20v keep blowing turbo, help please

[george21]

Its quite a minefield!

http://www.s2forum.com/forum/showthread.php?t=18357&highlight=oil

Shame the Turbo guy can't be more definitive as that would help. If was from being stalled then that suggests the BPV. Not impossible to install the BPV backwards or even a new component to be be faulty. If it was through surge then thats a function of the turbo characteristics which may or maybe not be solvable through careful mapping or worst case a better choice of turbo.
If its not on the car, i.e the oiling system, then its might be something to do with the incompatability of the turbo with your goals. The K7400 has a relatively small turbine which makes it a poor choice for elavated power levels. A K27 hybrid can be a pick n mix of many components which might not be compatable. Do you know the exact spec in terms of comp wheel and turbine housing etc?
Is the software compatable with the turbo?
I am guessing that the car did not have the same characteristic before so basically its a matter of backtracking to see what has been changed and how that might effect things!

What turbo rebuilder says is that shaft is twisted on the cold side, compressor wheel damaged and he can see some bronze on the shaft from the bearing,
oil seals on the cold side and hot side are good.
So bronze on the shaft means that it touched it at some point because of the oil starvation or when shaft was twisted from stalling then it was rubbing on the bearing. Turbo was bought new from forum member "hoffer"
K27 hybrid. I don't remember spec from top of my head as turbo is at the rebuild shop.
All i remember that hot side is k26/6

[george21]

I welded 3" maf hose from stainless steel, so collapsing it is not possible. Dump valve checked and rechecked, boost from turbo goes to the side of it, bottom to the maf pipe.

[Greg_S]

On the MAF house later pipes hand a metal coil to stop them collapsing

[newsh]

What MAF hose are you running, is it the original one and is it old and soft? It's possible for the turbo to collapse the MAF hose at high RPMs and boost, that will stall the turbo.

Otherwise you need to make sure the DV is opening when the throttle closes and the N75 is connected correctly and there are no boost leaks anywhere in any of the small pipes.

If the DV doesn't open you get a lot of fluttering sound through the airbox..

[twoqu]

Good question, i thought it is the best oil to use !
Am i wrong?

Its quite a minefield!

http://www.s2forum.com/forum/showthread.php?t=18357&highlight=oil

Shame the Turbo guy can't be more definitive as that would help. If was from being stalled then that suggests the BPV. Not impossible to install the BPV backwards or even a new component to be be faulty. If it was through surge then thats a function of the turbo characteristics which may or maybe not be solvable through careful mapping or worst case a better choice of turbo.
If its not on the car, i.e the oiling system, then its might be something to do with the incompatability of the turbo with your goals. The K7400 has a relatively small turbine which makes it a poor choice for elavated power levels. A K27 hybrid can be a pick n mix of many components which might not be compatable. Do you know the exact spec in terms of comp wheel and turbine housing etc?
Is the software compatable with the turbo?
I am guessing that the car did not have the same characteristic before so basically its a matter of backtracking to see what has been changed and how that might effect things!

[K Simmonds]

It's a bit think unless you live somewhere really hot, 10/50 is about the best for our climate IMO.

[george21]

What was the thinking behind using a 20/50 grade oil rather than say a 5 or 10/40 or even a 10 or 15/50?

Good question, i thought it is the best oil to use !
Am i wrong?

[twoqu]

What was the thinking behind using a 20/50 grade oil rather than say a 5 or 10/40 or even a 10 or 15/50?

[twoqu]

Might not be of much use but this is the first time I have ever seen oil pressures mentioned for the K26. They are for the Porsche variant but should be comparable.
Max warm oil pressure 5 Bar.
Max cold oil pressure 8 Bar.

http://www.full-race.com/store/turbos/borgwarner-airwerks/borgwarner-k26-turbo.html

[quattro-nick]

have you checked that the tube that go from dumpvalve back to hose turbo inlet is open? and is the litte vacuum tube from dumpvalve to intake okay,no leaks and good connection?

[george21]

yep, shaft is twisted, cold side f---ed

turbo man says that it is likely that turbo stalled , surge, which means faulty dump valve or n75 or or.... i don't know anymore.
(dump valve and n75 new from germanautospares)

[quattro-nick]

good luck!
keep us posted

[george21]

i still think it's an oilfeed problem
i drove with 1.5 bar redline with rs2 turbo for 1000km without problems
maybe you can replace the oilfilterhousing?
do you have a egt meter in the car?

Turbo rebuilder says that twisted shafts it's most likely turbocharger stalling on high boost, (n75, dump valve?) i will know more tomorrow then it's taken apart.

[george21]

It does its p/n 034115197, shown as a supplementary part under the complete oil pump

It doesn't show here tho!
http://forums.audiworld.com/audi-ori...95/?styleid=12
or here

[quattro-nick]

i still think it's an oilfeed problem
i drove with 1.5 bar redline with rs2 turbo for 1000km without problems
maybe you can replace the oilfilterhousing?
do you have a egt meter in the car?