Turbocharger drainback video

[Christopher Schimke]

Fast Forward posted thsi video on their FB page, but it answered a question that I always wondered about - If the oil line going into the turbo has oil pressure going to it from the engine, how can the drain line angle be so critical? Shouldn't the oil pressure simply push the oil right on through? Turns out the answer is...no!

I'm not a turbo expert, but I assume most/many turbochargers are built like the one in the video (with a "piston ring" in the "oil seal holder"). If that is the case, this video clearly shows why it is so important to get the turbo clocked properly and to have a large drain line with plenty of angle for the oil to drain freely back to the oil pan.


Link

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"Sometimes you have to build a box to think outside of." - Bruce (not Springsteen)

*Custom wheel hardware for Audi/VW, Porsche and Mercedes wheels - Urethane Suspension Bushings*
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[Escorial Syncro]

Wow, that's an eye-opener. Amazing how sensitive that seal is to any kind of back pressure! I guess on our crazy rigs you clock it at 12 o'clock and try to keep crank case pressure system in top working order. An hope for best, of course.

Thanks for posting Chris
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Joel Lane
1985 Vanagon converted to syncro, ALH TDI, Reimo Primus top with Westy interior
2002 Toyota Tundra 4x4
1974 Honda CL360 Scrambler (for sale!)

[Christopher Schimke]

Yeah, I was pretty surprised to see how sensitive it is too. I had no idea.
_________________
"Sometimes you have to build a box to think outside of." - Bruce (not Springsteen)

*Custom wheel hardware for Audi/VW, Porsche and Mercedes wheels - Urethane Suspension Bushings*
T3Technique.com or contact me at [email protected]

[AndyBees]

Amazing! This is really interesting.

The Turbo on my ALH engine in the Vanagon is laying over on 50 degrees (OE in the Jetta is 22 degrees) which results in a "trap" configuration for the drain pipe. However, generally I only have to add less than a quart of oil per 10k mile oil change interval. Engine has 208k miles on it.

I'm thinking the oil seal (metal expansion ring) is set-up differently on the VNT15 Turbo. It's been a while since I last torn one down. (Well, on second thought, I believe it is.)

I have an Evac-scavenger to handle blow-by crankcase pressure! It is connected to the CCV on top of the valve cover and down stream of the CAT but before a straight-thru glaspak muffler.

Here is an actual angle shot of the drain...

Below are three shots of the Evac-scavenger set-up. (The red butterfly thingys are gone )
This set-up has been in operation over 80k miles with no issues!

EDIT: Below, in this pic, the CAT is to the right with the exhaust flowing from right to left to the glaspak.

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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[Gizmoman]

Great thread for those of us running TD's!

I like the scavenger concept Andy. Hard for me to tell from the photos - I'm assuming your tapped into the exhaust? I also notice you placed it at a section just before it expands - increasing the vacuum even more - ingenious.
Currently I have a 1" hose running from the AAZ's 3-port CCV output to my intake pre-turbo (no venturi) and am worried I may coat the inter-cooler guts with crud. I don't seem to have any oil in the air but it's really too early to say for sure. Running this to the exhaust seems like much better idea - especially with the venturi type connection.

Also, I don't see any vent hose coming from the block to the CCV (hockey puck). - must be an AHU thing?
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82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[MarkWard]

Interesting video for sure. The amount of oil leaking past the shaft would empty the block in 5-10 minutes. There must be something else at play. Like Andy, I've got close to 50,000 miles on a similar setup and still don't need to add oil between changes. My breather goes to the atmosphere. I have a Mann breather separator but have not found a place to mount it. Thanks for the video Christopher.
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[AndyBees]

Gizmoman,

Yeah, the CCV puck on top of the Valve Cover is the only point for venting the crankcase on an ALH engine. Since, I don't use the OE oil dip-stick tube, I've considered using it as a supplement for venting (presently plugged).

Yep, the Evac-Scavenger is located at the down stream end of the CAT as it enters the "straight-thru" glaspack. Originally, I installed it pre-CAT ... did not work at all.

Should be noted: The Evac-Scavenger is easy to unscrew and clean. I clean it at oil change (10k miles). There is an oil mist in the vent gases, add them to the exhaust and there's a soot mix build-up.

As for oil in the pressure pipe down stream from the Turbo..... yes, there will be as the Turbo will lose some oil, particularly during engine idle RPMs as there is virtually no "back-pressure." This is just a fact and sort of contrary to the demonstration. My Inter Cooler lays flat, thus basically no place for large amounts of oil to pool like in the OE arrangement of the IC in the Jetta/NB/Golf.

I believe the back-pressure from Exhaust Gas on the Turbine side and Compressed Air on the Impeller side of the Turbo may be complimentary in keeping the oil out considering the drain configuration that Mark and I have with our Turbos.

I've considered modifying the drain on my Turbo just to have peace of mind. This Demo has certainly re-sparked my interest.
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[Gizmoman]

My interest in case-venting came primarily from the desire to stop oil leaks. I simply couldn't get my stamped steel valve cover to seal just venting to an open catch-bottle. I brazed the CCV port shut and re-located it so the CCV sits level. Libby suggested getting the CCV level and it certainly makes sense. This stock port (with 50° lean) and it's seal was also a leak source.

While I was fiddling with it, I checked block and valve cover pressures using a DIY manometer I made to tune motorcycle carbs. At idle, the valve cover showed .6" WC [.02 psi] and the block showed .3" WC. As I can hit 20 lbs of boost and often do getting on the freeway, it was apparent I was building substantial case pressures.

Adding the hose to the pre-turbo intake completely stopped the valve cover leaks and that's with zero silicone applied to a new rubber gasket! I still haven't stopped every leak but it's been reduced by 75% at least

As far as I can tell, my Holset turbo doesn't leak oil at all.
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82 Vanagon Westy - AAZ 1.9 TD, HE200 Holset, WAIC, 27.75 dia tires, Electric power steering, 5-speed AAP w/.078 5th
Oversize spare carrier - stock location (no longer for sale).

[narendra.vw]

pic of my Turbo drain after re-clocking.

TDI turbo drain diagram.

Oil drain TD setup.

[damac]

i don't understand the technical stuff. i got a mtdi alh project and blindly connected the valve cover puck hose to a port on my airbox before the air filter.

i see there is a fitting for the oil fill cap that allows for another hose to be connected. could i use that for the heck of it and connector another hose to t into the hose at the airbox and have it help at all?

or would going around that puck cause some trouble, maybe more droplets of oil with potential for runaway?

[rmcd]

My previous catch can was connected to the ccv hole and atmospheric breather. Turbo, dip stick and other areas leaked a bit of oil.

I installed a Mann Provent200 connected to the ccv vent hole where crankcase fumes would presumably be extracted via a vacuum provided by a hose connected to the turbo intake.

The Provent fittings are 1”. The ccv hose is maybe 1/2”. I stepped up to 1” silicon hose right after the transition fittings. So far no leaks but I’ve only gone a few hundred miles.

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VW LT40 build. Like a Vanagon but 30% larger in every direction and 40% slower even in metric.
https://www.thesamba.com/vw/forum/viewtopic.php?t=749359&highlight=

[Gnarlodious]

[jberger]