What the inside of the resonator looks like

[mr_robot]

There wasn't much foam/fiberglass over the solid pipes and if you see them, they were pretty clean no carbon. Those spots are melted packing on the tube.


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[PropellerHead]

Originally Posted by mr_robot

There wasn't much foam/fiberglass over the solid pipes and if you see them, they were pretty clean no carbon. Those spots are melted packing on the tube.

What you need to look at is the insulation that is over the solid portion. If it's black, oily air flowed across it. In fact- everywhere that is black had oily air flow. If any seam is not welded, it's not air tight or sealed.

[mr_robot]

Yes it was pitch black.

Now you got me thinking more on what to do now lol


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[wpoll]

While the construction of this resonator might well allow a very small amount of "crossover" gas flow, surely it's a very small percentage of the total exhaust gas flow and can be ignored?

Also, once the chamber became pressurised by incoming gases there would be very little flow "through" the unit.

I'm pretty sure it's made like it is because sealing it up more effectively would cost a lot more and do very little, if anything.

Just my thoughts - I'm not an expert!

[PropellerHead]

Originally Posted by wpoll

While the construction of this resonator might well allow a very small amount of "crossover" gas flow, surely it's a very small percentage of the total exhaust gas flow and can be ignored?

I think so, but it cannot be considered two distinct chambers or pipes if there is crossover. This effectively makes it an X over pipe like the X or H pipes that would replace it (with a lot less insulation- and thus more sound). Isn't that the point of the long held debate or did I miss something? (Totally possible, btw)

[mr_robot]

Poured some water, it leaks from the chambers and the flared ends.


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[wpoll]

Originally Posted by PropellerHead

I think so, but it cannot be considered two distinct chambers or pipes if there is crossover. This effectively makes it an X over pipe like the X or H pipes that would replace it (with a lot less insulation- and thus more sound). Isn't that the point of the long held debate or did I miss something? (Totally possible, btw)

From what limited knowledge I have of exhaust systems, a cross-over (X or H) pipe is intended to balance the exhaust pulses from each bank in the V8, providing a smother exhaust flow, resulting in more power (at certain RPMs - at different RPM ranges for different layouts) and better economy. In theory. Noise is also a factor - or at least the tone...

The do this, there has to be significant flow between the two pipe systems - enough to be either an alternative path for the main flow or to provide enough back-pressure to prevent flow.

From what I can see in the pictures from mr-robot, that resonator doesn't contain anywhere near enough gas flow (pathways) between either pipe system to even remotely be classed as a cross-over pipe. Sure, there will be *some* leakage between the systems, as the result of design and manufacturing methods but it'll be very small and not affect the exhaust in the way an X or H pipe would.

That's my $0.02 anyway...

[Fifty150hs]

Originally Posted by wpoll

From what limited knowledge I have of exhaust systems, a cross-over (X or H) pipe is intended to balance the exhaust pulses from each bank in the V8, providing a smother exhaust flow, resulting in more power (at certain RPMs - at different RPM ranges for different layouts) and better economy. In theory. Noise is also a factor - or at least the tone...

The do this, there has to be significant flow between the two pipe systems - enough to be either an alternative path for the main flow or to provide enough back-pressure to prevent flow.

From what I can see in the pictures from mr-robot, that resonator doesn't contain anywhere near enough gas flow (pathways) between either pipe system to even remotely be classed as a cross-over pipe. Sure, there will be *some* leakage between the systems, as the result of design and manufacturing methods but it'll be very small and not affect the exhaust in the way an X or H pipe would.

That's my $0.02 anyway...

[PropellerHead]

Originally Posted by Fifty150hs

I completely disagree.

The pressure of the system sealed up simply *must* allow the gasses to comingle and the evidence shows it does. If large water molecules will flow through, gassy air will as well. That air carries with it sound from the exhaust.

The unwelded center ovals through which the pipes are joined are there for support of the unwelded connections- not to seal any distinct chambers. We are then left with one unsealed chamber, pipes with holes in them, and a non-sealed pipe connecting them to the welds outside the open unit. The two cylinder banks are open to another. The gasses must mix and they do. They mix enough that the black soot coats the inside of the metal casing evenly across the two unsealed chambers. If the two chambers were distinct, the patterns would be unique. Welds would exist between them. There are none. Air flows. It joins the air from one bank to the other and rids us of the loppy sound we'd get otherwise.

It's a crossover. Whether we think it *looks* like enough of one or not doesn't matter. We don't know how much of an opening is needed, but we do know that one exists. It's really as simple as that, not only to my eye, but to my sense of logic.

Edit:

Provided research for support.

Besides, every V8 without a cross between the two banks will sound like lop sided ass. It's amplified in a dragster, but this is the extreme example of the resonance that joining the two banks is meant to allay.

Here's a solid link on how they work and why V8 exhausts are designed to be joined. And here's a pic also of a ~1" connection in an H pipe. Doesn't take a lot to balance the sound.

An X-Pipe or and exhaust H-Pipe are at the heart of a performance system and bolted in the center of the car. Also known as a crossover pipe, each system works by balancing the exhaust pulses from either side—or cylinder bank of a V-style engine. The result is a smooth exhaust flow and a more efficient engine. But what’s the difference between the two?

Here is a video of a straight pipe without any x over or H pipe. Note the loppies. This is what you hear bc the cylinder banks fire at times other than one another, send that sound straight out only their own side, and your ears are left looking for balance. You can almost visualize the cylinders moving up and down with the separate sounds:

https://www.youtube.com/watch?v=b6-zwK5th-4 Check at 1:37 for the same car with X Over pipes. It reveals a lot.

Also, they make clear that the smaller the openings between the two banks, the more low end performance will be gained. This is very good insight along with the small openings shown in the pics of the OE unit. We can infer that the smaller openings move less air and provide more back pressure which increases low end torque. This off-the-line grunt exactly what sells BMWs- especially a giant SAV, so the smaller openings make good 0-60 sense.

An H-Pipe is also shaped like its namesake and relies on exhaust expansion to balance the cylinder banks. A small section of tubing in between the main pipes provides an area for gases to expand into during exhaust pulses. Only a small amount of exhaust flows from one stream to the other as both sides push back and forth in the center section.

It also meshes well many folks experience of losing lower end grunt but seeing a happier rev up top. It never did make sense to me before, but now that I see it and pair the E53 experience with that of my E39 540, it's very clear.

[mr_robot]

I will add the water leaked very easily. I used a 20oz cup and could pour it all without over flowing.

This is surely an engineered resonator not just muffle sound but provide something they wanted to achieve.


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