Reducing Turbo Whistle

[Shadrach]

Yep you read correct I want to REDUCE the noise my turbo makes, especially when towing. I drove over 350 km ( 200 + miles ) with my 7000 # TT in tow last week end and the noise gets annoying after a while. Anything over about 10 # of boost makes her sing. The turbo is stock. I have a stock 6. 7 box and hose on the truck with a stock FLG air filter in it. I was thinking of putting a PSM style cold air pipe on it.



Will a TAG help me? Shadrach

 

[steved]

Is your silencer ring in place?

 

[AH64ID]

Sounds like the silencer ring is missing. . Even with my ring missing and the airid MIT my stock turbo was pretty quiet.

 

[RustyJC]

Will a TAG help me?

I used one on my stock HX35W-12 with BHAF on my 2002 ETH/DEE. It cut the turbo racket when towing by probably 70%-80% and the wife's racket about the noise by 100% :-laf



Rusty

 

[Shadrach]

Sounds like the silencer ring is missing. . Even with my ring missing and the airid MIT my stock turbo was pretty quiet.

Silencer ring is still there as the turbo was rebuilt by Cummins. Shadrach

 

[AH64ID]

Interesting, much louder than I would have expected.

A TAG may help, but not sure how much.

Not trying to be rude, but did you verify the ring and not just assume its there as it was rebuilt?

Just don't run a Garrett if the stocker is too loud.

 

[Prairie Dog]

I can't even hear mine from the drivers side and it's only barely audible from the passenger side. I wonder why yours is so loud?
You say the turbo was rebuilt so the silencer ring is still there. . I don't know exactly what folks mean by "silencer ring" but there's also a plastic "muffler" kinda thing in the big rubber tube that feeds the turbo (is that the silencer ring?). Some have removed the inside of this assembly in an effort to get more noise or power. I know you'll get a lot more noise without it and if Cummins did any work on your turbo, they wouldn't have touched this part.

 

[AH64ID]

The silencer ring is a cone shaped ring held into the air inlet of the turbo by a snap-ring.

You can see the ring/snap-ring in this photo.

#ad


Prairie Dog brings up a good point, does the 6. 7 intake use the same baffle as a 5. 9?

#ad

 

[Prairie Dog]

Thanks for the clarification AH641D.

 

[steved]

I gutted the intake tube and removed the directional vanes in front of the turbo... they have little effect on noise.



Not to sound like a jerk, but are you sure the silencer ring is installed? Cummins' remans didn't come with them I understood?

 

[JHumphries]

Prairie Dog brings up a good point, does the 6. 7 intake use the same baffle as a 5. 9?

Yes the 6. 7 has a very similar noise suppression device in the intake. Removing it doesn't do much for increasing turbo noise, though.

 

[Shadrach]

It was rebuilt at the local Cummins shop and I installed it on the truck myself. Even though I have a 6. 7 air box and tube assembly it is stock as well, except I plugged off the hose that went up to the valve cover. BTW Cummins Recon exchange turbos would have the ring installed as it is the way the turbo was built originally and that's what they sell - original rebuilt parts. Shadrach

 

[AH64ID]

If your ring in installed, and you have the baffles there should be zero turbo sound!

My stock turbo with the ring missing and the baffles missing only was audible from 5-15 psi, above that the motor was louder.

 

[Shadrach]

Solved the noise problem. Even though I had retightened the hose clamps on the CAC hoses myself, after a mechanic friend took it for a drive today and "he" tightened them up I no longer have the whine when under load. Seems there was just enough of a leak to make the "boost whistle". It's nice when someone recognizes the noise for what it is. He said using the exhaust brake a lot can put stress on the boots and to check them once in a while foe cracks and loose clamps. Lesson learned. Shadrach

 

[AH64ID]

He said using the exhaust brake a lot can put stress on the boots and to check them once in a while foe cracks and loose clamps. Lesson learned. Shadrach

Can you ask him to explain that one. . There is no boost on the CAC tubes when the EB is engaged, no boost means no stress.

 

[Shadrach]

The boost drops right off then pressurizes the hose when you apply the throttle again. Pressure - no pressure - pressure - no pressure, I think is what he meant. Shadrach

 

[AH64ID]

The boost drops right off then pressurizes the hose when you apply the throttle again. Pressure - no pressure - pressure - no pressure, I think is what he meant. Shadrach

No different than without an exhaust brake. Exhaust brakes have to have the motor at zero fuel to operate, zero fuel means zero boost.

 

[Shadrach]

I have been wrong before. I'll check with him next week for clarification. Shadrach