I was reading through the archives and came across something described as "turbo bark". Sounds like it's a condition associated with rapid acceleration and then the rapid release of the fuel pedal, causing a backpressure in the compressed intake air section that is forced back out through the turbo. Is this correct or is it something else that's occuring?

Is this more of an issue with the manual trucks or with the automatics? I've got the 6 spd and have not experienced this, even though I've been in situations as described above (accelerating up a steep hill with my travel trailer, full fuel and boost condition, then shifting up a gear which requires the rapid release of the fuel pedal while engaging the clutch). Wouldn't this be a condition where it would occur?

All thoughts are welcome.

 

I have only "heard" it once on my truck, I would love more info on this.

 

TDIwyse, you have it right. It is hard to bark the turbo on a stock truck, and you do have to really jump off the accelerator very fast. In your uphill scenario, you're probably upshifting when you feel the engine "run out of breath", so it's already defueled and the boost has started to drop. The turbo is more likely to bark during a lower RPM shift than what I'm describing because the boost is higher.

 

I could bark my Dmax when doing a power brake burnout then letting off the throttle.

 

Ive barked mine once gunning through a mud hole. Trust me, you will know when you bark it. I always wondered if i was barking mine or not untill i finnaly heard it once. Dosent sound very nice for the turbo.

 

Mine barks under moderate acceleration when shifting into OD; conditions have to be right for it to happen. I don't really imagine that it can be that great on the turbo, but svc. mgr assures me it hurts nothing. When it does occur, there is a real "launch" feeling, actually kinda fun, especially if you have a pax who isn't used to the mighty CTD. I always assumed it was an automatic "thing" but I guess I don't know for sure if you could duplicate conditions with a stir-stick.

 

Same here, same result....dealer said it was normal. When accelerating uphill or flat with a load on at about 2000 RPMs, then the sudden shift into overdrive, I get a nasty bark. Truck has done it since new and I originally thought it was a tranny problem from the location I thought the noise was coming from. Your right Old School...that can't be good. It sounds nasty.

One observation though. When I removed the silencer ring the bark at OD shift stopped. With the Piers modified turbo and no silencer ring, it is back. Go figure. When heading up a steep hill, I just try to give it enough go pedal to keep it from shifting into overdrive until about 55mph. I wish I could adjust the shift points so it would shift into OD at 55 all the time.

 

This just happened to me for the first time last weekend I wasnt sure what it was----sounded like a woof woof----------I will say I was in the throttle pretty good about 28# of boost and I just put the Piers B-lite turbo on about a week or so ago. When I take it easy it doesnt do it so I called Piers today and they said I am more proned to do it now with the new turbo for a couple of reasons----more boost and faster spool-up----------they did say to ease into the throttle and to ease out of it as well. It was brought up to try and take the silencer ring out-----not as proned to do it with it out. Also I did have the AFE torque tube on and maybe that had something to do with it------more air------I know it made the truck sound funny and I took it off and put the stock stuff back on.

JIM

 

Bark Bark Bark Bark.
I get all the time if I stand on it and don't let it ease into OD. Of course it's easier with the Auto. Some people call it a chuffle, it's when the pressure is suddenly released from the Turbo

 

I sure hope that's what I am hearing. Sounds like it's from the trans. The truck kind of vibrates and jumps forward. the sound is strange, not a pop or air sound, more of a drivetrain vibration, short and fast. It onle does it going into OD and I can make it not do it sometimes. Hope it's not my OD going out.

 

I get it a lot...

Maybe I can get a vid of it...

 

I did some more searching and I am sure that's what it is. Looks like removing the turbo silence ring will stop it.

 

I still get the bark when shifting into od while accelerating with the silencer out

 

I have had this several times with my 6 speed. Usually, it occurs when pulling the heavy (18K) trailer up a long hill. If I have to downshift to a lower gear because I need more power, or to lower the EGTs, I have to be careful how I do it. If I try to downshift too fast, that is when I get the bark. If I ease off the throttle a bit, let the boost bleed off about 5 or 10 lbs before I get on the clutch, then I don't hear the bark anymore. If the hill is very steep, it can be tricky to get the RPMs back up before you loose momentum..

 

Well with an aftermarket transmission and tighter tc I can bark my sps66 anytime I want. It sounds like a BIG DOG woof woofing. I installed at BD BOV that took care of 99% of barking. You can control most of it with your right foot, but I like the BOV phssssst phssssst sound better than the woofing.