Silencer Ring - don't remove it?

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When I first saw the inlet to the turbo, I was expecting to see something restricting the airflow to the turbo inlet.

Instead, what I saw was an insert, held in by a C clip, that neatly helps funnel the air from a larger diameter turbo inlet to a smaller diameter inlet leading to the turbo fan blades.

After removing the c clip & the silencer ring, I noticed 3 deep recesses in the turbo housing. These are no doubt casting recesses that when exposed, cause the high pitched whine by disturbing the airflow being drawn into the turbo by the Monica effect.

Granted, removing the ring causes more noise, which I really like, but it causes turbulence in front of the turbo, which hampers airflow!

For those who played with airflow going into carbs saw the best results by making sure the airflow is 'clean' & undisturbed as best as possible by funneling or velocity stacks. The silencer ring appears to be accomplishing just that by NOT letting the air get disturbed by the indentations in the casting.

The turbo doesn't have to work as hard doing its Monica thing if the airflow is as 'undisturbed' and therfore as free flowing as possible.

Pls weigh in.

 

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CCollar where are you? Hehe... Monica. . hehe.

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3/4 ton, 5 sp, lsd, 2wd, qcab, guages, Scotty sys. Rhino liner, Blue Box hp enhancement

 

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Check previous thread on this subject. If you check the Holset web page you will find that the "silencer baffle" is an "optional" piece of equipment installed on the turbo "at the request of the vehicle manufacturer". It's purpose is to silence the whine and what aerodynamic improvements it produces are insignificant. Think about it. If a one cent piece of tin really made a detectable performance improvement, don't you think Holset would make it a mandatory component of their product and not optional?

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'00 2500, 4x4, QC, Cummins ETC/6spd, 3. 54, Camper, Trailer, SLT, 4ABS, BD E-brake, Pullrite 20. 5K 5th hitch, Tekonsha Envoy-SX Tbrake, Flame Red/Silver, Agate

 

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Checked maximum boost on gauge with and without silencer ring and found no difference at all. I sorta like the turbo sound without the ring, so this time I left it out. As an engine builder and garage hotrodder, I agree with the airflow premise however, The turbo will only accept a limited amount of air, based on boost-throttle position-load-temp, wastegate setting, etc. An intake system that is constantly under pressure behaves differently than a non turbo one. Conversely, an exhaust system, pressure regulated by an exhaust turbocharger, behaves entirely different than a gas system or non pressurized one. Take all of your mufflers, resonators and cat convertors off and stand behind your truck and listen! My 18HP riding lawnmower is almost as loud! Intake and exhaust gases behave by a different criteria if pressurized.

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1999 Dodge Laramie SLT QC, 24V Cummins turbo diesel ISB, 2WD, auto trans, 3. 55 rear end- LSD, long bed, HD towing and camper pkg,K&N air filter, Boost and Pyro gauge combo, CD player, trip computer,electric seats, bright white paint, chrome diamond plate tool box, resonator removed, 3 1/2 in. x 24 in. Glasspack muffler, 20 in. chrome flared tip, turbo silencer ring removed, all options except leather seats, Full UHF-VHF and HF transceiver equipped (KF6GUW) "I love the smell of diesel in the morning. "
Hemet, California

 

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I tend to agree with Forrest, but I won't beat a dead horse.

My only concern is impeller longevity. More turbo noise suggests to me cavitation, and cavitation is rough on any impeller/propeller. Notice I said "noise" not "whine. " I beleive the extra sound is not the sound of more air being pulled in ("whine"), but the sound of the incoming air buffeting against the flat surfaces that are exposed w/ the baffle removed. But this is all conjecture.

Craig

 

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the differences between a gas engine (velocity stack and carb), and a turbo charged diesel, are enourmous. The turbocharged engine is basically sucking its air in. I ran one of my peterbuilts (3406 cat engine) for over 1. 3 million miles, 2 engine rebuilds, the turbo whine from those babys made our 5. 9b sound quit, and never had any turbo damage, on the second rebuild, I replaced the turbo cartrige just because of the mileage, no problems with the turbo, just couldn't bring myself to run it any more. I really don't hink we have anything to worry about taking out the ring, and heck, if holset says it's ok, they make the turbo. Mine's been in the top of my toolbox since 1/1/96.....
happy turbo whine and bombs away.....

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'95 ext cab slt, auto, 4:10, 265 stones, K&N, isspro pyro & boost gauges in full pillar mt,turbo silencer ring in top of tool box, tst #6 on desk for the weekend. BOMBs away !!

 

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I don't get it! Why not just ask the designers if it hurts to remove the baffle or not? If they answer yes, don't do it,and if they answer, no, do it! Period!!

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Bob in Sacramento
Y2K All Black 3500 ISB 4x4 4:10 LSD,Auto,QC,SLT Laramie, LB, Polished Stull Billet Grill & Fog inserts, Chrome Smitty Built Step Rails, Weatherguard 'Weekender' Ladder-rack,Rancho 9000's,Diamond Plate Tool Box, OEM U. R. Bedliner.
Fact:"The First Fords' had 'DODGE' Engines-The Last Fords' NEED THEM!"

 

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we already did(ask holset), and it doesn't !!

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'95 ext cab slt, auto, 4:10, 265 stones, K&N, isspro pyro & boost gauges in full pillar mt,turbo silencer ring in top of tool box, tst #6 on desk for the weekend. BOMBs away !!

 

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Not this again, we had confirmation from Holset that it's only to make the turbo quieter. It serves absolutely no other purpose in life, none. They did it because some Dodge owners were complaining that their turbo was too loud. Some will believe what they want to and come up with their theories but in the end, it doesn't make a difference in performance or turbo life. Please call Holset and ask them, they will tell you.

 

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Just to ease everyone's mind! On Friday at work I was diong some minor repairs to a Ford F750 with a Cummins 5. 9 6BT engine. This engine uses the same model turbo (Holset HX35W) as the Cummins in my Dodge truck. I took a look at this turbo and it doesn't have a silencer ring. It has the 3 recesses in the casting just as the one in the Dodge has after removing the ring. As others have said,I would say that it is only an added option for Dodge,to reduce the whine, and has no effect on performance or turbo life. If it would effect either I'm sure that Holset would have it installed on all of the HX35W turbos,not just the ones in the Dodge trucks.