X pipe

[Needsnewtyres]

Evening all

Has anyone experience with fittings an x-pipe on a 5.5 v8 (R231) I want to get a little more noise whilst retaining OEM rear boxes

 

[AMGeed]

Evening all

Has anyone experience with fittings an x-pipe on a 5.5 v8 (R231) I want to get a little more noise whilst retaining OEM rear boxes

You have the 5.5 biturbo on a 2014 SL63 don't you?

I found removing the resonator and replacing with straight pipes improved the sound no end without making it unduly loud.
Instead of straight pipes, an H or X pipe can be used. My W212 E63 probably sounded the same as your SL before I had my exhaust modification.

 

[Needsnewtyres]

You have the 5.5 biturbo on a 2014 SL63 don't you?

I found removing the resonator and replacing with straight pipes improved the sound no end without making it unduly loud.
Instead of straight pipes, an H or X pipe can be used. My W212 E63 probably sounded the same as your SL before I had my exhaust modification.

Yep, 2014 5.5 bi-turbo, who did you exhaust change? Any before / after sound clips?

 

[AMGeed]

Yep, 2014 5.5 bi-turbo, who did you exhaust change? Any before / after sound clips?

I went to MSL Performance in Birmingham. Long way, but I had the car remapped, then the exhaust modified .
Two clips, before the resonator removal and one after.

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[KillerHERTZ]

You won't gain any improvement over a resonator delete with an X pipe on a Bi turbo car, kompressor engines yes.

Here's my video on the centre resonator delete:

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[Rich764089]

What about the balancing of exhaust gasses... I've read (on here maybe?) that it's better to have X or H pipe rather than straight pipe on the biturbo for this reason?

 

[Bellow]

What about the balancing of exhaust gasses... I've read (on here maybe?) that it's better to have X or H pipe rather than straight pipe on the biturbo for this reason?

This topic is oft debated on an American forum I frequent where V8s are the staple.

As it applies to NA the theory is that because two exhaust events occur in close succession and feed into the same pipe having said pipe connected to the other gives the exhaust gas a freer path via the X or H. True, assuming the turbulence at the junction doesn't in any way impede flow - unlikely.
How much of this pulsed flow exists when there's turbos in the system is debatable - inevitably their effect will be to smooth out the pulsations regulating the flow into a more even pattern and obviating the reason for an X or H.

Generally then, the pulse wave (not exhaust flow but the sound pulse) will find it's way across to the other pipe with an X or H and will mellow out the exhaust note (spreading it more evenly over the twinned outlets) compared to 'true dual' where the full effect of the V8's off-beat firing will remain and at greater intensity.

For what you want - avoid an X or H.

 

[Needsnewtyres]

I went to MSL Performance in Birmingham. Long way, but I had the car remapped, then the exhaust modified .
Two clips, before the resonator removal and one after.

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Sounds good, thanks for posting the clips

 

[Rich764089]

This topic is oft debated on an American forum I frequent where V8s are the staple.

As it applies to NA the theory is that because two exhaust events occur in close succession and feed into the same pipe having said pipe connected to the other gives the exhaust gas a freer path via the X or H. True, assuming the turbulence at the junction doesn't in any way impede flow - unlikely.
How much of this pulsed flow exists when there's turbos in the system is debatable - inevitably their effect will be to smooth out the pulsations regulating the flow into a more even pattern and obviating the reason for an X or H.

Generally then, the pulse wave (not exhaust flow but the sound pulse) will find it's way across to the other pipe with an X or H and will mellow out the exhaust note (spreading it more evenly over the twinned outlets) compared to 'true dual' where the full effect of the V8's off-beat firing will remain and at greater intensity.

For what you want - avoid an X or H.

Thanks, really helpful.

Still haven't got round to resonator delete, but hopefully soon. My my concern about straight pipe over X or H pipe was it might be sub optimal for the M157, potentially even damaging. But it sounds as though I shouldn't be concerned so straight pipes it is

 

[Bellow]

Thanks, really helpful.

Still haven't got round to resonator delete, but hopefully soon. My my concern about straight pipe over X or H pipe was it might be sub optimal for the M157, potentially even damaging. But it sounds as though I shouldn't be concerned so straight pipes it is

There's a further complication with X and H pipes that is overlooked.
When a sonic pulse travelling down a pipe encounters a discontinuity or branch it changes its behaviour. A pulse encountering an X or H will see three additional branches. It will split into four components. Two of those will remain positive and head down each pipe to the tailpipes. One will travel back toward the engine on the other pipe still positive and one will reverse polarity (become a vacuum pulse) and travel back up the pipe that the original pulse came down.
The returning (positive and negative) pulses will take a finite time (determined by the pipe lengths and the local speed of sound in the pipe) to arrive back at the engine and what they do when they encounter open exhaust valves depends on whether they are positive or negative and, where in the cycle the associated piston is - a moving target.
The 'pipe length' relevant here is the distance from the exhaust port the X or H pipe is sited and cannot be correct for all engine speeds (assuming the pulse activity can be usefully harnessed) and is likely to be a whole number multiple of the manifold runner length plus the port length. Does anyone ever check if resonator (inevitably where an X or H will be located when added to the system) positioning by the OEM is compatible with that?
It gets very complicated very quickly and is a can of worms better left unopened - IMO.

 

[jonboyE63]

Nice video KillerHertz, i've got my E63 booked in with MSL for a remap & TorqueFlow for the exhuast resonator delete mid July - i'm now really looking forward to the drive back to deepest Dorset.

 

[Rich764089]

You will LOVE the drive back.
Finally got my res delete booked to go with the MSL remap

 

[jonboyE63]

You will LOVE the drive back.
Finally got my res delete booked to go with the MSL remap

I can't bloody wait....650+BHP & a fruity exhaust....happy days..!!

 

[Phil1968]

This topic is oft debated on an American forum I frequent where V8s are the staple.

As it applies to NA the theory is that because two exhaust events occur in close succession and feed into the same pipe having said pipe connected to the other gives the exhaust gas a freer path via the X or H. True, assuming the turbulence at the junction doesn't in any way impede flow - unlikely.
How much of this pulsed flow exists when there's turbos in the system is debatable - inevitably their effect will be to smooth out the pulsations regulating the flow into a more even pattern and obviating the reason for an X or H.

Generally then, the pulse wave (not exhaust flow but the sound pulse) will find it's way across to the other pipe with an X or H and will mellow out the exhaust note (spreading it more evenly over the twinned outlets) compared to 'true dual' where the full effect of the V8's off-beat firing will remain and at greater intensity.

For what you want - avoid an X or H.

That is indeed true, when I did a resonator delete I opted for an H-pipe, but because I had to add more silencing again in the resonator's place I had no room for a crossover so had a small silencer on each pipe in it's place. The note became much more throbby & woofly, I actually much preferred it, it's the true V8 sound imo. Mercedes went to a lot of trouble to dampen out the V8 'throb' by putting a double X-pipe inside the resonator. I've noticed no difference to performance without a crossover. And needing back pressure on these engines is a myth because the stock exhaust is pretty much straight through anyway.

 

[Bellow]

That is indeed true, when I did a resonator delete I opted for an H-pipe, but because I had to add more silencing again in the resonator's place I had no room for a crossover so had a small silencer on each pipe in it's place. The note became much more throbby & woofly, I actually much preferred it, it's the true V8 sound imo. Mercedes went to a lot of trouble to dampen out the V8 'throb' by putting a double X-pipe inside the resonator. I've noticed no difference to performance without a crossover. And needing back pressure on these engines is a myth because the stock exhaust is pretty much straight through anyway.

Couldn't agree more - that 'blub blub blub blub' idle is what a V8 is about! Everyone else seems to want theirs to sound like a four cylinder running at double speed. Each to their own.

 

[Rich764089]

Well this is excellent to hear as that's exactly what I want res delete and straight pipes a week Tues

@Phil1968 intrigued to know why you needed to add more silencing again?!

 

[Phil1968]

Well this is excellent to hear as that's exactly what I want res delete and straight pipes a week Tues

@Phil1968 intrigued to know why you needed to add more silencing again?!

I had a long journey with my exhaust, I initially went for a rear muffler delete & whilst it sounded good it droned like hell in the cabin between 1600 to 2000 rpm. I then had some small sports mufflers fitted with J-pipes & that eradicated most of the drone apart from a small amount at about 1100 to 1300 rpm. It also didn't sound like a V8 should imo, so my exhaust guy said to try deleting the resonator & going for an H-pipe to get more of the old school V8 sound. That worked a bit, but the drone was still there at 1100 to 1200 rpm. So we took out the H-pipe & put a short sports muffler on each pipe in it's place & as I said previously there was no room for a crossover so it now runs two separate pipes from front to back, a true dual. To my surprise it not only eradicated all of the drone but also made the tone deeper, whilst maintaining the volume (without being obnoxious). And as a by-product it now had that lovely old school throbby V8 sound. So the V8 sound track is now always there, but it never becomes obtrusive.
Mine is a N/A engine & I think yours is a bi-turbo? Bear in mind that turbos muffle a fair bit of sound so you can probably go further with silencing deletion without getting too obnoxious.

 

[Rich764089]

Very interesting, thanks Phil. Sorry to hear it was such a long journey!
Yes, mine is a biturbo. From everything I've read, the res delete shouldn't drone. I'm quite likely to de/sports cat sometime, so think that plus the res delete should be suitably load but not overly obnoxious!!

 

[Phil1968]

Very interesting, thanks Phil. Sorry to hear it was such a long journey!
Yes, mine is a biturbo. From everything I've read, the res delete shouldn't drone. I'm quite likely to de/sports cat sometime, so think that plus the res delete should be suitably load but not overly obnoxious!!

It shouldn't drone just doing a resonator delete

 

[jonboyE63]

You will LOVE the drive back.
Finally got my res delete booked to go with the MSL remap

What are your thoughts regarding the MSL stage 1 remap....??
i've had my E63 for nearly 3 years & i've booked the remap as i think i've got use to the power....sounds trivial but i need to reignite my love affair with the car. I came very close to selling it as there's just as quick if not quicker cars out there that are way cheaper to own & run....
Hopefully the exhaust work & remap will give me another few years before finally moving on..