interesting info on turbo drain angle...

[jimbote]

more for the 50 degree vanagon crowd but interesting nonetheless.

 

[AndyBees]

Jimbote, thanks for sharing this info...

So, in my experience, almost 90k miles on 50 degree angle with no issues (no excess oil consumption). However, on level ground, with the engine idling (30 minutes or more) oil will appear around the exhaust Donut Gasket............

(These pics are when I was installing a new exhaust system [stainless])

See below, there at the spring-loaded joint.

In the photo below, you can see there is a "trap" in the Turbo drain pipe with the engine laying over on a 50 degree angle.

 

[jimbote]

i do recall you running your turbo @ 50 degrees and had this in mind while i've been setting up my 50 degree tdi... i considered just leaving it alone at 50 but i might be the one sucker that has an issue with oil consumption.

 

[Mongler98]

Cant you rotate the core so it points to the drain port more? Not a lot of room. I would plug that hole and go strait into the pan down lower and wrap it in some heat wrap.

 

[AndyBees]

Cant you rotate the core so it points to the drain port more? Not a lot of room. I would plug that hole and go strait into the pan down lower and wrap it in some heat wrap.

The Core could probably be rotated with lots of machining, boring, tapping, etc. It would be a heck of a challenge for a machinist. Or, the manifold could be cut and welded back on with a more up-right angle.

The trap in the drain pipe is really not the problem with oil draining from the Turbo housing. The problem is that a 50 degree angle raises the drain hole upwards resulting in a "bowl" of ponding oil inside the Turbo housing. The oil level apparently gets high enough to allow it to drain out around the expansion ring seals on either end of the Turbine Shaft. This is especially an issue with the engine idling as there is virtually no back pressure from the exhaust or the pressure side.

Even under ideal conditions, these Turbos dump oil into the intake system and the exhaust.

There is a video somewhere showing only a slight change in angle results in oil getting by the expansion ring seals. Seems I saw it over in the Samba.

 

[jimbote]

with the gt1749vc turbo i'm using it's possible to easily clock it to straight down drain...just have to modify the vnt actuator bracket (slotted adjustable is on the way) ...i was talking to one of the techs gpop turbo a few years ago and asked if they placed the ring gap @ 12 o'clock in relation to turbo mounting, he stated they did in order to help control oil consumption.

 

[Mongler98]

The Core could probably be rotated with lots of machining, boring, tapping, etc. It would be a heck of a challenge for a machinist. Or, the manifold could be cut and welded back on with a more up-right angle.

The trap in the drain pipe is really not the problem with oil draining from the Turbo housing. The problem is that a 50 degree angle raises the drain hole upwards resulting in a "bowl" of ponding oil inside the Turbo housing. The oil level apparently gets high enough to allow it to drain out around the expansion ring seals on either end of the Turbine Shaft. This is especially an issue with the engine idling as there is virtually no back pressure from the exhaust or the pressure side.

Even under ideal conditions, these Turbos dump oil into the intake system and the exhaust.


There is a video somewhere showing only a slight change in angle results in oil getting by the expansion ring seals. Seems I saw it over in the Samba.

really? i have seen very few turbos that cant be lightly modified (usually brackets) to get the oil feed correct.
its less than ideal especially for a performance application. maybe get some custom AN fittings made to make that turn sooner right out of the turbo rather than later?
aslo why cant it go into the oil pan? or is the angle of the engine making that area of the pan just fully submerged?

 

[jimbote]

really? i have seen very few turbos that cant be lightly modified (usually brackets) to get the oil feed correct.
its less than ideal especially for a performance application. maybe get some custom AN fittings made to make that turn sooner right out of the turbo rather than later?
aslo why cant it go into the oil pan? or is the angle of the engine making that area of the pan just fully submerged?

the vnt15 turbo chra design does not lend itself to being rotated at all... it has nothing to do with external modifications (easy)... it's the internal vnt mechanism that would require very accurate machining to even begin clocking the chra... now the gtb series is much more easily clocked due to it's self contained chra vnt mechanism.

 

[AndyBees]

Mongler98 ......... up there ^^^

Trust me, if the Garret VNT15 could have been simply clocked, I would have done it. After running mine over 80k miles as seen above with no issues, I say in my case it is a worry less - drive more scenario !

 

[CakeD]

Just battling a problem with oil drain on and ALH vanagon conversion right now.

http://forums.tdiclub.com/showthread.php?t=508539

Im surprised the VNT15 in the stock drain location has no issues at 50deg. There must be just enough of an air gap to allow the CCV pressure to pass above the oil return flow as to not put pressure and push the oil back up the return.

I have a GT1749va mounted right now with the drain at about 35deg and its no issue when returning into a jug of oil. Unfortunately the longitudinal manifold puts the turbo really far out so the return to pan is less than a 45deg slope

Andy, you probably get a tiny bit of oil pushed past the turbine seal at idle. Do you never get any smoke? Think I saw you have an CCV scavenger so you probably get the highest ccv pressure at an idle

 

[AndyBees]

CakeD ......... interesting point about the crankcase pressure during idle...

This guy is from India. He commented and had input on the ALH install in my Vanagon very early on... This is his work ...


https://www.thesamba.com/vw/forum/viewtopic.php?t=682839&highlight=turbo+angle

 

[AndyBees]

Okay, below is a YouTube video that I saw in the Samba a couple of years ago.

Narrative/discussion with video below

https://www.thesamba.com/vw/forum/viewtopic.php?p=8716018&highlight=#8716018

Video without narrative below

https://www.youtube.com/watch?v=5TYZChIdy14

 

[jimbote]

interesting links and video. One anecdote i'll add; years ago i was messing with my 1986 4runner that i had swapped in a turbo 22rte from another 4runner. Fun truck, and i was experimenting with different turbos to get one that had better boost characteristics. I ended up with a 1988 turbocoupe IHI unit. I disassembled the turbo to clean it up and reassembled it. What I didn't realize at the time was that it was missing the turbine side piston ring as this was the first turbocharger I had ever taken apart. The thing ran like hell and had instant boost but it's smoked like crazy. I quickly switched it out for a T3 unit off of a Chrysler 2.2 which was much laggier but didn't smoke. So I do believe the piston rings help with oil control.

On another note, the last time I had a vnt 15 apart I realized the plate that the VNT mechanism bolts to is a separate casting. In other words it can be removed and clocked then the turbo housing can be redrilled/tapped through the existing holes in that plate. So maybe reclocking the vnt15 won't be so difficult.

 

[AndyBees]

Jimbote, I had forgot about the info the guy from India posted (over two years ago). So, as soon as I can find the time, well, I am going to disassemble one of the VNT15s I have laying around.....

It would be awesome to put this issue behind us.

Also, I agree that the expansion ring seal is there to keep the oil in check. Otherwise, I see no benefit for it at all. And, it is obvious that oil gets to it, if not, something would seize in short order..

 

[oilhammer]

Anyone ever consider a remote mounted turbo? Like using one of the SOHC 2.0L engine exhaust manifolds with the single outlet (like the AVH or AZG) and fabricating a pipe to go to a turbo that is mounted down lower or wherever.

I always thought the 944 turbo had a neat setup. If anyone isn't familiar with them, they actually had the turbo mounted over on the intake. They ran the exhaust down into a collector, under the engine, then back up to the intake which was on the opposite side of the engine (crossflow). I know the ALH is not a crossflow head, but that really doesn't matter since the intercooler is going to necessitate the charge air path leave the engine manifold area anyway.

But the 944, like the naturally born diesel T3, has its engine laid down sort of on its side too. Not nearly as far, but they did package one big I-4 under the hood of the sleek 944.

I think the turbo is probably still best to be mounted down on/under the side of the block though in this application. And this would of course mean parting ways with the compact nature of the manifold/turbo combo.

 

[jimbote]

Anyone ever consider a remote mounted turbo? Like using one of the SOHC 2.0L engine exhaust manifolds with the single outlet (like the AVH or AZG) and fabricating a pipe to go to a turbo that is mounted down lower or wherever.
I always thought the 944 turbo had a neat setup. If anyone isn't familiar with them, they actually had the turbo mounted over on the intake. They ran the exhaust down into a collector, under the engine, then back up to the intake which was on the opposite side of the engine (crossflow). I know the ALH is not a crossflow head, but that really doesn't matter since the intercooler is going to necessitate the charge air path leave the engine manifold area anyway.
But the 944, like the naturally born diesel T3, has its engine laid down sort of on its side too. Not nearly as far, but they did package one big I-4 under the hood of the sleek 944.
I think the turbo is probably still best to be mounted down on/under the side of the block though in this application. And this would of course mean parting ways with the compact nature of the manifold/turbo combo.

interesting idea although it might increase lag as the relatively cooler diesel exhaust gasses cool further on their trip around. I remember the first 2.3 fox mustang turbo cars used a similar approach to turbo mounting, turbo was basically on the intake with a suck through carb and fed exhaust gas from the other side of the engine via downpipe that snaked all the way under the oil pan. Cool little cars

 

[oilhammer]

I agree the lag may be an issue, however, in the case of the Vanagon, you'll certainly be using lower gearing than what a Golf etc. would use, that will help some. Also, the charge air tract volume could be reduced by using an air-to-water type intercooler, and making use of the T3's vast cooling system capacity, which could reduce some lag even further. Given the engine placement, that type of charge air cooling seems better anyway.

It would seem using a relatively small VNT on it would still keep lag manageable. Not like so many of the older wastegated cars. My '84 Quantum TD was pretty laggy.... but once you were off the line and on boost, so long as you kept the gears rowing it was not so bad. And on the highway it was stellar, 70 mph was right at the sweet spot. I miss that car.