Equal-length exhaust discussion: new S55 sounds

[kushh]

Originally Posted by jrp73

Has anyone seen any further updates from AA or Euromotive? Seems to have gone a bit quiet

AA commented on their IG today saying their EL exhaust for f80/f82 "will be very soon"

[GT_Juls]

I'll be posting my Top Gear Exhaust soon 👀. My god I love the f80 platform now.

[David@ActiveAutowerke]

Final details/photos about our M3/4 EQ mid pipe will be posted tomorrow.

[Kilabyte]

Originally Posted by David@ActiveAutowerke

Final details/photos about our M3/4 EQ mid pipe will be posted tomorrow.

Nice! I want a vid with an MPE lol.


Any thoughts about adding resonators like people mentioned?

[TopJimmy]

Originally Posted by David@ActiveAutowerke

Final details/photos about our M3/4 EQ mid pipe will be posted tomorrow.

I just hope AA calls it the "Anaconda". It looks cool!

PS: this is post #1000 on the thread!

[FlyingLow78]

Originally Posted by jhan315

I'll be posting my Top Gear Exhaust soon 👀. My god I love the f80 platform now.

Eagerly waiting to see and hear it!

[doughboy]

Originally Posted by dsmclark

Yeah I coded out cold start with bm3 too as it's just embarrassing. Don't the valves stay closed over a certain speed anyway regardless of which mode?

I wonder if the equal length miltek will work with stock rear muffler?

Milltek won't work with stock muffler, different layout.

Re valves, the valves have to open to flow max output, the main silencer is too restrictive on its own. You can hear the exhaust note change at about 4krpm in efficient as they open. (and this is documented elswhere)

I pulled the fuses to the valve drives to keep them closed to prove this, the car stays quiet to max rpm, but if you go WOT the you can feel the engine i struggling to pull high rpm due to the exhaust restriction.

They do close and open at different rev points to reduce noise as designed at factory, but at high rpm and high load they are open in all modes.

[iPod]

Hi all,

What would be the effect in performance and sound to put an H pipe right where the factory one is ? On my Milltek exhaust, pipes do not merge whatsoever and I don't think it's the right solution for performance or even resonance.



I understand I would also need an H pipe right after equalizing the length of pipes but I'm unsure if it would have the same performance benefits if it was placed closer to the engine.

I'm also staying off putting an H pipe after pipes equalized because adding the extra length did change the sound already to something I like and I wouldn't want my exhaust to sound totally different as I still want some of the S55 specific sound.

Thanks.

[doughboy]

Originally Posted by iPod

It wont without modification around the muffler. It is designed to fit the OEM secondary cats though !

Yeah I had the Milltek with OPF's replaced with hi flow cats, but it still sounded like poop so I sold it on.

But I kept the Milltek hiflow sec cats as they fit with the OE exhaust (I can go decat DPs in future but still pass MOT with secondary CATs), then I cut up the OE exhaust to fit equal length loop and H pipe.

Needs a bit more resonator capacity in there due to rasp at 4krpm-ish, but with lockdown my local exhaust shop is not doing this sort of work. Still happy with it.

If I was you ipod I'd get a H pipe welded in just behind the diff on your milltek.

[doughboy]

Originally Posted by iPod

Hi all,

What would be the effect in performance and sound to put an H pipe right where the factory one is ? On my Milltek exhaust, pipes do not merge whatsoever and I don't think it's the right solution for performance or even resonance.

I understand I would also need an H pipe right after equalizing the length of pipes but I'm unsure if it would have the same performance benefits if it was placed closer to the engine.

Thanks.

I think Milltek are relying in the gases merging inside their rear silencer (something that doen's happen in the OE rear silencer), but as said I'd still put one behind your diff, a cheap mod at any exhaust shop.

If you put a H pipe up front you'll completely ruin the EL design.

H pipe has no performance benefits in a turbo engine, it's all about sound, don't believe the hype.

It needs to be after equal length, in the easiest place right behind the diff.

[iPod]

Do you have sound clips of your car ? I'm just scared it would completely transform the sound after adding the H Pipe.

I think I'm looking for something different to everybody else. Improving the sound but still keeping some of that S55 sound character !

[ntg44]

Originally Posted by iPod

Do you have sound clips of your car ? I'm just scared it would completely transform the sound after adding the H Pipe.

I think I'm looking for something different to everybody else. Improving the sound but still keeping some of that S55 sound character !

Look at the first post of this thread. Spool Twice did this very thing, although with stock muffler.

[doughboy]

Originally Posted by ntg44

Look at the first post of this thread. Spool Twice did this very thing, although with stock muffler.

Mine's with stock muffler, same as spool_twice setup, except he has a bit more mid section resonator capacity than I do.

That's what I want to add in due course...

[doughboy]

Originally Posted by iPod

Do you have sound clips of your car ? I'm just scared it would completely transform the sound after adding the H Pipe.

I think I'm looking for something different to everybody else. Improving the sound but still keeping some of that S55 sound character !

No I don't have clips, I tried but they sound nothing like it does in real life.

Just add a H pipe - it's an easy job for a exhaust shop to cut and weld one in, if you don't like it get it taken off, but I very much doubt you will want to do that.

Prob £100 to get one put in at most.

All for a fraction of what you paid for the Milltek equal length conversion.

Mine below, the H pipe is the easy bit to add...

[TheMaster1971NL]

Originally Posted by doughboy

No I don't have clips, I tried but they sound nothing like it does in real life.

Just add a H pipe - it's an easy job for a exhaust shop to cut and weld one in, if you don't like it get it taken off, but I very much doubt you will want to do that.

Prob £100 to get one put in at most.

All for a fraction of what you paid for the Milltek equal length conversion.

Mine below, the H pipe is the easy bit to add...

[iPod]

Thanks for that mate. I think I'll have a go if I can find someone who can reverse the modification if I'm not happy with it.

Originally Posted by ntg44

Look at the first post of this thread. Spool Twice did this very thing, although with stock muffler.

I've seen quite a few videos but quality is never optimal so I can't make my mind up !

[jpsimon]

Originally Posted by jhan315

I'll be posting my Top Gear Exhaust soon 👀. My god I love the f80 platform now.

Same - it sounds amazing.

[paulina]

I recently fitted Milltek EL system on my non OPF M2C with stock downpipes and stock secondary cat. I do like the tone of the EL system but it's just bit too raspy for my taste. I have talked to Milltek about the raspiness, and apparently that is not the feedback they have heard. They reckon due to space restraints, it wouldn't be able to get 2 separate silencers on m2. Any suggestions
Here is a drive by video I shot
https://youtu.be/LpfDmNDuqXM

[GT_Juls]

Oh hi there 😍

[RevNev]

Originally Posted by jhan315

Oh hi there ��

The TopGear system isn't optimised performance wise. Twin 2.5" pipes needs to collect into a 3.5" single not 3" and the Y pipe at the end with the twin tips needs to be a reversed merge collector not a tight U bend the way that's fabricated. It appears with valves closed, the exhaust exits from the RHS and exits from the LHS with valves open so effectively, it's a twin 2.5" system reduced down to a 3" single system that's flow restrictive.

[GT_Juls]

Originally Posted by RevNev

The TopGear system isn't optimised performance wise. Twin 2.5" pipes needs to collect into a 3.5" single not 3" and the Y pipe at the end with the twin tips needs to be a reversed merge collector not a tight U bend the way that's fabricated. It appears with valves closed, the exhaust exits from the RHS and exits from the LHS with valves open so effectively, it's a twin 2.5" system reduced down to a 3" single system that's flow restrictive.

Im not shooting for the stars. I started to enjoy my own car again due to the horrendous tractor noise Ive been accustomed to. Dyno charts shows gains and I trust the professionals who built this. If you can attempt this by your calculations then by all means please improve it. I would love to hear your version as the community is eager to move on towards equal length designs.

[drgmt]

Originally Posted by RevNev

The TopGear system isn't optimised performance wise. Twin 2.5" pipes needs to collect into a 3.5" single not 3" and the Y pipe at the end with the twin tips needs to be a reversed merge collector not a tight U bend the way that's fabricated. It appears with valves closed, the exhaust exits from the RHS and exits from the LHS with valves open so effectively, it's a twin 2.5" system reduced down to a 3" single system that's flow restrictive.

There will be no dyno difference between between a stock exhaust and this TPG exhaust or any equal length system that removes secondary cats.