even feel like my car anymore. Crazy how much an exhaust mod can change your whole experience/perspective on a car.

[Kilabyte]

Originally Posted by RugbyBro

Well... I'm back on the stock exhaust and all I can say is it's depressing AF. It just doesn't even feel like my car anymore. Crazy how much an exhaust mod can change your whole experience/perspective on a car.

What?! Why?

[swagon]

Originally Posted by Kilabyte

What?! Why?

Instructed my Russian cousin Niko Bellic to steal his exhaust for me

Jk

I think he put it back to stock before buying a CS but now he's back in his old car

[Slo_F80_Mike]

Originally Posted by f82.959

LOL. It definitely sounds like a 4 banger with resonated EL mid pipes and it sounds brassy as all hell with non resonated mid pipes when paired with cat-less downpipes and valves open. I'd compare it to a CR-X with a magnaflow muffler. Sounds nice at 4500+ RPMS though...but that's about it. It also definitely didn't give me more power, it took some away in exchange for mid-range/torque. My local shop was curious since I was one of the first in the area to get the EL setup and let me throw it on the dyno after and it dropped the highest 25 and lowest of 5 whp. Ambient temps were down 15 degrees too. Pretty sure I still had a packing peanut stuck on one of them I took them off so fast.

So it decreased your power that much from just running a EL setup with everything else stock??! I would assume it to go up slightly, due to taking the secondary cats out.

[1000hp]

Originally Posted by Slo_F80_Mike

So it decreased your power that much from just running a EL setup with everything else stock??! I would assume it to go up slightly, due to taking the secondary cats out.

I think he means that he lost power going from 3.5" single midpipe to the EL dual-2.5" midpipe. The bends add a lot of restriction.
I felt no difference at all, personally. But I've never dyno'd the car.

[RugbyBro]

Originally Posted by Kilabyte

What?! Why?

Trying to offload the F82 for a F80 CS - had one very briefly but that one didn’t work out. The EL midpipe will be going on the CS immediately once I’m back in one

[TideMD]

Looks like a fun weekend project is about to go down...
Big thanks to Mike@x-ph for hooking me up!

[slaughter.mode]

Originally Posted by Slo_F80_Mike

So it decreased your power that much from just running a EL setup with everything else stock??! I would assume it to go up slightly, due to taking the secondary cats out.

Sorry, it decreased it from my Single AA mid pipe. I have aftermarket turbos as well.

[Slo_F80_Mike]

Originally Posted by f82.959

Sorry, it decreased it from my Single AA mid pipe. I have aftermarket turbos as well.

Ohhh okay, that makes sense then. Probably created more back pressure. Wonder if it does increase any power on a stock setup like mine

[slaughter.mode]

Originally Posted by Slo_F80_Mike

Ohhh okay, that makes sense then. Probably created more back pressure. Wonder if it does increase any power on a stock setup like mine

Probably won't because while it may cut out the secondary cats it also adds a considerate amount of distance for the exhaust gas to travel. I mean AA even claims it only increases low - mid range torque and spool, indicating additional back pressure.

[gx5_027]

Originally Posted by kindafrosty

I was able to figure out my cold start noise issue, wanted to share in case any one else was struggling to find answers like I was. Unknown to me, the previous owner had installed the GTS Flash on the engine, which was causing the waste gates to open more and rattle during the cold start sequence. When BMW changed my spark plugs under warranty, there was a misfire immediately after due to bad plugs. Then they ran error tests, and told me my car was tuned and refused to change the bad plugs. Luckily my SA was cool, so I flashed back to stock (ZCP) with MHD, and then they changed the plugs without flagging the warranty. Cold starts now sound normal again, no more ear piercing rattles, albeit a minor buzz due to the cold start roar.

Overall, after 3000 miles with the non-res ELs, I'm very pleased as they sound even better now broken in. Still undecided on adding a resonator, as the rasp is becoming more prominent with the cold.

I'm assuming you have stock cats? What exhaust do you have? Stock as well?

Nevermind - searched and found: Non-res EL with stock downpipes and ZCP muffler

[BoxKing]

For those who installed either the Single Mid or the EL Pipes... did you/do you need to change out the gaskets from DP's > Mid, plus changing out the Exhaust Flange?

[RugbyBro]

Originally Posted by BoxKing

For those who installed either the Single Mid or the EL Pipes... did you/do you need to change out the gaskets from DP's > Mid, plus changing out the Exhaust Flange?

Just the gaskets. The hardware only should/needs to be replaced if it's rusted or no longer usable

https://www.fcpeuro.com/products/bmw...saAvfXEALw_wcB

[BoxKing]

Originally Posted by RugbyBro

Just the gaskets. The hardware only should/needs to be replaced if it's rusted or no longer usable

https://www.fcpeuro.com/products/bmw...saAvfXEALw_wcB

Thanks man, Im going to replace them no mater what, and just placed an order with the link you applied.

[McBobby Jr]

What do you guys think? I thought of this design a while back but wasn't sure if it could be done the right way. Equal Length Pipes into a Single Pipe Dual Exit. Take a look.

[Ultimateone]

Looks like it could be ridiculously loud

[Kilabyte]

Originally Posted by Ultimateone

Looks like it could be ridiculously loud

Definitely.

[ntg44]

Originally Posted by McBobby Jr

What do you guys think? I thought of this design a while back but wasn't sure if it could be done the right way. Equal Length Pipes into a Single Pipe Dual Exit. Take a look.

Will be way too raspy and farty. EL needs all the muffler it can fit. That's why it's such a challenge on this chassis.

If there's one good thing about the G80s, it's that EL is a breeze in comparison. Much more room to experiment for tonal variation.

[deli333]

guys why dont you just throw two resonators to your single mid pipe? cheap and kills drone, most of the rasp and fart.

two sound clips from my setup. mpe + resonated single mid pipe + arm catless resonated downpipes.

car sounds ace especially between 1-3k. listen the growl in 5th second in the second video

https://vocaroo.com/1sjlZ0RE0W8E
https://vocaroo.com/1mYyJxgpR8xl

[Kilabyte]

Originally Posted by deli333

guys why dont you just throw two resonators to your single mid pipe? cheap and kills drone, most of the rasp and fart.

two sound clips from my setup. mpe + resonated single mid pipe + arm catless resonated downpipes.

car sounds ace especially between 1-3k. listen the growl in 5th second in the second video

https://vocaroo.com/1sjlZ0RE0W8E
https://vocaroo.com/1mYyJxgpR8xl

This thread is about EQ exhaust bud