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12 valve with a terrible fluttering paper bag sound from exhaust. HELP!!!

12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

12 valve with a terrible fluttering paper bag sound from exhaust. HELP!!!

  #21  
Old 02-17-2019, 03:44 PM
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Thanks for the reply cfm56, any help I can get is much appreciated. Unfortunately, mine sounds like that cold and at running temp, ALWAYS!!! Itís terrible. Yes I have 4K springs installed and to be honest I donít know what my idle is set at. Reads about 900 on the gauge but Iím pretty sure itís incorrect considering I have a Dakota digital tach adapter installed which I havenít been able to set correctly. Iím not quite sure about how to get a spot on reading of the rpm and all the google searching in the world has left me empty handed on the subject.
 
  #22  
Old 02-17-2019, 03:50 PM
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Wow man, thatís some good info there, I will check into that immediately. Iím not so much worried about anything being wrong with the truck, I just hate the exhaust tone I have. I love the sound of most 12 valves I hear and purchased one partly for that reason to only end up with a truck that sounds like ****, you know what Iím saying? Thanks again so much for your replies.
 
  #23  
Old 02-17-2019, 11:42 PM
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Ignoring the exhaust does the motor itself sound like mine? that should give you a rough idea what rpm you are at if your gauge is unreliable.

should be very fast click clacking.

Your rpm might just be low.

I mean on another note the shittier the 12 valve sounds the cooler it is in my opinion.
 
  #24  
Old 02-18-2019, 12:10 AM
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Hard to say considering I canít really hear your engine, I can only hear the exhaust. I would have to say though that itís very possible I have a low idle. I did adjust it up a little at one point but I may have still not adjusted it enough. Is there no tool out there to confirm the rpm? Iíd like to know for certain right where itís at.
 
  #25  
Old 02-18-2019, 05:07 PM
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Originally Posted by cfm56 View Post
nothings wrong with your truck, its a completely mechanical turbo diesel and its normal with no temperature or barometric pressure compensation. stop worrying and drive it.
OK but... mine doesn't sound like that. It didn't with the stock turbo, with the 60/68/14, or with the compounds. I have never heard a 12V that did sound like that. I'm not arguing your reasoning, but I'm not sure that it squares this circle either.
 
  #26  
Old 02-18-2019, 07:09 PM
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Here I made a video to help you compare

 
  #27  
Old 02-18-2019, 09:32 PM
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Originally Posted by cfm56 View Post
I did some thinking, that fluttering sound is the interaction of your exhaust gas with the turbine wheel, at cold start my truck idles at 400 rpm, exhaust flow is not great enough to accelerate the turbo to a sufficient speed where it doesn't disturb exhaust flow, but as the engine warm up the exhaust drive pressure increases speeding up the turbo to a point where it doesn't impede exhaust flow and just sounds smooth with a nice whistle.. Thats why no matter what turbo you put on there that 12 valve will do that. Mine did it with a HX35 and does it with a Cheetah.

Try jamming something in the turbo to prevent it from spinning and see if the sound is still there. No amount of drive pressure will over come a piece of metal holding it static.

TLR

nothings wrong with your truck, its a completely mechanical turbo diesel and its normal with no temperature or barometric pressure compensation. stop worrying and drive it.

Just so you dont think I'm bullshitting, I'm a jet engine mechanic, turbo's are my life, knowing how this stuff works and interacts is my job(I made an account just to type in this thread)... I thought about this for awhile before posting. The other trucks you hear are probably have a high idle, my Idle is set to 750 RPM AC off.
BS BS BS NOBODY would ever JAM something into there Turbo to keep it from turning. Do not listen to people who tell you to do something like this. They have no idea what they are talking about. If you are good at videos, JAM something into your turbo, and run the engine for awhile, and see what happens.
 
  #28  
Old 02-18-2019, 11:16 PM
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What do you think is gonna happen if you prevent the turbo from spinning? Explain.

These Michael Bay movies got everyone fucked up.
 
  #29  
Old 02-19-2019, 04:43 AM
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I assumed you were being facetious with that suggestion...
 
  #30  
Old 02-19-2019, 04:34 PM
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Originally Posted by JBearSVT View Post
I assumed you were being facetious with that suggestion...
I'm very serious.
 

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