Silencer Ring.....or is it?

[2broke2smoke]

cupcake !!!



ALLRIGHT ... you sound like my kinda guy !!!



now back to the topic ... i still would like to see something more than opinion on this topic ...



after searching previous posts it appears that no one on this entire site has ever contacted cummins / holset to ask the folks who designed it?



surely if folks on here can get tours in the plant then someone ought to be able to contact the engineers who design them

 

[BigGunZ]

So you went from stock, to a smooth tube with TAG, (without the white vanes), and played with this setup with and without the "silencer ring" in place?
Assuming that is correct, did you notice differences, such as spoolup, from the factory to aftermarket setup?
Did you run the factory setup without the SR?
Try the TAG with the factory tubes?

I started stock. My first mod was guages. Only thing I noticed was turbo lag. I came from a banks turbo'd 7. 3 which spooled instantly, likely because it wasn't intercooled (less airspace to pressurize). I added a TAG with smooth tube and noticed that the turbo spooled faster in the sense that the turbo lag had been reduced. Let me state that... the TAG is no magic bullet. It's a flow straightener pure and simple. What it accomplishes, is providing laminar flow to the turbo compressor wheel. Laminar flow reduces the "load" on the wheel, and allows it to spool faster. Is the TAG the best way of acomplishing this? Absolutely not!!! I'm saying that because I think that some are getting the impression that I am pro-TAG just because I have one... NOT!!! I run a TAG because it's the only flow straightener available through the aftermarket right now for those with aftermarket plumbing. Personally, I believe that the honeycomb used in the TAG doesn't need to be so small, and I'd bet that a larger honeycomb would provide the same benefit with less restriction.

I believe that the "silencer ring" does in fact reduce noise in an otherwise factory intake. It reduces noise because it helps flow. Anything that helps flow is going to affect noise but that doesn't necessarily mean that it was incorporated for that reason. I never ran a ring-less turbo with the factory intake plumbing and I believe completely that removing it makes the turbo louder (unless you have a late model TAG with a velocity cone)... I also believe that a velocity stack, convergent duct, inlet guide vanes, TAG's (or whatever you like to call them), in the compressor inlet improves compressor performance first and foremost... noise reduction is a byproduct.

 

[BigGunZ]

cupcake !!!

ALLRIGHT ... you sound like my kinda guy !!!

Now that is funny:-laf :-laf

Peace bro.

 

[BigGunZ]

i still would like to see something more than opinion on this topic ... after searching previous posts it appears that no one on this entire site has ever contacted cummins / holset to ask the folks who designed it?

What made me to start thinking all "funny" about this topic was propeller design.
Props, wheels, vanes, fans, and yes... even thingys, have to deal with a few simple facts of life in motion. Two things in particular sparked my interest...

ATM or aerodynamic twisting motion... Essentially, a spinning blade is trying to "scoop air". This scooping motion tends to create a force on the blades that tries to turn them "into the wind" . Kinda like when you stuck your hand out the car window when you were a kid... ... ..... if you allowed your body to go completely limp, your hand would have a tendency to assume a position where it would “scoop air the easiest”.

While that's real cute and all, CTM or centrifugal twisting moment, is the party crasher. Essentially... ..... A wheel spinning at high speed... and when I say high speed I mean freakin' cruisin like 15 to 30k RPM, like a modern TC does... . the blades, because of centrifugal force, try to "grow" longer. This tendency to "grow" also imparts a force on the blades that tend to drive the blades flat. Since flat blades can spin easier, with less resistance, it's their nature to increase their speed. Since turbo speed needs to be controlled electronically to a knats wee-wee... you can easily see the need to control this phenomenon. What makes CTM so crucial in this picture is that it’s 20 times stronger than ATM.

To more simply illustrate what I’m getting at, look at the 04. 5 Dodge service manual on page 1540 (it’s on-line). Notice the check for ... ”Impeller rubbing condition”. It’s a required check because debris sometimes passes between the wheel and housing AND the blades do in fact stretch in normal service due to CTM. (far more likely than the damage a grain of sand in the gap could cause)

Also look at the language calling for “crack checks”. These checks exist solely because of the forces I’ve described earlier... they cause them.

So what does this have to do with this thread, or my claim that the “ring” is there for another reason? ... Basically, these forces can also be controlled by forcing the air charge to “hit” the wheel in a certain way, at a certain pressure, and a certain velocity, to avoid having a turbo that grenades every time it has to breathe hard. This one design consideration outweighs noise reduction by 1000 times. I’ve watched turbos similar in size and performance to the Holset, explode radially (outwards from the plane of rotation). The shrapnel had enough kinetic energy 20 yards away to penetrate the aluminum skin of the aircraft sitting next to it.

The cause?

An aircraft handler walked too close to an air multiplier (turbocharger) and the hood on his foul weather gear disrupted (for a microsecond) the airflow at the compressor inlet. BOOM!!!!

If that’s a silencer, why make it in the shape of a cone or convergent duct, when some cheap plastic Asian crap stuffed with foam acting like a muffler could perform the same task?

I ask these questions... ..... I can't help it. #ad

 

[JVolpe]

Well I must be losing turbo efficiency and spool up because my II SPS66 did not have a silencer ring and the AFE Stage II doesn't have any baffles to direct the air flow correctly, darn.

 

[Pourinthecoal]

Gunz, I accept some of your THEORY, however you are not keeping all engineering principals in check when challenging everyone that has disagreed with you. I am one of these people. Yes I am impressed that you work on jet engines, thats fine, but you aren't the only educated person on these forums. My disclaimer is I am NOT a professional engineer, however have a masters degree and have taken numerous engineering classes during my post-secondary career. It appears quite basic of why the silencer ring nets no seat-of-the-pants gains.



You are under the assumption that Dodge/Cummins has engineered this intake for a reason other than to quiet down the turbo, the SL, the white vanes, however you yourself have changes the alignment of your vanes, therefore there must be some room of error in there in Dodge's judgement and engineering?



Essentially, the intake guides are there for air flow management, as you have said to make the air available more consistent. I agree with you on this (common TAG principals). However, you are assuming that removing the silencer ring has caused more drag due to the "wall" created that was once streamlined into the turbo by the SR (the intersection of the intake tube and the turbo). Yes, this is true IF the air is PUSHED or forced into the turbo. However, it really doesn't matter when the turbo is SUCKING air into it (which is what I assume a turbo is - an air pump?). It really doesn't matter AT the turbo one way or another, the air is already sucked in to the engine by the time those dynamics take place. That is why the silencer ring does not have any difference in performance whether its on or off. It is there ONLY for volume purposes. The tube vanes or the TAG change the intake air dynamics BEFORE it reaches the turbo (this is good), however by the time it gets there it doesn't really matter much. I do concede however that it probably has some small degree of better aerodynamics, however its too small to really care about.



This can be compared to sucking through a straw, or sucking through a Slurpee(TM!) straw. It doesnt make any difference. Making the straw bigger IS the difference, that is why bigger intakes are available!



It really doesnt matter to me about this subject anyway, as it makes no noticeable gains stock or modified. This thread is too long for such a minor subject. I DO however enjoy the extra whistle. I wonder why its called a silencer ring?!

 

[BigGunZ]

Well I must be losing turbo efficiency and spool up because my II SPS66 did not have a silencer ring and the AFE Stage II doesn't have any baffles to direct the air flow correctly, darn.

If you are, would you notice? Would anyone? If you could notice or measure this efficiency, or lack thereof, would the information be profitable? Do the issues I raise not make a difference because I'm applying them to the lowly Diesel? Is losing 5 percent of the "below the curve" power acceptable on an engine cranking out 600 to 1000 lb/ft of TQ? I ask these questions because I'm not sure of the answers. I almost get the impression that some of you guys are taking offense for some reason and you shouldn't be.

I like fast things. Even moreso I like fast things that always start... always run... never fail.

It's amazing that some people will spend 5k on a set of wheels that accomplish nothing, but will raise the "snake oil flag", over a 100 dollar part or free information.

 

[JVolpe]

Well I do enjoy a spirited thread now and again and the topic at least is meaningful to a lot of members with any turbo or intake tube mods. I would think the percentage of loss(if any) would be minimal, but probably measureable if it effects drive pressure. Of course on the Drag Strip it might mean the difference between 12. 000 and 11. 999 and that is enough to worry about.

 

[NHays]

All things aside

People, The turbo silencer ring was engineered to do just that, make things a little quieter. Back in the nineties in the first and second generations were in production, Crysler requested Cummins to make the turbocharger quieter because people were complaining that the cab noise was too high. So the turbo silencer ring was put into effect. There are no performance gains or losses what so ever from the ring, it just takes the harsh ringing away from the compressor wheel cutting the air. Now with the newer engines, the intake system has been redesigned and the plastic parts "silence" the turbo down a little bit so the ring would have little or no effect.

 

[BigGunZ]

Gunz, I accept some of your THEORY, however you are not keeping all engineering principals in check when challenging everyone that has disagreed with you. I am one of these people. Yes I am impressed that you work on jet engines, thats fine, but you aren't the only educated person on these forums. My disclaimer is I am NOT a professional engineer, however have a masters degree and have taken numerous engineering classes during my post-secondary career. It appears quite basic of why the silencer ring nets no seat-of-the-pants gains. ?

I think you may be reading a bit more into what I have said, but I appreciate you sentiments. I'm not arguing the fact that the silencer doesn't net any SOTP gains.

You are under the assumption that Dodge/Cummins has engineered this intake for a reason other than to quiet down the turbo, the SL, the white vanes, however you yourself have changes the alignment of your vanes, therefore there must be some room of error in there in Dodge's judgement and engineering?

Yes, I did maybe give that appearance but it was inadvertant... . it's highly possible that Dodge was thinking noise control and in the process... did something good for the turbo. However, you can't design a turbo without considering longevity, especially since you've offered up your corporate wallet as collateral in the form of warranty.

However, you are assuming that removing the silencer ring has caused more drag due to the "wall" created

I don't feel that it's an assumption. I think that the rings convergent design is beneficial to the turbo compressors' performance and I base that solely on physics. Removing the ring, you'll see a space that is opened up. A space between the outer and inner housing. Do you know what that space does? (I'm asking because I'm not sure myself) It appears to be just a hollow space in the casting.



BTW... I'm a highschool dropout with no degree and I'm not trying to "appear" educated. I just want to make sense of a few thing that make no sense.

 

[JHardwick]

After machining turbo faces for a few years for Garrett, I'd have to agree that the silencer ring is just that, a silencer ring.



We lost the whole deal because of supply, but we were one of the first "lost foam"/"machine shops" in the country ... ... ..... this was back in the late 80's to early 90's ... ... ... ... . I've tabulated many cylinders, but never added a stamped steel ring afterwards for performance!

 

[hasselbach]

As I recall cupcake

I think TIM has come back to haunt us

:-laf :-laf :-laf :-laf



In any event, I asked turbo wizzard gale banks about this when i saw him at the SEMA show, and he said it only was to eliminate any turbo whistle. It has nothing to do with power at all according to him. Looking at it you might think it would help, but again, he said it doesn't.



I removed my baffles too. I think they keep the air from vortexing and making more high pitched noise. They look like they might help in the flow department by keeping the air from stacking up in the elbow, but I sold my flow bench so I can run some numbers.



Anyone have a flow bench handy? This would be a good test to do.



I didn't graduate high school either, and I have a fairly low IQ, but I did stay at a Holiday Inn last night.

 

[JHardwick]

I didn't graduate high school either, and I have a fairly low IQ, but I did stay at a Holiday Inn last night.

Yeah, I stayed at Holiday Inn too, but ... .....



The more I think of it, I've sat for hours loading "X-Y" coordinates on these tabulated cylinders just to make a 5 minute program to machine this surface ... ... ... ... . a surface machined with diamond and the casting rejected if the porosity was too great ... ... ..... a steel stamping may silence the turbo, but it aint gonna flow better!

 

[BHolm]

After I removed the SR from my '06 I didn't notice any increase in turbo noise. Seems like the guys that have are pre-plastic vanes trucks. Maybe it is time to gut that tube as well :-laf

 

[99Supercab]

I didn`t notice much differance on mine either until I added an intake. Then it was very noticable.

 

[Pourinthecoal]

Does anyone understand WHY the silencer ring makes no difference in flow into the turbo (I am terrible in trying to describe what I am thinking... ).



Please agree or disagree with me on this... prove me wrong if you can, I am applying common physics to something that may be more complex than I am seeing it:



Gunz: that gap that is the result of removing the SR has the abiity to restrict flow, however that is in the instance of the air being PUSHED into the turbo (which by all acounts does not happen, no matter what the "Ram Air" manufacturers what us to think). This gap is like a wall against the aerodynamics, think the tailgate of your pickup. In effect, the air is not pushed into the turbo unless we are going REALLY fast and the turbo has no spool, however when we are using the turbo (making it sing so to speak, producing power) it is PULLING air into itself, a volume smaller than the intake tube, therefore the wall does'nt have an significant effects on the air entering the turbo. Heck, I'm almost convinced that even if the air was pushed into the turbo it would have minimal effects, as the trapped air in that "wall" or "gap" created would simply BE trapped and make an aerodynamic "ramp" int the cylinder by the trapped air.



Keep in mind, this is all in theory of what I've learned in my university physics class (about 5 years ago), so I have no physical readings or evidence to back it up. So if anyone else here an either support this theory or disprove, you're more than welcome! The real world results always put theory back in its place in the end...

 

[hasselbach]

Does anyone understand WHY the silencer ring makes no difference in flow into the turbo (I am terrible in trying to describe what I am thinking... ).



Please agree or disagree with me on this... prove me wrong if you can, I am applying common physics to something that may be more complex than I am seeing it:



Gunz: that gap that is the result of removing the SR has the abiity to restrict flow, however that is in the instance of the air being PUSHED into the turbo (which by all acounts does not happen, no matter what the "Ram Air" manufacturers what us to think). This gap is like a wall against the aerodynamics, think the tailgate of your pickup. In effect, the air is not pushed into the turbo unless we are going REALLY fast and the turbo has no spool, however when we are using the turbo (making it sing so to speak, producing power) it is PULLING air into itself, a volume smaller than the intake tube, therefore the wall does'nt have an significant effects on the air entering the turbo. Heck, I'm almost convinced that even if the air was pushed into the turbo it would have minimal effects, as the trapped air in that "wall" or "gap" created would simply BE trapped and make an aerodynamic "ramp" int the cylinder by the trapped air.



Keep in mind, this is all in theory of what I've learned in my university physics class (about 5 years ago), so I have no physical readings or evidence to back it up. So if anyone else here an either support this theory or disprove, you're more than welcome! The real world results always put theory back in its place in the end...

huh? air is not pushed in. You can't push air. Is that what they taught you in university physics?

 

[BigGunZ]

huh? air is not pushed in. You can't push air. Is that what they taught you in university physics?

I think he's saying that air is not pushed in to the intake plumbing... pre-turbo.

 

[JVolpe]

Well not physics, just my simple mind, but I think he was referring to air forced into the turbo intake by truck movement through the air. Not going to be a lot of pressure that way without true induction air intake system and still not great pressure.



Dam he beat me to it :{

 

[BigGunZ]

Before the silencer ring was introduced...

Does anyone know what boost those earlier turbos were running and what the spool speed was? Also, when the SR was introduced, were there any other changes to the turbosuch as increased boost, redesigned blades, or increased spool speed?