[brad65ford]

Hard to explain what I'm asking but how come there isn't a way to create two merging sections right after the turbos to which they come together equally then go back to the exhaust. After hearing a single turbo S55 I'm like holy hell does it sound good. Don't think we will ever achieve that sound with out merging the two turbos exits at the same time instead of mixing them in with long tubes that are attempted to be equal lengths down the line. Assuming this is how a GTR is setup as well, two equal lengths going into a split off exhaust?

[Sequence_]

Originally Posted by brad65ford

Hard to explain what I'm asking but how come there isn't a way to create two merging sections right after the turbos to which they come together equally then go back to the exhaust. After hearing a single turbo S55 I'm like holy hell does it sound good. Don't think we will ever achieve that sound with out merging the two turbos exits at the same time instead of mixing them in with long tubes that are attempted to be equal lengths down the line. Assuming this is how a GTR is setup as well, two equal lengths going into a split off exhaust?

I guess no one has spent the time to do so, there are also all 4 lambda sensors to contend with also. but it should work although tight for clearance.

The GTR by default will be equal as it is a V and not inline and god do they sound good.

[brad65ford]

Thanks for the responses, to me its really seems to be the only way to achieve better sound instead of what we are currently seeing. Seems there has been two attempts, 1 large piped -mid pipe which I had on my last M2 Comp and now these 2 long mid pipes in which one is longer than the other to make up for the shorter length down pipe. Seeing all those bends and funky curved pipes, one would think the exhaust isn't always going moving at the same velocity/speed when it gets to the end. While the AA equal mid pipe sounds the best, its still off especially at different RPM / load ranges which people with good ears have reported. would be so much better to have the DP's equal length and go into mid pipe even if it means its a bitch to install. Wishing I was a fabricator and had a mach up motor out to see if it could be achieved. While its just a guess, have a feeling this would be the next step forward in sound for the s55 if it could be created.

[atruong247]

Originally Posted by brad65ford

Thanks for the responses, to me its really seems to be the only way to achieve better sound instead of what we are currently seeing. Seems there has been two attempts, 1 large piped -mid pipe which I had on my last M2 Comp and now these 2 long mid pipes in which one is longer than the other to make up for the shorter length down pipe. Seeing all those bends and funky curved pipes, one would think the exhaust isn't always going moving at the same velocity/speed when it gets to the end. While the AA equal mid pipe sounds the best, its still off especially at different RPM / load ranges which people with good ears have reported. would be so much better to have the DP's equal length and go into mid pipe even if it means its a bitch to install. Wishing I was a fabricator and had a mach up motor out to see if it could be achieved. While its just a guess, have a feeling this would be the next step forward in sound for the s55 if it could be created.

This is actually the correct way to do equal length piping. The downpipes should have the equal length part of the exhaust. The skyline gtr's have an aftermarket downpipe option that is essentially an equal length y pipe that goes into a single exhaust pipe.

[brad65ford]

Originally Posted by atruong247

This is actually the correct way to do equal length piping. The downpipes should have the equal length part of the exhaust. The skyline gtr's have an aftermarket downpipe option that is essentially an equal length y pipe that goes into a single exhaust pipe.

I hear you. Then there is the whole single vs twin scrolls. Does the gtr have twin scrolls unlike our single?

[atruong247]

Originally Posted by brad65ford

I hear you. Then there is the whole single vs twin scrolls. Does the gtr have twin scrolls unlike our single?

Pretty sure theyre twin setup is similar to ours. monoscroll twins.

[McBobby Jr]

Originally Posted by brad65ford

Hard to explain what I'm asking but how come there isn't a way to create two merging sections right after the turbos to which they come together equally then go back to the exhaust. After hearing a single turbo S55 I'm like holy hell does it sound good. Don't think we will ever achieve that sound with out merging the two turbos exits at the same time instead of mixing them in with long tubes that are attempted to be equal lengths down the line. Assuming this is how a GTR is setup as well, two equal lengths going into a split off exhaust?

This is it right here. Surprised I haven't really seen anybody talk about this even on the Equal Length thread or at all on the F80/F82 Forum. This in my opinion would make the most sense, and would leave a lot more room for other potential exhaust setups like a single mid or just a normal twin setup after the two down pipes join and not having to worry about a squiggly exhaust pipe and fitment with some of the equal length systems on the market.

[doughboy]

The reason its not discussed on the EL forums is because it won't work like that.

You can't do it because one turbo outlet is way in front of the other. You'd need a whole load of squiggly tubing that you don't have room for in that area. That's the whole problem.

N54 had symmetrical opposing turbos so they merged together between 3&4, already equal length.

S55 has two rear facing turbos so you'd have to bring the rear turbo exhaust back towards the front then merge with front turbo exhaust all in a place where you have no room to do that.

Making up the length post- engine bay is the only way in the S55.

Two turbos will never sound like a single either..

[McBobby Jr]

For those still curious. https://www.bimmerpost.com/forums/sh...php?p=30541999

[mike@x-ph.com]

Originally Posted by McBobby Jr

For those still curious. https://www.bimmerpost.com/forums/sh...php?p=30541999

[atruong247]

Originally Posted by doughboy

The reason its not discussed on the EL forums is because it won't work like that.

You can't do it because one turbo outlet is way in front of the other. You'd need a whole load of squiggly tubing that you don't have room for in that area. That's the whole problem.

N54 had symmetrical opposing turbos so they merged together between 3&4, already equal length.

S55 has two rear facing turbos so you'd have to bring the rear turbo exhaust back towards the front then merge with front turbo exhaust all in a place where you have no room to do that.

Making up the length post- engine bay is the only way in the S55.

Two turbos will never sound like a single either..

The RB26 stock twin turbo setup also has 2 rear facing turbos and are quite far from each other. Their equal length downpipe works. It’s just, like you said, no room for the extra piping on these F8x.

[dead.pixel]

As others said, there doesn’t appear to be a way to achieve equal length with the available space. Even the existing AA single and equal length setups are a tight fit, with a lot of owners having to make adjustments after an initial fitting.

I think a lot of the equal length issues would be solved if there were secondary cats and larger resonators engineered into them. That’s what provides OEM like refinement. But that development is expensive and most buyers seemed to be obsessed with removing anything possible which would reduce flow, even if the performance impact is negligible.

[doughboy]

Originally Posted by McBobby Jr

For those still curious. https://www.bimmerpost.com/forums/sh...php?p=30541999

That's a great effort yes, but even they admit it's not EL, just part way there.

Great fabrication skills.

[McBobby Jr]

Originally Posted by doughboy

That's a great effort yes, but even they admit it's not EL, just part way there.

Great fabrication skills.

Yes, that’s why I stated “2-1 downpipes, that are almost equal length.” in my post. Better than the OEM unequal length difference, but yes not quite there. Equal length downpipes could technically be done with the downpipes fabricated for DriftWorks. They would just have to stretch out the downpipes really far, but in that case just equalize it with a midpipe. Regardless of what is done, the manifolds are still unequal so no matter the end result of whatever downpipe or midpipe combination. A single turbo kit rivals all.

[doughboy]

Agree yes, none of these are perfect, just an excercise in finding what works best...