Author Topic: my K24 sounds like it has a BOV (Read 6906 times)

zukgod1 · « **Reply #15 on:** June 16, 2008, 02:27:30 pm »

Quote from: "bugnut"

I would venture to say that it is turbo bark. Not a surge. If you let off the fuel slowly then it will not bark. Also try not to shift when on full boost. I had this happen on my dodge and matter of fact any diesel will do it when cutting fuel from full boost. Turbo still wants to spin but the air has no where to go but backwards which previous post alread said.

Correct we have been wording it wrong, Surge is completely different.

Bark is the issue at hand and as I and others now have pointed, until you get a good solution just drive nicer or risk snapping the shaft.

then it will pump oil directly into your engine and you my friend have a runaway engine..

foxracer1 · « **Reply #16 on:** June 16, 2008, 07:55:21 pm »

I understand turbo bark as to be under boost and then let off quickly. The turbo is accelerating then the drive force is released quickly.

The engine is still taking the boosted air just the same as when under load since there are no throttle blades. The turbo just slows quickly and the exhaust creates a low pressure for a split second just before then after the turbine.

I've heard many diesels do it and have not heard of damage from it. I'm sure over spooling the turbo is much harder on it than barking it.

zukgod1 · « **Reply #17 on:** June 16, 2008, 08:10:46 pm »

Barked turbo results.

Snapped shaft, ground the compressor wheel to bits and filled the intercooler with oil...

Turbo bark is bad, one side is trying to go fast than the other causing the shaft to twist. Eventually it stops twisting and just breaks.

Any questions..

James8485 · « **Reply #18 on:** June 16, 2008, 09:20:17 pm »

so will all K24's that i put on my engine (1.9 TD AAZ) surge my bros 1.6 never has done it why mine. if i change or have the turbo rebult will it fix it!

OH AND WEATHER I RUN 10 PSI OR 18PSI IT STILL DOES IT, AS SOON AS I HIT MAX BOOST AND SHIFT IT MAKES THAT SOUND
I PRETTY WELL HAVE TO BABY IT WHICH IS NOT THE POINT OF INTALLING A BIGGER TURBO!! I INTALL A BIGGER TURBO FOR MORE HP.
AND I CANT USE IT!! SOMTHING DOESNT SOUND RIGHT

carrizog60 · « **Reply #19 on:** June 16, 2008, 11:42:26 pm »

cant you make a video?

foxracer1 · « **Reply #20 on:** June 17, 2008, 04:21:43 am »

The shaft breaking is from a much more severe issue. Surge is bad, bark is just the turbo slowing down. If it causes that degree of damage then factory engines with factory turbos would not do it. I can not agree that bark is as bad as you are saying it is.

zukgod1 · « **Reply #21 on:** June 17, 2008, 07:44:37 am »

Quote from: "foxracer1"

The shaft breaking is from a much more severe issue. Surge is bad, bark is just the turbo slowing down. If it causes that degree of damage then factory engines with factory turbos would not do it. I can not agree that bark is as bad as you are saying it is.

Don't know what to tell ya man.

My broken shaft is a result of turbo bark.
Bark is more than just the turbo slowing down, as I said it's the two wheels trying to spin at different speeds causing the shaft to twist, it will only twist so many times before it snaps. You wont hear the shaft twisting just the air differential.

My engine is not stock, either is my pump or injectors so my bark was a bit extreme but the result will be the same over time.

It's common knowledge in the turbo industry the k24 has a week shaft. Combine that with allot of fuel and barking it between shifts and the result is a snapped shaft.

I'm done trying to explain this issue, the information is here have a good time.

jimfoo · « **Reply #22 on:** June 17, 2008, 08:03:06 am »

How is bark different from surge? They are just two different words for the same thing, too much pressure built up for the speed of the turbo.

jtanguay · « **Reply #23 on:** June 17, 2008, 08:23:05 am »

that sucks that you can't run 18 psi... i bring my K24 up to 20 psi all the time. maybe the turbo itself is junk (or needs a rebuild)

something to think about would also be your oil pressure at idle. if you don't have enough the turbo could be starved at idle (when you let off the pedal) but be fine when accelerating. maybe get a gauge for it.

almost seems like you might have a plugged exhaust... either way something doesn't add up. how old is your air cleaner?

zukgod1 · « **Reply #24 on:** June 17, 2008, 08:37:49 am »

Double post oops

zukgod1 · « **Reply #25 on:** June 17, 2008, 08:48:23 am »

Quote from: "jimfoo"

How is bark different from surge? They are just two different words for the same thing, too much pressure built up for the speed of the turbo.

So take this with a grain of salt, I tend to get a be over excited at times and certainly do not intend to offend or be argumentative at all.

Surge is different sort of anyway, surge is while driving at a consistent speed or under slight accell and the turbo speeds up and slows down like you were pressing on the gas peddle and letting off. Usually surge is experienced by people that have changed turbos for something way larger than stock, newer turbos (non VNT) have started coming out with larger exhaust pin wheels to prevent or lessen the surging problems.
This is something the Diesel truck people i.e. Dodge, Chev, Ford have been dealing with for a while in the aftermarket arena anyway.

Bark is as mentioned already above at least in my mind anyway, I have always considered Bark a REALLY REALLY bad surge.. Thus the different definition in my mind.
The guys in sled pulling call a bark as I have described, and the road cruising guys call it surge as it's not nearly as sever.

Either way it's worded it still destroys turbos.

I'm not a turbo expert but I have experienced allot of turbo crap coming from the Cummins performance area. Building a Cummins is not much different than our little 1.6/1.9's really.
If that makes sense at all..

TedV · « **Reply #26 on:** June 17, 2008, 09:16:51 am »

would the term for "barking" be compresor stall? Compresor stall is when the air behind the compresor builds presure till it backs up and reverses flow thru the compresor, once presure drops it tries to build presure again till it backs up again, repeating this process till something changes to stop it. Suposedly has a suddering sound to it.

Compresor stall will send some wicked vibrations thru the shaft, and yes it will break eventually. Everything I've seen and been lead to belive is the VW turbo's are over sized (at least on the 1.6) and there is no risk of compresor stall in the 20 to 25 psi range.

that being said, I am looking at a T3 with a snapped shaft on the turbine side and no evidence of galling at the bearings, just looks like a grenade went off under the shaft, exploding the housing. Oil presure was fine for a VW, 10 lbs per 1000 RPM. Grainger valve set to open waste gate at 20 PSI. Giles pump so car goes like WOW!!

Cures for compresor stall would be proper sized turbo and blow off valve. Our turbo's are already rather large, and some racing classes wont let you change it :oops: so it leaves the blow off valve. Anyone ever see a blow off valve on a diesel? the pop off valve we have stock only opens in excess of 12 to 14 psi, it will not pop open during shifts or sudden lifts. It is only there to protect the motor if the waste gate seizes in the closed position and boost goes over the 10-12 psi open presure of the waste gate.

Blow off valve on a diesel VW... can that be discussed in a thread without flaming? :lol:

riddleyo · « **Reply #27 on:** June 17, 2008, 09:24:19 am »

here is what an extreme version of turbo surge on a gasser sounds like:
http://videos.streetfire.net/video/True-Turbo-Compressor_163406.htm

zukgod1 · « **Reply #28 on:** June 17, 2008, 09:36:54 am »

Sure does seem there are several names for this.
Bark, surge, flutter, compressor stall.

Doesn't matter how ya word it it's bad.

TedV,
If we could come up with something that would relieve pressure during the throttle uplift it could be done.
Almost need a TPS or something like it mounted to the IP so it would sense up life and open a fast acting valve or a micro switch that would detect when you let off maybe?
There are some of our cars out there equipped with a switch for the A/C I think, turns off the compressor at WOT.

Would have to be electric but I think they are out there.
I wish I would have done something before it cost me a turbo.

foxracer1 · « **Reply #29 on:** June 17, 2008, 03:04:28 pm »

I'm not trying to anger or argue. I'm just trying to help him out and figure out what and why his car is doing this.

Surge is from a turbo making to much boost to low in its rpm range. ie VNTs that are able to make quick boost. Surge is bad.

I think the sound the turbo makes when the throttle is lifted quickly is similar but not surge or bark. The exhaust is no longer pushing on the turbine and the bossted air after the compressor just slows the turbo down. I don't think it is severe enough to cause major damage. My car makes this noise but it sounds very smooth.

Tractor pullers do this same thing when the end the pull and the engine slows really quick. But it sounds more harsh. I can see this being hard on the turbos.

All of the sound is coming from the exhaust side. When i put the 3" DP on versus the stock sized pipe of the same length it got much softer and doesn't do it as easily. Needs to be at a higher boost level.