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Chronic turbo leak - I have tried it all I think

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Old 12-06-2016, 09:52 PM
  #16
DRPM
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If you live near NJ, call Protosport
They are pros on TT's
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Old 12-07-2016, 09:13 AM
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Originally Posted by DRPM View Post
If you live near NJ, call Protosport
They are pros on TT's
Very close, sweden...
My last resort solution is to send it to RS Tuning in germany but they are even more expensive than Sweden.
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Old 12-07-2016, 09:26 AM
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Originally Posted by DRPM View Post
If you live near NJ, call Protosport
They are pros on TT's
https://rennlist.com/forums/993-turb...t-turbo-2.html

I checked that thread you posted a while back
Did the test Kevin suggests in that thread.
Almost no oil coming out, less than what Kevin indicates there so not a filter issue.

How did you end up solving your smallish leak/puff of smoke at start up ?

Thanks a lot !
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Old 12-07-2016, 09:52 AM
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What's your oil pressure like - could the relief valve be jammed?

Did the leaking start after the rebuild? Can you ensure the turbo vent lines are routed to the right place and are not seeing boost pressure but rather seeing crankcase pressure?

And what's the oil level on the dipstick when the engine is hot?
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Old 12-07-2016, 11:15 AM
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Originally Posted by Felix View Post
What's your oil pressure like - could the relief valve be jammed?

Did the leaking start after the rebuild? Can you ensure the turbo vent lines are routed to the right place and are not seeing boost pressure but rather seeing crankcase pressure?

And what's the oil level on the dipstick when the engine is hot?
The oil pressure is high. When reving it goes almost to 8Bar. My mechanic 1st thought it was the issue and checked the relief valve. It was working normaly... Since he had another stock TT there (the one I borrowed the used turbos that were not leaking from) for repair he tested it as well and got the same results for the oil pressure.

Note that the turbos leak on idle. There I have between 1,5 and 2 bar when the oil is warmed up.

Oil level is at MIN on the stick
Vent lines checked and rechecked ! Also the test with breather lines unplugged, engine running, no oil coming out of the vent holes but turbos steal leaking point to "something else" I guess.

The oil leak started after a hot day at the track, check the picture. That track has a lot of long straight lines. At the time I had a relatively restrictive exhaust to pass the 95decibel checks and it got really warm back there. The car was really moving though... but the day after drip drip drip
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Old 12-07-2016, 11:38 AM
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The lubrication diagram I have for the 993tt (from Volume 1 of the factory shop manual) says the pressure relief valve opens at 5.3 bar and the safety valve at 9 bar. Could this be the cause?
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Old 12-07-2016, 11:56 AM
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Originally Posted by Felix View Post
The lubrication diagram I have for the 993tt (from Volume 1 of the factory shop manual) says the pressure relief valve opens at 5.3 bar and the safety valve at 9 bar. Could this be the cause?
When we went through all the possible sources of failures and tests that were made we went through this with my mechanic. He ruled it out after comparing to the other TT and because the turbos still leak at idle when oil pressure is low.

Thx for the technical details though
And sure worth another check.
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Old 12-07-2016, 12:04 PM
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I don't confess to know the intricacies of the turbo's oil seals but if the oil pressure is too high isn't it possible that the seals have been damaged and will leak at lower pressures? Does FVD do something special to their turbos in that area making them more susceptible to damage from too high oil pressure while stock K16s (as on the other car and the ones you borrowed) cope fine? A fair bit of speculation on my part but as you seem to be at a dead end I thought I would throw all this out there.

"How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?" - Sir Arthur Conan Doyle

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Old 12-07-2016, 12:28 PM
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Originally Posted by Felix View Post
I don't confess to know the intricacies of the turbo's oil seals but if the oil pressure is too high isn't it possible that the seals have been damaged and will leak at lower pressures? Does FVD do something special to their turbos in that area making them more susceptible to damage from too high oil pressure while stock K16s (as on the other car and the ones you borrowed) cope fine? A fair bit of speculation on my part but as you seem to be at a dead end I thought I would throw all this out there.

"How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?" - Sir Arthur Conan Doyle

I run standard K16s and I purchased a set of new ones direct from BW to FVD to me (mostly I don't need more power, just more skillz). Of course who knows what has happened at BW in the mean time ? Are today's K16 the same as in the 90ies ? I bet they are not.

Thanks a lot it's appreciated
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Old 12-07-2016, 12:44 PM
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no worries and good luck. please do report back on how things go.
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Old 12-08-2016, 09:50 AM
  #26
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For the record - Answer from Porsche AG is that the high oil pressure is normal as the pressure relief valve cannot keep up when Revs go up quickly.

For what it's worth.

They were not that helpful otherwise.
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Old 12-08-2016, 01:43 PM
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It is interesting that there are two relief valves - seems to imply that it's known that the first one can't always do its job.

I can just about accept that if the revs are rising fast the valve may not be able to respond quickly enough but it looks like a simple spring-operated valve with no dampening so I'm a little puzzled. And at steady revs you should never see more than 5.3 bar oil pressure or the first valve is clearly not doing its thing.

When was the last leakdown test done? If you remove the dipstick is there any pressure in the crankcase?
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Old 12-08-2016, 02:22 PM
  #28
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Originally Posted by Felix View Post
It is interesting that there are two relief valves - seems to imply that it's known that the first one can't always do its job.

I can just about accept that if the revs are rising fast the valve may not be able to respond quickly enough but it looks like a simple spring-operated valve with no dampening so I'm a little puzzled. And at steady revs you should never see more than 5.3 bar oil pressure or the first valve is clearly not doing its thing.

When was the last leakdown test done? If you remove the dipstick is there any pressure in the crankcase?
The last leakdown was done in September this year. The car has not been driven since.

Previous one was in the winter of 2015. Good results as well.

Done at 2 different places.

No pressure in the crank case that I can feel. No vaccuum or no force that would push the dipstick out.

I will check with my mechanic if the high oil pressure was a peak pressure or steady.

Both my mechanic and Kevin lean towards the turbos. Searching Rennlist Kevin has indicated that brand new KKKs or rebuilt KKKs 16s or 24s can leak from day 1 :-(
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Old 12-14-2016, 09:41 PM
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Originally Posted by Vince964T View Post
https://rennlist.com/forums/993-turb...t-turbo-2.html

I checked that thread you posted a while back
Did the test Kevin suggests in that thread.
Almost no oil coming out, less than what Kevin indicates there so not a filter issue.

How did you end up solving your smallish leak/puff of smoke at start up ?

Thanks a lot !
I bought and installed RUF oil return lines
I already had the check valves on the Turbos
Done
RUF Germany may be able to help you.
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Old 12-16-2016, 12:55 PM
  #30
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Originally Posted by DRPM View Post
I bought and installed RUF oil return lines
I already had the check valves on the Turbos
Done
RUF Germany may be able to help you.
Thx
I have their return lines already !
My new turbos will be shipped back to FVD
Hopefully their supplier knows what to do (I doubt it !)
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