My truck is doing something really goofy. With an empty truck under medium to full throttle, when it shifts to 4th, the turbo makes kind of a whooshing sound and the truck loses power. It will also do it if I am on the throttle fairly hard and then let off all at once. It will do this with full power, or at stock power levels. If I am towing it is WAY worse. It sounds like a blow off valve, but don't think our trucks have one since I can't seem to locate it. Only thing I can figure is that it is dumping pressure through the wastegate. Not sure why it would start doing this all of the sudden, or what would cause it. Any ideas?

 

That's called turbo bark. Did you add any mods recently that would make it happen more often?

Don't lift suddenly while on the throttle, this is not good for the turbo.

...............Jim

 

not too much you can do if you have a slushbox when it shifts 3 to 4...

oh, and no diesels come stock with a blow off valve/bypass valve. wastegate won't make any noise until it starts to crack open [if you have open exhaust, you can hear it]

 

My 03 SO did this when the trans would shift into o/d! And it would do it early to! I hated hearing this because what is happening is all of the built up pressure that is in the intercooler and hot pipes is rushing back against the impellars in the intake side of the turbo. This is causing what everyone on here calls Turbo Bark. This will definatly shorten the life of your Turbo. This was one of the reasons that I sold mine. The only fix that I can say do is upgrade the Trans VB and put a shift kit in with new TQ Converter! This will help.

 

I see your Trans is already upgraded?????? Good Luck. The only other way that I can say to help while driving is to just plain get on it and then let off after the truck is in o/d! This is what I was having to do with the 03!

 

The last mod was adding the "hot" upgrade to the Juice. There are guys with a whole lot more power than me and I'm not seeing this to be a common problem. Even if it was "bark" from letting off the throttle, it still shouldn't do it under throttle just because the tranny shifts. How is our wastegate activated - electronic or actual pressure? I'm wondering if something could be bad.

 

It is more common than you think with an upgraded TC/Trans. As soon as I had my tc/trans done I started barking the stock turbo the same way, OD Lockups and letting off too quickly. The only real help is a Blow Off Valve. BD Performance makes one, but kind of expensive. Now that I have 500+rwhp available, the II SPS66 just barks louder and longer.

 

I have the same problem some times on my truck. I have a Banks Six Gun which came with the truck when i bought it, but it will also be coming off soon. I hate Banks stuff, it defuels for you, and all parameters are in check by my mechanical gauges.

Turbo barks every once in a Blue moon going into OD. I am usually giving her heck though.

 

That's the thing. I've had everything on for a while without this problem - except for the hot upgrade, and I can't remember if it started before or after I re-installed the Juice. I don't really see how more power would change how it acts anyway. The wastegate should still operate properly. Has anyone had to upgrade their wastegate?

 

I noticed it more after I upgraded my juice to the hot version, your adding another 50 or so HP with that upgrade. I do my own shifting so I can control it better but it will let ya know it's there if someone cuts ya off on the freeway and your on the skinny pedal good especially if your in tow.

 

It has nothing to do with the wastegate. It is turbo bark caused by the pressure coming backwards through the intercooler and back into the front of the turbo on the compressor wheel that is causing the noise. The only thing that will fix it is slower shifts or one of these http://www.bd-power.com/ram/product....boGuard&tt=ram as Ramwheelsby4 said.

Mine will start to bark in 6th pulling hard on a steep grade if I have my Juice turned on anything but level 0. That is a hair on the back of your neck standing on end experience. It starts to sound like an old steam locomotive. Too much boost for the stocker is what that amounts to combined with high altitude. I will go for a 62/14 with a turbo guard by Fall but a clutch will come first.

 

If it's doing it under load and w/o lifting the throttle you may have a boost leak thats apparent at high pressure levels...

Try testing for a leak in the post turbo plumbing...

Make sure all the clamps are tight on the rubber hoses...

 

I don't mean to arguementative, but I think you guys are "barking" up the wrong tree. WHEN I SET THE JUICE TO STOCK - IT STILL DOES IT. It never did it before, even when abusing it on level 5. I'm thinking aggie98 might be on the right track.
staarman - you say yours does it at open throttle in 6th pulling a hill. That doesn't make sense to me. The only time it should happen is if there is a sudden change that does not allow as much air to be forced into the engine - i.e. the closing of a throttle plate or a large drop in rpm all at once. If you are at WOT, there shouldn't be any resistance or reversal of air flow.

 

There was a change in fuel because my Juice was defueling. I was pulling a 9% with 8000 lbs. with the cruise on 65 MPH. My exhaust temps were climbing to 1400 and I have the juice set to defuel at 1350. When it does defuel it gets pretty agressive. I also was seeing coolant temps of 214 and my alarm was at 210 for some dumb reason. I pulled over at the top of the hill and changed that and then figured out what all the racket was.

My turbo will bark on level 0 anytime I want it to. I have a 6 speed though so I have a little more control than an auto. My truck never did it until I put the AFE on there. However, I'm not sure if it is solely due to the AFE or a combination of the silencer ring because I took that out at the same time so who knows. It started doing it on the test drive after that install. I had the been running the Juice/EZ stack before that and never had it do it.

BTW our trucks don't have throttle plates or throttles. I do know what you are saying though. Keep us posted on the progress of finding out what the cause is.