I have just noticed that when I accelerate and get boost built up and then do a quick release of the skinny pedal there is a pressure release sound much like when an air valve is opened up. This sound goes away very quickly and does not happen again until boost pressure is built up. Any info on what may be causing this issue will be greatly appreciated.

 

Sounds like you are barking the turbo. Don't do that.

 

That is your turbo. The lines from your compressor to your intake have 15-20 psi in them, and then you let off the skinny pedal, so this air goes backwards, causing the turbo to slow down rapidly, or spin backwards. --I think. I don't know if 20 psi is enough to make the turbo spool backwards or not. My truck did the same thing too though. I would step on it in gear, and let off fast when I shifted just because it sounded cool. lol my hx-35 doesn't do that though. Is that because of their map slots?

 

Ooops. I won't do this anymore. Thanks guys.

 

Solution - get a GDS 60mm comp. wheel kit for your H1c,,, or put an hx35 on it. Or wh1c.

^^ they all have MAP slots in the comp. housing to prevent barkage.

I'm surprised you can bark your stock turbo with no fuel modifcations

 

Mine sounds like a pack of hounds that have treed a bear. I know it's not good, but if I brake it then the wife will have to let me buy a new one!
Justin

 

I cannot hear mine bark, I must have a Malamute

 

This just started happening after I did the Star Wheel adjustment, 90 degree fuel pin rotation and throttle linkage. When I did the Star Wheel I was only able to get 4 clicks before it seemed to bottom out. i did notice that there were some reference marks on the Star Wheel and housing area. When this so called "Barking" happens there is less than 10lbs of boost. Could I have done something wrong when making the Star Wheel adjustment? Is the fact that it's bottomed out an issue? This pressure release sound was not there before.

 

That star wheel insreases the ammount of fuel your engine gets at low boost pressures and if you have it turned all of the way down like most of us do, it is fine.but your fuel mods are giveing your engine more fuel to burn wich is increaseing the ammount of exhaust spinning through the turbo and increaceing the total ammount of boost pressure your turbo will produce. when you take your foot out of it very rapidly you are giveing the engine much less fuel and it is slowing the turbo down very rapidly because of the lack of exhaust gases to propell it, wich creates the awsome sound that makes powerstroke drivers around you pee their pants!!. this is known as "barking the turbo" this process can lead to shaft breakage in the turbo and an empty wallet!!

thats the best i can explane it and im just a kid so if anyone sees any problems with it please just correct me because im not always right and i like to learn too

 

yeah i remember when my h1c did that a few times when i had it topped out and then let off, I don't remember my hy35 doin it though.

 

Also, remember it may not be turbo bark, with straight pipe, thats just how it sounds when the turbo spools back down.

We need you to describe the acctual sound, a turbo bark is not just one good bellow. Its a series of almost little screetch's. Turbo bark is very distinct, there really is no mistaking it. Look around on Youtube at some pulling videos and see if you can find one similar to how yours sounds.

 

I was about to say that.

Our 91 with light afc mods, if you rev it up in Park and let off it will make a cool noise.

 

mine does the same with my straight 4". it makes more of a low pitched whistle. a bark is pretty noticeable.

 

Barks literally sound like a bark -"woof"

The "Pshhhoooooo" sound is normal turbine spool down.

 

I've heard turbos that sound like a pack of badgers in a den or a squirrel with his tail stuck in the compressor wheel.