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turbo bark

26K views 24 replies 14 participants last post by  Chevydoglly 
#1 ·
not good for turbos? something ive heard and always wondered
 
#4 ·
I beg to differ......thats how my factory turbo went :blowup. Basically what happens is your turbo is spinning at 120,000+ rpm and when it barks, it is dropping as much as 40-50,000 rpm in a split second. This can bend shafts, hence grenade your turbo.
 
#5 ·
Ya definatly not a good thing. I only had mine bark one time when I was doing a burn out and hit the brakes. :rolleyes:



 
#6 ·
The bark noise comes from airflow disturbance, blade stall that results from an excessive pressure ratio, PR. It is an enormous mechanical stress.

Part of what makes it so bad on the LLY, is the restricted compressor mouthpiece. I am testing the removal of that restriction on bark.
 
#7 ·
Don’t diesel trucks and cars bark every time you get out of it to some extent? Gas turbo cars and trucks all have one thing that diesel cars and trucks don't have throttle blades (except for new trucks that have them for emissions).

when a gas car or truck with a turbo closes its throttle, the engine goes into vacuum which sends a single via vacuum hose to the blow off valve which releases the built up turbo presser to keep it from surging back ageist the turbo and stalling it.

So if your truck dose not have throttle blades or a blow off valve then every time you’re under load and get out of the throttle (pulling a trailer up a hill and some jackass cuts you off) the pressure will surge back to the turbo to some extent. So you would think that the factory would build accordingly?

I might be wrong but I think that’s how it works.
 
#8 ·
well, my turbo is insanely loud. and even under going normal throttle conditions, letting off the throttle and even when it shifts you can hear it. im assuming at such as slow rate of air that its not doing much damage at that rate but more towards WOT and letting off could be bad.
 
#9 · (Edited)
What happens is you have all this exhaust energy driving the turbo. That in turn has the compressor wheel compressing air and sending it through the intercooler and then into the engine. When you let off the throttle quickly you no longer have the exhaust energy driving the turbo, but you have all that pressurized air on the compressor side. It is looking for the easiest way out. The easiest way out isn't to continue on to the motor, but to try and come back through the turbo. This causes the compressor wheel to slow dramatically which can hurt either the wheel or the shaft. Not a good thing:Smack
 
#10 ·
#11 ·
So would that be the chirping sound mine makes when I come out of a mud hole or doing a burn out cuz my 01 LB7 does it constantly
 
#12 ·
Yup thats it! Mine did it once when i was done with a burn out. The wheels slow fast and so does the motor causing the pressure to go back through the turbo.
 
#13 ·
what kind of damage can it do cuz my truck is actin realy sluggish on initial take off
 
#14 ·
If your truck is running a big tune and you truck pull or have a seroius load when the turbo bark happens it could explode the turbo. The minimum it could do is bend the shaft the inside the turbo as Pat@BD said.

I doubt your lack of power is caused by the turbo bark. Whens the last time you changed your fuel filter?



 
#18 · (Edited)
How is a downpipe going to fix turbo bark? Read post #9 again.

When does it do it, normal driving, towing, etc?
 
#20 ·
Is yours stock its the exact same down Pipe. Since 04.5 except u have a 9th injector in yours that its
 
#21 ·
I'm still trying figure out what's going on? You're getting some kind of noise when on the throttle?
 
#23 ·
So I am getting a loud bark and the truck shakes. It's almost like the turbo is choking and it cuts air to the engine.
Next time I drive it I'll try to post a video of my vane positioning etc with the action. I have a video now but it's filled with my kids lol.


Sig: 2015 2500 LTZ Z71 CCSB Silverado
Soy beast mode
 
#24 ·
My 05 Kodiak makes a barking noise when I come off the fuel as well. Is there a fix that anyone is aware of? And I have also developed a squeal as of late I'm thinking it is a leak on the exhaust side of the turbo, maybe that is the cause of it. Anybody???
 
#25 ·
I would like to hear a solution as well, mine barks a lot, when I let off suddenly or sometimes even when it defuels for an up shift. It sounds sick, but I don't want to buy a turbo. I was looking at turbos, either aurora 3k or cheetah advertise "reduced turbo bark".
 
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