V1 Josh's City Goblin - 10 XFE Donor

[jirwin]

That's normal as far as I know. This is the block oil pressure so it's basically straight from the oil pump. It goes down to 40ish when warm.

 

[Rttoys]

Hhmmm since it’s not a dash gauge, I guess I never knew. 80 is still way high. That’s close to blow oil filter off range.

 

[Desert Sasqwatch]

Websites for LNF are reporting 70-80 cold start high idle, 30-35 warm idle, 70-100 at WOT. Looks like an oil restrictor might be a good idea, too high oil pressure can blow past the turbo seals.

 

[jirwin]

The stock opening is ~4.25mm. I ordered two of the only one I could find on Amazon. They are 0.89mm. I figured I can drill it out somewhere in between if I want/need to. I'm assuming the protocol is basically shrink it down until it stops leaking basically?

 

[jirwin]

Would this be a stupid fallback plan? It only has to last me a week lol. https://www.amazon.com/gp/product/B0CZNCVTY3?psc=1

There's a lot more hoses there than on the Z54, but I believe the fittings are all the same. I would need to find a compressor outlet though. I feel like we need a semi specific one for the goblin to fit under the rear cross bar? Probably don't have enough time for that

 

[Gtstorey]

Have you tried to talk to ZZP about what is going on? This setup should be the same as a cobalt, so I would think they would have some idea about what is causing your problem.

 

[Desert Sasqwatch]

Buying that no-name turbo may not even last one week!

The K04 turbo (stock LNF) has oil in/out and (radiator) cooling in/out lines feeding the center section, they are the banjo bolt type. The compressor outlet is a 2 inch with a 2 bolt flange. Someone may have one left over from an upgrade (may have the whole K04 turbo?). The turbine outlet is the 'O2 pipe' that reduces to a 3 inch outlet.

 

[jirwin]

Have you tried to talk to ZZP about what is going on? This setup should be the same as a cobalt, so I would think they would have some idea about what is causing your problem.

Yes, they don't have any idea. They said oil restrictor is not something they want me to do. We've also proved time and time again its not anything to do with the PCV system. This does it regardless of oil cap on or off, turbo capped or not, valve cover breather on or not.

Video: https://streamable.com/wf8l0k

While I'm sure we'll get it figured out in the long run, I'm not sure if I will be able to get it done in time with them. Looking like I'm going to have to cancel Sick Week plans and just eat the cost of entry at this point

 

[Rttoys]

 

[jirwin]

ZZP still think's clogged drain of some kind or residual oil from previous runs where the oil filled the compressor. Its not, but I'm going to humor them and just take the cold side off and fully clean it.

 

[Scott #321]

You can try taking the charge air tube off the turbo and running the engine rpm up a bit. If the turbo seals are bad you will quickly be able to identify that by the oil coming from the compressor outlet.

 

[jirwin]

Not a bad idea. I will ask them before doing that. I don't think idle and whatnot would overspin the turbo when it has no resistance, but I don't want to do anything without their permission that could void a warranty.

 

[jirwin]

Well I may eat my words. It may have been residual oil. Still testing but things are looking up at the moment

 

[jirwin]

5 minutes on idle with no oil cap, capped turbo vacuum port, and venting the valve cover to atmosphere. It pull no oil into the intake for a 3-5 minute idle!

I installed the oil cap and valve cover breather line. It immediately pulled oil again. So... Too much vacuum at the Turbo inlet?

I'm going to clean it all again, and then try doing a check valve I have lying around allowing flow from valve cover to turbo in that direction. Idea would be that the intake manifold will have more vacuum normally, so it will pull it closed, or mostly closed during idle. Under boost the intake manifold check valve will close, pressurizing the crankcase, and allowing the valve cover breather check valve to open, releasing the pressure and feeding the turbo. Also since it's a check valve, it should also kind of meter flow too. Allowing more flow for greater pressure differential, and less for less.

Thoughts?

 

[Desert Sasqwatch]

That sounds logical for the condition you describe. The worst that can happen is it still pulls oil into the turbine. I believe that limiting vacuum as you propose with the check valve should help. Give it a shot and hopefully the situation will improve.

 

[jirwin]

Yep, its just a PITA to keep cleaning lol. If it doesn't work the fall back is just saying screw it and running the exact same setup, but to atmosphere there and capping the turbo. Then the valve cover one will only vent under boost

 

[jirwin]

Did a lot more research last night when I couldn't sleep. Basically what I'm reading is OEM's use a restrictor in the valve cover to turbo line usually in scenarios like this. Sometimes they add a check valve too. This allows some crankcase gases to get evacuated under idle/cruise conditions, but not a ton like mine is currently. So my options are basically...

1. Cap turbo. Valve cover breather -> catch can -> check valve -> atmosphere. This will allow it to push out under boost, but not pull in under idle/cruise, keeping the computer happy with its metered air
2. Valve Cover breather -> catch can -> check valve -> restrictor of some kind (maybe OEM SS TC?) -> turbo inlet. The restrictor should mean less vacuum at the turbo than the crankcase (because of the intake manifold check valve pulling vacuum) so the check valve should stay shut under idle/cruise. Then it would open during boost as normal, but allow positive crankcase ventilation directly into the turbo inlet, which should be nicer to seals and whatnot.

 

[Rauq]

One point where I'm lost is that if your PCV valve is functional, all your crankcase vapors should be going into the intake manifold, no? Unless it's super clogged or just maxed out on flow, there's no way there's more vacuum anywhere in the system than in the intake manifold (when idling).

 

[jirwin]

One point where I'm lost is that if your PCV valve is functional, all your crankcase vapors should be going into the intake manifold, no? Unless it's super clogged or just maxed out on flow, there's no way there's more vacuum anywhere in the system than in the intake manifold (when idling).

That was my thought too!! It still confuses me tbh. When the turbo inlet is plugged and the oil cap is off, there is definitely air being sucked into the oil cap (ie crankcase) which I imagine is coming from the intake manifold check valve. You would think that even if the turbo is pulling vacuum at the inlet, it should be less than what's already in the crankcase, and therefore there should be no problem, but nope! As soon as that line is plugged in I get oil in the turbo! Maybe its because the valve cover line is 8AN and the intake manifold check valve is tiny so its a volume thing? Idk. It really confuses me too.

 

[Rauq]

If you're still down to hear me throw things at the wall to see if anything sticks...

I can't imagine there's any significant vacuum anywhere in the intake pre-throttle body, especially not in comparison to the intake manifold. I read somewhere speculation that you might get -7kPa with a dirty air filter. So while I would expect air to be flowing towards the valve cover instead of towards the turbo, I can't argue with the smoke you're seeing with that line connected versus not. But still, -7kPa through 8AN still shouldn't overcome -60kPa through the PCV.

Does the smoke change if you remove the air filter? Just to reduce any amount of vacuum in the intake tube. And/or, if you remove that line from the valve cover and leave it connected to the turbo inlet, can you feel vacuum on that line?