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Greedy tt DE backpressure problem

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Old Aug 10, 2014 | 03:31 AM
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Default Greedy tt DE backpressure problem

Does anyone of you met with a problem that the turbines blow by the oil lines air back into the engine? Recently we did a test tightness of the clogging intakes and pumping the air in to the collector, came out a few leaks but the strangest was sound heard from under the car it turned out that the air and oil from turbines goes into the engine which indicates that the engine on boost receiving left air from the turbines What could be the reason the turbine or maybe improper oil return (the return is gravity) ???

Last edited by aas350z; Aug 10, 2014 at 03:32 AM.
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Old Aug 10, 2014 | 05:51 AM
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Holy grammar batman!!!!!

I can't even make out what it is your trying to say.
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Old Aug 10, 2014 | 06:49 AM
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That is the longest sentence I have ever read. Hope the FI guys can make cents out of it, so they can help you.
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Old Aug 10, 2014 | 07:26 AM
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Air getting into the oil lines via the turbines... sounds like worn seals. Have you checked for shaft play? But I doubt it happens in boost, there's still more oil pressure than air pressure.
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Old Aug 10, 2014 | 11:11 AM
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I happends on boost. Once per week I have to change rear main retainer because oil leakage and when Im on boost i feel oil smell. Qestion is if turbos are damage end need to be rebuild or it is something with oil lines connections?
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Old Aug 10, 2014 | 11:33 AM
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I think it's more likely that something is pressurizing the crankcase and pushing oil back up into the center sections of the turbo, which then leaks past the turbine side seal, as that seal isn't meant to seal oil at all.
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Old Aug 10, 2014 | 12:15 PM
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I dont have any problem with boost, is stable 1.3 bar but comes late from 4k rpm my problem is that from turbin air back to engine via oil return lines
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Old Aug 10, 2014 | 07:38 PM
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Aas, as a second language your English is very good, but technical explanations can be difficult. If I understand your question correctly, this is what I think you need to consider. When the engine is running a very effective style of labyrinth seal will form around the impeller shaft keeping the compressed air and oil systems completely separated. When you pressurized the charge pipe with the engine off and the turbo at rest, the air was able to easily make its way along the shaft and into the turbo oil drain. This will not occur when the engine is running.

Examples of the labyrinth sealing effects sometimes occur in nature and have been widely used in pressurized equipment for over 150 years.
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Old Aug 10, 2014 | 08:37 PM
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So you probably just need to vent the crank case. It's called blow-by, all boosted VQ's have it to some degree, some more than others.
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Old Aug 10, 2014 | 09:58 PM
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Thanks a lot !
One more qestion currently my crank case vent is connected with intake so vacume is there only when Im not on a boost should i connect vent also with exchaust to avoid this problem? Once again sorry for my english but this is my second language and as you mention I have problems to discus technical issues
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Old Aug 11, 2014 | 06:24 AM
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^ you can connect crankcase vent to turbo air intakes but NOT the manifold. You obviously do not want boost entering the crankcase. Putting a check valve can prevent the boost from entering the crankcase but you still need a place for crankcase pressure to be released during boost.

The exhaust will likely not provide enough vacuum. Either put a filter on top of the crankcase vent or feed a line to the air filter (pre-turbo) in which case I would recommend a catch can in between to trap the oil.

Last edited by rcdash; Aug 11, 2014 at 06:25 AM.
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Old Aug 11, 2014 | 05:11 PM
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My DE used to blow out rear main seals from crankcase pressure as well. I wish the VQ valvecovers were not plastic, so you could weld a -10 outlet on each one. What I would say to do is instead of letting the crankcase crossover hose connect the 2 valvecovers, use each of those as a large crankcase vent. For the back PCV on the left valvecover, could also be a vent or just plug it if using the old crossover ports as outlets perhaps.
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Old Aug 14, 2014 | 02:10 AM
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if enough desire i can start working on aluminum ones mayby by winter. depends how long it takes my stuff to get to ohio i was told two months today. was going to build some for myself for this reason as well as LS coils.

doing it while the engine is getting the new intake and turbo kit is the perfect timing.
Originally Posted by phunk2
My DE used to blow out rear main seals from crankcase pressure as well. I wish the VQ valvecovers were not plastic, so you could weld a -10 outlet on each one. What I would say to do is instead of letting the crankcase crossover hose connect the 2 valvecovers, use each of those as a large crankcase vent. For the back PCV on the left valvecover, could also be a vent or just plug it if using the old crossover ports as outlets perhaps.
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Old Aug 14, 2014 | 06:34 AM
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You can drill and tap plastic. It's just a vent hole. Doesn't really matter
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Old Aug 14, 2014 | 07:28 AM
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you can. i will not. its much to thin of a plastic for me to be interested in that. If anything I would use a proper bulkhead fitting and tackweld or stake the nut on so it cannot back out. Or, just remove the crossover hose and use the 2 outlets from that.

Last edited by phunk2; Aug 14, 2014 at 07:30 AM.
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Old Aug 15, 2014 | 05:02 PM
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this is how my current setup runs. pcv and driver side of the cross over have filters, passanger side of cross over and rear of driver side cover run to catch can with an additional filter. just cleaner to make new covers though and not have a small filter smashed between intake and valve cover
Originally Posted by phunk2
you can. i will not. its much to thin of a plastic for me to be interested in that. If anything I would use a proper bulkhead fitting and tackweld or stake the nut on so it cannot back out. Or, just remove the crossover hose and use the 2 outlets from that.
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Old Aug 16, 2014 | 06:36 AM
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Ok I pluged pvc and intake,valve covers connected with catchtank with air filter. How do you think wil work or I should connect to catchtank pvc with back valve?
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Last edited by aas350z; Aug 18, 2014 at 12:19 AM.
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