Turbo Options - ALH

I am finishing up a ALH conversion into an old Vanagon which has been tilted over at about 53 degrees. Unfortunately, even though the oil drain from the turbo is about 3 inches higher than the oil in the pan I am getting oil through the turbine wheel at idle.

Right now I am using a BHW turbo GT1749VA. See a pic of setup below.



I wanted to bounce a few ideas of the great minds at TDIclub. Right now I see I have a few options

1) Scavenge pump to push oil back to sump (Not willing to take the reliability hit. Most pumps seem unreliable)
2) Custom turbo manifold
3) Different turbo that moves cartridge up higher on motor
4)I've heard of some routing the oil drain line close to the oil pickup in the sump, to use the suction of the oil pump. Any experiences with this?
5) Restrict oil flow to turbo. I understand this is usually for ball bearing turbos but some suggest it for VNT? I am using a -4AN line from the oil filter housing

If I am looking at option 2 or 3 I will be upgrading to a bigger turbo since im doing the work. Might as well get something from all the extra work looking at something in the ballpark of 300-ftlb crank as im clutch limited

Any suggestions on a turbo? I was thinking something close to VNT17 size but looking to get a newer generation VNT. Possibly GTC1549VZ? I may have access to a deal on a GT1749VC, which I understand is a newer gen design even though it doesnt have the GTB/GTC prefix.

Any input is greatly appreciated

put oil drain into the pan like on 1.8t motors
your oil drain from the turbo is nearly going horizontal, where it needs a lot of drop
also, put the CCV into the intake, after the MAF. you will have a slight vacuum from the restriction of the filter, this helps to draw the oil "in" away from the turbo 'piston ring' seals

all else fails, some have used the engine mounted vacuum pump as a scavenge pump
then you just use normal electric hella vacuum pump for the brakes and such, source from passats (and many many many other newer cars) in the junkyard

ETA: never restrict oil to journal bearing turbo, bearing failure is the only result of this

Thanks 486, btw love your builds. Has to be some of the most creative stuff ive seen on here.

The drain bung is already very similar to a 1.8T setup. I could move it down maybe an inch but it wouldn't change the oil height in the line (as there is some oil in line with engine off)

I think the biggest issue I have is even though there is 2-3" of vertical, with the longitudinal turbo there is about 6" of horizontal I need to make, which gives much less than 45deg to run the oil.

Could you tell me a bit more about using the vacuum pump for scavenging?

Heres a better pic of the oil drain.


Im pretty close here to just picking up a VNT17 and calling it done.

As I mentioned earlier I am clutch limited to ~300ft-lb so that might influence the turbo decision. I was actually thinking of adding newer style BB turbo, something like a GTD1756VRK from one of the European vendors. Would this be too much turbo if I want to limit to 300 ft-lb? Would still like a good spool and a very strong mid-range

Obviously, my first preference would be getting this damn GT1749VA to drain somehow.

Heres another photo showing the oil drain a bit better

I would ask the supplier how their manifold is oriented for the GTD1752/6 before purchasing in case it sits the same way? It does have an extra long snout on the turbine exit so your downpipe would definitely need some reworking. Either turbo could be limited in the tune to keep your clutch happy though.

Cool build!

CakeD said:

Thanks 486, btw love your builds. Has to be some of the most creative stuff ive seen on here.
The drain bung is already very similar to a 1.8T setup. I could move it down maybe an inch but it wouldn't change the oil height in the line (as there is some oil in line with engine off)
I think the biggest issue I have is even though there is 2-3" of vertical, with the longitudinal turbo there is about 6" of horizontal I need to make, which gives much less than 45deg to run the oil.

Click to expand...

Thanks, man.

I was picturing you using the hole in the block for the drain, thus my suggestion of putting it in the pan
the thing about the turbo drain is that it can be under the level of the oil, as you've got air flowing in through the gap in the seals (both exhaust and intake) meaning that so long as your crankcase pressure is not significantly higher than either exhaust pressure (pre-turbine) or intake vacuum (post compressor) it'll drain down as it should

the problem comes from when people run a road draft tube for crankcase venting and a very free flowing exhaust (or a turbo that isn't making any pressure at idle in the case of oil into the intake) then your engine will try breathing through the gap in the turbo seal ring, carrying oil out with the CCV gasses

on the scavenge pump, I forget who it was but someone on here had a very neat little can that bolted to the bottom of the turbo, maybe 4cm diameter and 4cm high, does not need much volume. Then you have a diptube from the bottom that goes to a smaller diameter vacuum line up to the vacuum pump. IIRC 11/32" line fits the nipple on the vac pump very well.
You need it to actually suck the oil up the tube rather than if you used a normal -10 drain line up to the vacuum pump it'd just gurgle the gasses up to the pump leaving the oil down in the line at the turbo.

Oh and I'm a very big fan of larger turbos than most would consider.

Your clutch and gearbox are only good for 300 ft/lb, but you don't need to make that figure at 1800 rpm (which is only 100hp)
bump up a size or two and get it breathing efficiently enough to make 300 ft/lb at 5000 rpm and you're making 280hp with the exact same amount of strain on all of the (rather hard to source nowadays) driveline parts.

If you do size your turbo for operation throughout the upper rev range you will be moving enough air lower in the powerband to make gearbox splitting amounts of torque. Torque is what breaks parts after all.
You want to limit torque in the tune of course, because that's the beauty of an electronically governed diesel, you can just limit fuel at a set torque value rather than the old mechanical governor standby of "well, the last one blew up at 20 psi of boost so we'll wastegate it at 18 psi and the remainder of the fuel past that will just make black smoke"

No unfortunately, the OEM drain hole was about level with the turbo drain at the tilt. I do think I could potentially run a tee to this location from the drain to allow CCV pressure on both sides of the oil. Should help with the problem you described.

I shot an email to Owain at Malone tuning asking his opinion on the GTD turbos and tuning. Im no turbo guru, but I feel like going with slightly larger turbo (GTD1756VRK over GTD1752VRK) should lower required boost, EGT/IAT and overall stress on the motor, assuming the right tune. Not going to run either turbo at its max capacity as I want to retain motor longevity but the lower IAT the better. I feel around 200hp and 300ft-lb wouldn't strain these turbos too much

I did end plumbing in a nice water/air intercooler setup that should help keep everything cool as well