I noticed a flutter sound when towing my fiver on grade during
a sudden decel...I take it the turbo is venting off pressure.
I looked under truck and located what looks to be the wastegate.
Is this normal?

It does it when not towing too on a steep incline and suddenly
backing off the gas pedal.

Normal?

Can a aftermarket blow off valve be added to eliminate this
awful sound? Anyone have a aftermarket blow off with the
nice whissle sound?

Anyway kind of a weird sound. Everyone in the truck said
"what the heck was that"

 

The noise you hear is known as barking. It's caused by the high boost pressure escaping through the compressor. It's supposed to be harmful if you do it a lot. A search on "barking" or "turbo bark" will turn up threads similar to this one.

 

any chance its just exhaust back pressure, i hear it when i take foot out of heavy acceleration and mine is definately exhaust. just thinking outloud.

tim

 

As stated in one of the other post about barking the Turbo. You may want to take a look at your air filter. It may need replacing or cleaning

 

My airfilter was just cleaned before our trip. Take a look at my pictures in my gallery. I made the mod to my airbox...I have a lot
more flow into the airbox.

Dont our trucks have a waist gate to vent over pressure in this
situation?..What is the waist gate thingy I see under the truck on the turbo?

Thanks

 

The waste gate limits the amount of boost the turbo can make by bypassing exhaust around the turbine wheel. Barking isn't caused by excessive boost. When you let off the accelerator suddenly, the turbo is still trying to make boost but the engine isn't accepting it, so the compressed air pushes back through the turbo until the turbo slows down. The comment about the air filter was made because severe cases of turbo barking can crack the filter element or partially unseat it inside the box, allowing dirty air into the engine. This does not typically happen on stock trucks, the boost pressure is too low to harm the filter.

 

BD has this product to stop "Turbo Bark"!

BD Turbo Guard

 

wannadiesel
thanks for the explanation. why cant the waste gate open during
the barking situation to avoid this?

 

The excess boost is caused by the momentum of the turbo, not by too much exhaust flowing through the turbine. The wastegate doesn't bypass air, it bypasses exhaust. Opening the wastegate would have no effect.

I wouldn't lose any sleep over turbo barking, it's easy enough to avoid by easing out of the throttle instead of jumping off it. The few panic/emergency situations where you have to jump out of the gas won't hurt anything.

 

Mine has done that from day one,but I knew what it was since my 2000 with 40LBS of boost would do it often it I let off quick,I have heard it is not good for the turbo.