Engine/Transmission (1998.5 - 2002) Silence Ring

[skillsaw]

I was just replacing my Vacuum cylinder for my Pac-Brake. I took off my K&N filter & tubes to my turbo, & saw the ring sitting in the little nook. I keep hearing about taking it out. Well, I searched all the posts before I dove in. I was a little nervous, as it was late at night, I was at another house, & I had to drive home tonight. (still had to do the Pac-Brake) Well, the thing popped right out. Took about 2 minutes!!



A bit of advice... . If you should so happen to pop the ring out, I would suggest wiping the area after it's out with a cloth with oil on it. I noticed that a little bit of aluminum shavings came from the removal. I happened to have the oil out for the K&N & it clicked to make sure all metal was out before starting it up. The oil will help the shavings stick to the cloth.



Well, I'll be starting her up in a few... . Can't wait!!



-Erik

 

[lil red cummins]

took my silencer ring out last night - drove around the block - didnt like what i heard which was a higher amount of varied frequencies of whine. put the ring back in 5 minutes later. love it just the way it is!!!



after looking at what the ring covers, it seem illogical to remove it, because it funnels the air into the turbo opening with a smooth edge. otherwise the air may be turbulent going in against a sharp edge.



seems to me to have better flow characteristics with it in. isnt that what everybody was so excited about with the TAG????



jim

 

[Forrest Nearing]

it also looks like it limits the amount of air flow past the compressor wheel when you let off the throttle... just looking at it, it looks like less wear/tear on the turbo w/o the silencer...



also, the compressor wheel grabs air from the slot during boost/power production... the silencer looks like it would prevent that...



Holset calls it their "MWE" (Map Width Enhancement) slot... which tells me that it's designed to enhance compressor efficiency...



everyone says there's no performance difference with or without, but just looking at it, it seems that it would perform better without...



Forrest

 

[Forrest Nearing]

Originally posted by Dl5treez

The only Holset application with the ring is the Dodge truck. Take that FWIW.

yeah, that's kinda how I see it... if it was such a great setup, why wouldn't they design all their compressor housings like that?



Forrest

 

[lil red cummins]

also, the compressor wheel grabs air from the slot during boost/power production... the silencer looks like it would prevent that...

what slot????. while i havent looked at the area that the silencer ring covers with a mirror, i dont see any holes or slots in the casting behind the silencer ring.



the silencer ring does NOT cover the intake area of the turbo. in fact the ring is about . 1" larger dia. than the turbine intake area.



i would like to hear some concrete facts from an actual airflow engineer. i am just not convinced that there is an advantage by removing it, but i am willing to learn based on engineering facts rather than SOP.



by the way, i looked at the intake area yesterday, on a cummins in an F700 that i work on regularly. the intake area has a smooth funnel cast into the housing.



jim

 

[skillsaw]

Well, my ride home last night was a blast... . My Pac-Brake's been down for about 2 months now, I have the new Vacuum Cannister attached & removed the ring... ... Last night might have been the most inefficient drive of my truck's life!! & it sounded great...



I'll report back in a few weeks. I do a lot of driving



-Erik

 

[skillsaw]

no change in performance... just sound

 

[Forrest Nearing]

Originally posted by lil red cummins

what slot????. while i havent looked at the area that the silencer ring covers with a mirror, i dont see any holes or slots in the casting behind the silencer ring.

they're there... Holset designed the compressor housings like that for a reason. you can see them without a mirror... just look down in the throat by the compressor wheel. you can see the slot.



Forrest

 

[skillsaw]

Is this sound increase from the turbulence added by the ring being removed?

 

[Forrest Nearing]

I think it's from the sides of the blades on the compressor wheel contacting the air in the slots...

 

[skillsaw]

The casting just inside of the ring was left pretty rough. As is the casting just before the fan blades... . I didn't do that over time did I? Is that from factory? I figured the ring was to smooth the air flow over the bad factory castings & I disturbed that flow... It's great to hear when the power kicks in though!!

 

[Forrest Nearing]

the castings are fairly rough where not machined. the ring is purely for sound supression

 

[GAmes]

I had mine out for awhile, but after towing my 13,000 pound trailer awhile I was averaging about 1 less mile per gallon than with it in. That is about an 8% decrease, not worth the extra turbo whine to me. I put mine back in. Then I installed an AFE filter and got the whine back and it didn't decrease my mileage at all.

 

[Big P]

I just pulled my ring today. Should have done it years ago. Now the truck sounds really obnoxious.

 

[skillsaw]

I second that... I see absolutely no difference. Other than that nice whine!!!!