Turbo bark (compressor surge)

[R.O.R-2.0]

so, my turbo barks every time i shift and i have ANY sort of boost..

ive been under the impression that turbo bark is bad?

[theman53]

CRSMP5 turbo is living and IIRC his barks every shift.

[Blocksmith]

Not an expert on this by any means, but from the reading I've done that barking sound is actually the compressed air in the intake manifold / IC following the path of least resistance--which happens to be back through compressor wheel at that particular moment, traveling BACKWARDS through the turbo. It happens when you let off the throttle to shift, which means that the motor isn't providing the turbo with enough exhaust pressure to continue to compress the intake air; this means that you've got 20psi of pressure in the intake that the engine can't use b/c the rpms are too low, and the path of least resistance for that pressurized air is simply to go back through the turbo.

From what I've read it isn't such a huge problem if it only does it once in a while, but supposedly continuous barking spells a guaranteed turbo failure; only a question of time.

Having said that, the only thing I can think of to alleviate the problem would be some sort of one-way check valve right after the turbo, and I've never heard of anyone doing that.

[8v-of-fury]

How many rpm's are you dropping on a shift? Are you granny shifting so that you return to idle every time? kidding.

That seems weird that least resistance would be to fight the already turning compressor wheel.. And not jsut continue its path through the motor and through the exhaust turbine, considering even when you take your foot off the pedal to shift the engine is still processing air.

[R.O.R-2.0]

How many rpm's are you dropping on a shift? Are you granny shifting so that you return to idle every time? kidding.

That seems weird that least resistance would be to fight the already turning compressor wheel.. And not jsut continue its path through the motor and through the exhaust turbine, considering even when you take your foot off the pedal to shift the engine is still processing air.

yea, its not like the throttle plates close when you shift on a diesel..

[spencebm]

not this again...get off the internet

[R.O.R-2.0]

not this again...get off the internet

what are you talking about? i just want to be sure that im not gonna kill my turbo before i get a proper downpipe and exhaust fabbed up..

[8v-of-fury]

not this again...get off the internet

Are you drunk again..

[CRSMP5]

ok ill ask.. wtf is bark?? i get a pm asking.. theman says i have it.. but not a clue to what you speak..

when i say bark.. which i cannot say i have.. its the tires with not enough traction..

i also do not granny shift.. my rpm drops very little between shifts..

my boost is set to 18-21psi

[JerryGTD]

i feel stupid now 

the K24 performs better than the VNT.

i think it even spools as quick, or maybe even quicker..

wastegate unhooked, and i peak 20psi in every gear..

its got compressor surge like a mofo tho.. like every time you shift, the turbo barks.. what gives?

Do you think it would still bark if the wastegate was hooked up?

[81 vw pu]

My k24 barks, but I only hear the bark after 13-14 psi shifts. Nothing abnormal when shifting down low.
If I stay in to boost longer the bark gets louder. With wastegate hooked up (no MBC) 8-9 psi no bark.
Currently I have no exhaust, just a 2.5" downpipe that just enters the shift rod tunnel.
The GT15 I took off about 2 months ago did not do this when ran with a 2" downpipe only.
The bark occurs about the same time a blow off valve would open on a gasser.

[RabbitJockey]

My k24 barks, but I only hear the bark after 13-14 psi shifts. Nothing abnormal when shifting down low.
If I stay in to boost longer the bark gets louder. With wastegate hooked up (no MBC) 8-9 psi no bark.
Currently I have no exhaust, just a 2.5" downpipe that just enters the shift rod tunnel.
The GT15 I took off about 2 months ago did not do this when ran with a 2" downpipe only.
The bark occurs about the same time a blow off valve would open on a gasser.

what intake setup do you have?

i know ror has an intercooler and a gas intake which would both add volume, so when you let off the the gas and stop giving it fuel, the exhaust side loses the driving pressure so nothing is keeping the pressurized air in the intake/intercooler piping so it can easily revert out the same way it came in, if the engine does not consume that pressurized air fast enough.

[Blocksmith]

what intake setup do you have?

i know ror has an intercooler and a gas intake which would both add volume, so when you let off the the gas and stop giving it fuel, the exhaust side loses the driving pressure so nothing is keeping the pressurized air in the intake/intercooler piping so it can easily revert out the same way it came in, if the engine does not consume that pressurized air fast enough.

Nicely put; you said what I was trying to say, only much more concisely.

[81 vw pu]

what intake setup do you have?

i know ror has an intercooler and a gas intake which would both add volume, so when you let off the the gas and stop giving it fuel, the exhaust side loses the driving pressure so nothing is keeping the pressurized air in the intake/intercooler piping so it can easily revert out the same way it came in, if the engine does not consume that pressurized air fast enough.

Just as it reads in my sig. 1.6td intake and intercooled as well.

Kinda sound like ROR and I need a gasser BOV???

Any input on long term effects of running it like this?

[R.O.R-2.0]

what intake setup do you have?

i know ror has an intercooler and a gas intake which would both add volume, so when you let off the the gas and stop giving it fuel, the exhaust side loses the driving pressure so nothing is keeping the pressurized air in the intake/intercooler piping so it can easily revert out the same way it came in, if the engine does not consume that pressurized air fast enough.

Just as it reads in my sig. 1.6td intake and intercooled as well.

Kinda sound like ROR and I need a gasser BOV???

Any input on long term effects of running it like this?

but, how to operate it?!