Audi RS2 Turbo whine/failure

[UrS4boy]

Hey Dave, do you think the 00515 G40 Hall Sender code relates to my turbo issue?

Absolutely not. I wonky G40 Cam sensor will sometimes stop a running engine (as in IrishS2's story and at least one other such case known to me) but usually it will just stop the car from starting. Neither case impacts the turbo negatively. Gives it a rest if anything because the engine is not running.

[Rusty]

If you disconnect the g40 on a running engine and drive it, you get spring boost only.

[UrS4boy]

If you disconnect the g40 on a running engine and drive it, you get spring boost only.

I've never tried that (why would I). However, VAG does agree that you will have less power if the G40 fails while the engine is running:

[twoqu]

Of course we might have been a bit harsh on the turbo guy!
If there was a restriction in the intake or a boost leak then its possible that may have been a contributory factor.
Does the vehicle have the stock airbox or an aftermarket cone filter?
If its bone stock and unmodified and performed as it should have before work commenced then that leaves either the quality of the turbo refresh or the work performed by the mechanic. In an ideal world the mechanic should have ensured that the vehicle did at least meet the manufactures level of boost before handing it back. Obviously we do not know what was removed in order to perform the work but there is basically one pipe in to the turbo and one out! If it made the correct level of boost before and substantially less after then perhaps it indicates a reassembly issue.
Pressumably the turbo did not exhibit any overspeed damage prior to the rebuild otherwise it would have been brought up. It made the stock levels of boost so again presumably there were no significant leaks.
So perhaps this is pointing toward the quality of the workmanship perhaps something as silly as an unsecured boost pipe.
One thing for sure is that low boost and strange noises need investigating immediately as they don't improve without intervention. Once the damage is done its difficult to point the finger at anyone in particular unless of course you are at fault.

[prj]

So, I told you on the first page, that you should get a lawyer. Especially if you have receipts for everything.
Which part of my advice was wrong then?

Overspinning trying to 20 psi? The STOCK map is 21 psi. From factory.
The turbo's choke line on the god damn compressor map is the MOST efficient at 21 psi.
This turbo is BUILT and optimized from factory to run 21 psi - and people run them to 30 psi all the time with no issues.

Now, you have two options:
1) You fight for your rights and for that you need legal counsel in the country you live in.
2) You suck it up and move on.

Anything else is a waste of time.

[Rikki Kitto]

So, I told you on the first page, that you should get a lawyer. Especially if you have receipts for everything.
Which part of my advice was wrong then?

Overspinning trying to 20 psi? The STOCK map is 21 psi. From factory.
The turbo's choke line on the god damn compressor map is the MOST efficient at 21 psi.
This turbo is BUILT and optimized from factory to run 21 psi - and people run them to 30 psi all the time with no issues.

Now, you have two options:
1) You fight for your rights and for that you need legal counsel in the country you live in.
2) You suck it up and move on.

Anything else is a waste of time.

Well said, a bit blunt but true. There is a third option but I don't think it's legal

[Golfboy666GTI]

So, I told you on the first page, that you should get a lawyer. Especially if you have receipts for everything.
Which part of my advice was wrong then?

Overspinning trying to 20 psi? The STOCK map is 21 psi. From factory.
The turbo's choke line on the god damn compressor map is the MOST efficient at 21 psi.
This turbo is BUILT and optimized from factory to run 21 psi - and people run them to 30 psi all the time with no issues.

Now, you have two options:
1) You fight for your rights and for that you need legal counsel in the country you live in.
2) You suck it up and move on.

Anything else is a waste of time.

Dont worry I am, Im not prepared to suck it up.
Its a bit he said, she said though.

Hes going to say: The kinked vac pipe to the ECU is the reason for the issue.

Im going to say: Yes the vac pipe was kinked but car should run .6 bar in limp mode via the WG.

But I need some proof, I dont think a print out of this thread is going to cut the mustard? I need something on a letterhead from a tuner or Audi dont I?

[dm80]

get prj round in person to boot his baws. hth

[220bhp]

So, I told you on the first page, that you should get a lawyer. Especially if you have receipts for everything.
Which part of my advice was wrong then?

Overspinning trying to 20 psi? The STOCK map is 21 psi. From factory.
The turbo's choke line on the god damn compressor map is the MOST efficient at 21 psi.
This turbo is BUILT and optimized from factory to run 21 psi - and people run them to 30 psi all the time with no issues.

Now, you have two options:
1) You fight for your rights and for that you need legal counsel in the country you live in.
2) You suck it up and move on.

Anything else is a waste of time.

Dimitri I see your reply's are delivered as gently as ever

[prj]

Dont worry I am, Im not prepared to suck it up.
Its a bit he said, she said though.

Hes going to say: The kinked vac pipe to the ECU is the reason for the issue.

Im going to say: Yes the vac pipe was kinked but car should run .6 bar in limp mode via the WG.

But I need some proof, I dont think a print out of this thread is going to cut the mustard? I need something on a letterhead from a tuner or Audi dont I?

From the Motronic manual:

Self-diagnosis:
Self-diagnosis makes a difference between types of fault: "signal too small" and "signal too large".

Basically what it does is it compares throttle position to manifold pressure, and if for example it is not reading boost properly when the pedal is to the floor, then it will throw a "signal too small" code.
If the boost can not escape back to the manifold quick enough, then when you lift the throttle it will throw a "signal too large" code, because throttle position is zero and measured pressure is high.

You will have to take my word on this one - only proof I can give you is assembly code from the ECU. Not sure anyone besides me will make much sense of it though.
Your first course of action is have an independent expert examine the turbocharger though.

[Golfboy666GTI]

Ive just got back from my visiting my Father whos currently having cancer treatment to find a email with the two attached "Independent" Turbo failure reports.

[UrS4boy]

Ive just got back from my visiting my Father whos currently having cancer treatment to find a email with the two attached "Independent" Turbo failure reports.

Yeh, "Independent". Sounds more like the report writers colluded (e.g. talked on the phone) to get the story "right". Sounds like asking two doctors whether the third doctor botched the surgery. They always close ranks and support each other.

To me "Loctite" is a red flag. I thought the nut had to be staked in place.

Sorry for this outcome. Hope that they still offer you something.

Dave F

[Pat D]

I take it these were not requested by you and the company at fault organized them?

[Golfboy666GTI]

I take it these were not requested by you and the company at fault organized them?

I told the guy who rebuilt the turbo that I wasnt happy with his findings and that the car should run .6 Bar limp mode if the car has issues.

He then said he would get an independent report done. I didnt ask for or request this.

[twoqu]

I think the biggest issue in hindsight is that the turbo was not build by a Turbo specialist, i.e. a company that deals in the service and repair of turbochargers and has the specialist tools, equipment and experience.
If the turbo was dismantled and rebuilt with the tools featured in the picture in an earlier post then its highly likely it was damaged prior to the rebuild.
There are specialist (expensive) holding blocks that are used to hold the turbine wheel so that no bending load is applied to the other end of the shaft when dismantling. If they held the turbine shaft with a spanner one end and a rachet at the other that might have bent the shaft to start with. If it was bent when reassembled then its quite possible that the nut was never at the specified torque/angle. It might also account for the damage in the one particular place noted in one of the reports.
So an alternative explanation might be that a loose compressor nut was responsible. How you would be able to prove that is the issue. Did it become loose due to the overspeeding or was it already loose and the turbo overspeeded. The loctite is interesting. I am not sure whether a sealant is used/necessary on l/h threaded turbos due to their self tightening nature. I don't think the one I dismantled did but it had been dismantled before as evidenced by the witness marks. I don't think any turbo nut would be staked!
Even if we accept the turbo damage was caused by overspeeding, again how is that attributable to you. As I understand it the car performed as it should have before the rebuild/refitting and did not after. So which one of those processes was responsible for the lower boost evident when you got the vehicle back? If its not the quality of the turbo rebuild that leaves the mechanic. He returned the vehicle basically with a degradation in its performance that hinted quite strongly as a turbo or reassembly issue. You compounded the problem by driving it around for 6-7 months without investigating.
I guess you could interrogate the turbo guy for how it was dismantled, with what specialist tools and what torque/angle was used to tighten it etc. Did this place balance the turbo using a VSR machine?. Again an industry standard these days. Ultimately I doubt whether anybody could determine what actually happened to a box of bits, other than NASA!
These are only my amateur opinions. You have interogated the ecu and there are no Map sensor codes evident. There are some safeguards build into the Motronic management as I understand it to prevent serious damage. So that only leaves the quality of the rebuild and/or the quality of the workmanship of the mechanic. You will have to determine all the possible causes for the turbo overspeeding and then then rebutt them with the facts.