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Let's put it that way. Unless you completely cut off the oil supply to the turbo, there is basically nothing you can do to make this turbo fail this quickly.
Does not matter if you had boost leaks (on standard tune you get fuel cut), kinked hose (only mechanical boost) or some other issues.
As long as the oiling to the turbo is fine, it will be fine.
Let's put it that way. Unless you completely cut off the oil supply to the turbo, there is basically nothing you can do to make this turbo fail this quickly.
Does not matter if you had boost leaks (on standard tune you get fuel cut), kinked hose (only mechanical boost) or some other issues.
As long as the oiling to the turbo is fine, it will be fine.
First of all Id like to thank everyone so far who has given me advice. I am very grateful.
I love these cars but Im not the most mechanically minded person in the world.
The turbo has been pulled apart and the guy who rebuilt the turbo tells me that the bearings are fine. The bits that are meant to be damaged are both Turbine Wheel and the Shaft, plus this part:
I dont know sorry. I guess hes not going to tell me either.
It's a fundamental part of rebuilding a turbo, anything that spins at 100,000rpm needs to be balanced. It's not the sort of kit that every garage has, only a turbo specialist, which from looking at the state of the workshop, this guy isn't.
sigpic
1991 Audi S2 3B - 2.5 Stroker engine
1997 A6 2.5TDi quattro avant - C4
1976 RD250E / 350LC cafe racer
On another note? The exploded diagram that URS4BOY posted shows a 270 deg thrust bearing, yours in the photo is a 360 deg bearing, did you ask for that ?
Possibility of wrong kit ?
And he must have done loads or rs2 turbos before considering they way he's layed out the pieces!
Must be second nature to him by this stage,
1991 S2 3B Coupe, KW v1, solid sub frames, poly bushed, chipped, about 260 ish
On another note? The exploded diagram that URS4BOY posted shows a 270 deg thrust bearing, yours in the photo is a 360 deg bearing, did you ask for that ? Possibility of wrong kit ?
As far as I know, there is a proper 360 degree bearing that works in these KKK turbos and comes in the new rebuild kits.
The part you didn't know the name of in one of the above posts is the compressor back plate which along with some other components is unique to the K24 7200 and not cheap to replace, I know cause I had to buy one.
And yes as has been said by several other members one really has to try and make a KKK journal bearing turbo of this type fail. The K26 hybrid on my Nothelle converted car was still working OK with no water cooling whatsoever, the return hose was blocked solid and looked to have been that way for a very long time. It did need a rebuild but had covered over 80K miles running 300 BHP.
Hope you get this sorted to your satisfaction though it may easier to source a new turbo than fix your existing one..
1990 B3 2.0 80 quattro.
1992 C4 2.8 Avant quattro
1994 MTM RS2.
1998 B5 TDI quattro Sport.
2000 B5 TQS.
If the MAP sensor doesn't get a boost signal, the ECU doesn't control the N75 WGFV and all you get is the mechanical boost from the WG spring, i.e. about 0.6 Bar. They are looking for excuses but that isn't it. They Fk'd up the rebuild. Done. Period.
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ECU goes to limp mode and you get spring boost.
Also, it's really really unlikely it gets a percentage. It's either kinked or it isn't.
Did you miss the fact that we told you, that nothing short of cutting off the oil supply to the turbo or sticking a physical object into the blades will make this turbo fail?
Apart from a shoddy rebuild of course.
ECU goes to limp mode and you get spring boost. Also, it's really really unlikely it gets a percentage. It's either kinked or it isn't.
I am just responding to think this through (please bear with me).
1. If the green plastic boost signal hose is disconnected from the ECU MAP sensor anywhere between the intake manifold and the ECU, then, yes, the ECU does not know what is going on boost-wise so it does NOT control the N75 WGFV and all you get is the WG spring-based boost, e.g. 0.6 Bar boost. This I know for 100%.
2. The MAP sensor is not based on air flow per se but pressure. That said, air is a compressible fluid so it might take a bit of air flow to translate the boost at the intake manifold to boost at the MAP sensor transducer (the thing that varies the electrical signal based on the boost pressure).
3. A completely kinked green plastic boost signal hose will not transfer boost from the intake manifold to the MAP sensor in the ECU. No feed back = the ECU is likely to go into a limp mode and not control the N75 WGFV = we're back to spring pressure boost (0.6 Bar).
4. A partially kinked green plastic boost signal hose will transfer boost from the intake manifold to the MAP sensor but the volume of air being used to "bend" the MAP sensor transducer might not be enough or quick enough. The ECU would get some feed back but it would be delayed. The ECU would control the N75 WGFV but the delay might be enough to cause the ECU to ask the WGFV for more boost than is actually needed (or was needed a few milliseconds ago). But that should not translate into uncontrollable WG operation and over spinning the turbo. Furthermore, I thought Nik said his boost gauge read 17 psig or 21 psig or something well short of 29 psi (2 Bar) that would start to indicate that the turbo is being over spun by the ECU via the WGFV.
5. If I remember correctly there *is* an issue with the WGFV and the hose to the lower chamber:
Here is what our Marc S (of EFI Express fame) says about the WGFV and the connection of the long leg of the WGFV to the turbo inlet hose from the MAF:
"Under normal operation, air goes from the boost source to the outlet (wastegate). Thats a safety feature. If the valve is busted, it still opens the wastegate."
I know in the past, Marc has raised the red flag that you need to keep the WGFV connected to the wastegate, even if it broken because without it, there is no connection between the turbo and the wastegate to open the wastegate against the wastegate spring pressure. Under that scenario, the wastegate will not open and boost pressures will rise to (likely) destructive levels.
RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avant
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