Turbo Noise

[Cummin Dodge]

Sometimes when I let off the accelerator in my truck kinda quick I hear a chatter noise kinda like at the truck pull when they end there run. I had somebody else in the truck and they heard it and told me that my turbo was spinning backwards and that it is really hard on turbos. They told me my waste gate wasn't opening quickly enough. The higher the level of the programmer is the more frequent it happens. Do I need to fix the factory one or buy a new one like the one from Banks.

[ISX]

I don't have much experience with resolving this but it sounds like your friend is right on the money and after searching around a whole bunch I found something about a boost elbow fixing it since the needle valve in the elbow makes the pressure rise/drop very slow so it doesn't transfer the pressure spikes to the wastegate and cause it to slam open. There is a guy with a truck identical to mine who has less power and his does it but mine never has so I don't know what causes it, apparently not power. I know this cause I blow his doors off every time we race. Hopefully someone who knows the true cause will chime in.

[AH64ID]

It's turbo bark, which is the backflow of air thru the compressor. I am not sure the turbo spins backwords thou. The wastegate is out of the equation when you let off the throttle. What happens is the turbo is moving a lot of air and all of a sudden the drive pressure disappears, but the boost pressure doesn't. If this is coupled with a loss of rpms there is a need for the air to go somewhere and back out the compressor it goes.

[JOHNFAK]

Yup ^^^ Bad for turbos Nothing to do with programmers Controlled with your foot If its done bad enough you can push oil through the seals into the compressor housing or snap the shaft

[Cummin Dodge]

Thanks for y'all's help. Is there anything like a different waste gate, boost elbow or is it time for a better turbo.

[JOHNFAK]

Thanks for y'all's help. Is there anything like a different waste gate, boost elbow or is it time for a better turbo.

Put some air to the boost elbow and make sure the wastegate is opening. Dont think you need a new turbo - check wastegate opening first (at what PSI) and also boost leaks and any shaft play in the bearings. If you decide to upgrade from stock - look at a he351cw off a 3rd gen .... or a hybrid 60mm compressor wheel.

[KATOOM]

AH64ID is exactly right on why it happens. All that pressure has to go somewhere so it tries to go back out the way it came in. Turbos will "howl" when the pressure pushes against the compressor and manuals are more common to hear that too while shifting gears since auto's dont generally chop the throttle. The higher the boost, the louder the howl. But.....wind up the turbo too high and chop the throttle to harshly and that howl will turn into a "bark". Barking is the extreme pressure shoving its way violently back through the compressor and can actually cause the impeller shaft to stop and spin backwards. Very bad and will eventually cause damage depending on the level of boost created and how far out of the turbos map. Given your your truck year and tranny, I believe you have the HY35 which is good to about 30 psi before your out of map range and the turbo is spinning to fast, creating more heat than its doing good. If you're pushing that kinda boost or more, this is why your hearing the turbo bark. The HX35 is capable of a little more boost (35 psi) but the real difference between the two is the housing size. Most diesels dont have an intake venturi so therefor using a pop off valve or blow off valve isn't common, although guys who build big boost may install one to help give the pressure an exit. If you watch the pulling trucks, they run a spring loaded gate which shuts off the turbo intake opening upon cutting the throttle at the end of the run.The only reason your problem would be connected to the wastegate would be because the wastegate isnt opening properly and allowing you to build too much boost. But if the wastegate is working, then its not the problem. Most guys want high boost numbers since they think its cool or thats how to build HP so they J hook their wastegate.

[AH64ID]

Most guys want high boost numbers since they think its cool or thats how to build HP so they J hook their wastegate.

I get funny looks with my 400+ rwhp and 30-32 psi and great EGT's :-)

[1ngenro]

Has anybody ever heard of the boost whistle? I was driving up a hill, i pushed on the accelerator and out comes this sound like :whistle:happen to anybody else?

[dripley]

I hear it in mine when it is spooling up. I really started noticing it when I installed my Banks system.

[AH64ID]

That's different. Turbo bark only occurs when going from a WOT to zero throttle position in conjunction with a rpm drop.

[dripley]

That's different. Turbo bark only occurs when going from a WOT to zero throttle position in conjunction with a rpm drop.

Absolutely differant. That is just normal spooling. I have never heard the bark when i have let off quickly.

[KATOOM]

Has anybody ever heard of the boost whistle? I was driving up a hill, i pushed on the accelerator and out comes this sound like

happen to anybody else?

Is this a serious question?

--- Update to the previous post...

I get funny looks with my 400+ rwhp and 30-32 psi and great EGT's :-)

Why would you get funny looks? There's nothing wrong with those numbers.

[AH64ID]

Why would you get funny looks? There's nothing wrong with those numbers.

For the same reason you made the comment, many people think boost is hp. I'm quite happy running stock boost with +100 hp and better EGT's :-)

[JOHNFAK]

many people think boost is hp.

awww common

[1ngenro]

Is this a serious question?

--- Update to the previous post...

Very serious. I was checking my fuel pump to see if it would cut out on me going up-hill WOT, when all of a sudden i hear this noise that sounded like a whistle. I immediately took my foot off the peddle and it went away.

[dripley]

The whistle you are heariing is normal. It is just the turbo spooling up. Let off the throttle, the turbo quits spooling and the whistle will stop.

[KATOOM]

I wasn't trying to sound insulting by making that statement but that if someone driving a "turbo charged" vehicle hasn't ever heard their turbo whistle then maybe there's a problem with the turbo or they simply never pay attention to their vehicle's noises. Thus the reason why I asked if the question was serious. So now knowing that its a normal noise, if you're not hearing the turbo spool (or whistle) when the throttle is applied then maybe there "is" a problem. With that though, you'd experience serious lack of power.

[1ngenro]

No offense taken. I have only heard the turbo whistle twice. I have a stock filter compartment, therefore i was thinking that air was exiting the stock filter pressure gage, path of lease resistance rule. The reason i took my foot off the peddle was because during the whistle i heard a pop.

[KATOOM]

A pop? What kind of pop and when did it happen? You couldn't make it happen again or was it just a one time noise? In saying that you haven't heard the turbo before, anytime you are heavy throttled you "should" hear the turbo. But how much you hear the turbo would depend on your ability to hear higher pitched noises (which decreases as we get older) and if everything is still in stock form. If everything is still stock then hearing an uncommon loud hiss or whoosh may indicate a boost leak.