What the heckeroni is a turbo bark?

[jmccart]

Like it says. I am investigating adding a quadzilla boost fooler with my Superchip tuner while on tow mode. I read to watch out for this?



Thanx all.

 

[HOBrian]

If you are on the go pedal hard and let up real fast, the turbo does have time to slow down causing a lot of back pressure between the motor and the turbo. This will cause air to try and flow out of the turbo causing it to "bark"

 

[jmccart]

If I have never heard this does that mean it has never happened?

Thanx.

 

[HOBrian]

I am pretty sure you would know it if you heard it. I did it once and it sound like a big wwwwoooooooooffffffff.

 

[GOlsen]

From dodgeram.org:

When the engine is loaded, very high turbine speeds are required for the turbo charger to provide intake manifold boost. When the fuel is suddenly cut off, the exhaust volume collapses and the turbocharger rapidly spins down. As the turbine looses speed, it looses it's ability to sustain the manifold pressure and compressed air rushes backward from the manifold and through the turbocharger. The momentary airflow reversal is not harmful and produces the short pSSHTT sound.

 

[Bodie]

The boost fooler will not make your turbo bark.



I could hit 50+ lbs of boost with my Smarty/EZ on the stock turbo, which is not a good thing on the stock setup.

 

[WPeschel]

https://www.turbodieselregister.com/forums/search.php?searchid=1991600 This is a link to posts that have covered this a time or two... ...

 

[JJPage]

From dodgeram.org:



When the engine is loaded, very high turbine speeds are required for the turbo charger to provide intake manifold boost. When the fuel is suddenly cut off, the exhaust volume collapses and the turbocharger rapidly spins down. As the turbine looses speed, it looses it's ability to sustain the manifold pressure and compressed air rushes backward from the manifold and through the turbocharger. The momentary airflow reversal is not harmful and produces the short pSSHTT sound.

This article from "dodgeram.org" is a good explanation until the last sentence. It is very harmful, and has caused numerous failed turbos.



Try your best not to accomplish "turbo bark".

 

[GOlsen]

This article from "dodgeram.org" is a good explanation until the last sentence. It is very harmful, and has caused numerous failed turbos.

Try your best not to accomplish "turbo bark".

Yeah, I forgot to mention that. I have seen first hand a turbo with cracked vanes from "turbo bark. " Luckily for me, it was a buddy's truck. :-laf

 

[JCasper]

After adding a Afe Stage II kit I can now here my turbo bark if I let off suddenly. I never heard it before with the stock air filter and tube.

 

[PBax]

i barked my stocker everyday for months... . no signs of problems when i took it off.

 

[ohnoitsyu]

I have a problem where I seem to accelerate and then I let off the throttle coincidentally at the same time as the transmission upshifts. That causes the turbo to bark. It did it with the stock turbo and my new SPS62. I just seem to have bad timing, damn it! #@$%! I've been trying to be mindful of this, but I still keep doing it. I guess it's from my stab-and-steer driving style.



BTW, with the stock intake, it's not very noticeable when you do it, so you may experience it and not really know it.

 

[DMcPherson]

yeah the diesel guys call it barking, but its commonly refered to as turbo surge, shich is what it is. the air is surging back to the turbo wanting to abruptly stop the turbos rotation, this is why most gas engines have a bypass valve, it lets the excess air out, thisis why you see all the turbo gas jobs making psshhhht noises when they shift.

It IS very detremental to the turbo because if it is caused to stop or slow fast enough it can shear the turbo shaft, or crack impellar blades.

 

[RustyJC]

... . abruptly stop the turbos rotation... .

There's far too much rotational inertia in the turbocharger rotor to stop or reverse from 100,000 RPM. What damages the turbo is that every flow reversal (surge cycle) unloads and then reloads the compressor impeller. This unloading and reloading of the compressor blades, shaft, etc. can lead to cyclic fatigue failures.



Rusty

 

[jmccart]

Does anyone make the safety valve for Diesels?

 

[steved]

I don't know what you guys are describing, turbo bark is a loud "chirp", not a "whoosh". "Whoosh" is the waste gate opening. If you have one bark, you will know it... the car in front of you will think you tooted the horn.



I only ever had this happen once, and that was a completely stock truck that was stuck... the automatic would cause the need for a lot of engine load/speed to spin the tires and then it would "decelerate" the engine so fast when you let off it, the turbo would bark... usually it barks it in pulses... like CHIRP. . Chirp. . chirrrppp. . and then you hear the turbo spooling down. Really common with the guys who sled pull...



I get a "whoosh" every time I shift in my 04. 5, and as I said, that's normal operation of the wastegate.



steved

 

[DMcPherson]

the wastegate only opens under pressure, the noise I think your refering to is the turbo driving against the leftover pressure in the intake, theres not enough pressure or volume to make it surge but enough to slow the impellar and make sound against the pressure. if the wastegate made noise it would happen at full throttle when the boost stabilizes

 

[DMcPherson]

Does anyone make the safety valve for Diesels?

yes BD makes a turbogaurd, its basically an electronic controlled tial blow off valve since we do not operate on enough vacuum to pull open a standard type of BOV.

and I diddnt mean that the turbo stops completely I should have said tries to abruptly stop the turbo, and most stock engines will turn the turbo to about 30-50k rpm if I remember correctly. not that that isnt slow, lol.

 

[steved]

the wastegate only opens under pressure, the noise I think your refering to is the turbo driving against the leftover pressure in the intake, theres not enough pressure or volume to make it surge but enough to slow the impellar and make sound against the pressure. if the wastegate made noise it would happen at full throttle when the boost stabilizes

Exactly... mine does it at every shift (or right before), sounds like someone squeezing a blowgun nozzle... just a short burst.



steved

 

[RustyJC]

OK, here's the engineering definition/discussion of centrifugal compressor surge:

Surge - is the point at which the compressor cannot add enough energy to overcome the system resistance[3]. This causes a rapid flow reversal (i. e. surge). As a result, high vibration, temperature increases, and rapid changes in axial thrust can occur. These occurrences can damage the rotor seals, rotor bearings, the compressor driver and cycle operation. Most turbomachines are designed to easily withstand occasional surging. However, if the turbomachine is forced to surge repeatedly for a long period of time or if the turbomachine is poorly designed, repeated surges can result in a catstrophic failure. Of particular interest, is that while turbomachines may be very durable, the cycles/processes that they are used within can be far less robust.

In the case of a turbocharger, at every shift the swallowing capacity of the engine is decreased, as is the exhaust flow. This means that the engine cannot swallow as much of the air compressed by the turbocharger's compressor, which momentarily causes pressure to spike in the intake system. At the same time, exhaust flow decreases which causes the turbocharger's turbine section to produce less drive power, thus causing the turbo rotor to slow slightly and reduce the compressor impeller's capability to maintain head across the impeller, which also drives the turbo into surge.



Rusty