Garrett & Holset Turbo Users - Your Oil Drain May Be Too Small!

[1SloColt]

The truth is if you're firing 80psi of high-volume oil pressure into one of these turbos

This is the problem. A small oil drain obviously will not make this matter better. Its the high volume that kills turbos, and you obviously need a drain tube ID that corresponds to the amount of oil being sent at such a high volume/pressure. An .080" restrictor in a -4an feed line is necessary off the oil filter housing, although I have seen standard bearing turbos successfully run a straight -4an feed line for a sustained period of time without issues. I would even try down to a .060" restrictor just to keep volume down. A 1/2" ID drain for a .060" restrictor in a -4an feed line should work just fine. -3an wouldn't be a bad route either. In any of these cases I would advocate a minimum 1/2" ID drain line be utilized. I have been running a precision SCM cartridge turbo for 3 years with a .076" restrictor in a -4an feed off the filter housing on a -10an return line. These cartridges are known for taking a dump due to too much oil pressure/volume. I've yet to see that problem with my oil feed/drain setup.

 

[Artago]

Iv always wondered if poor crank case breathing could also worsen it by pressuring the crank case.

Me too, any thoughts/input Justin?

Tom

 

[JusMX141]

Well absolutely. Anytime your crankcase is seeing excessive pressure, the gravity-flow from the turbo will not drain properly....especially if your drain tube is too small.

Seriously I'm thinking of fabbing my own custom oil drain using a 1" pipe with a small piece of hose in the center for my AWD's HX40 when the time comes. I'll cut my own flanges, and use a non-turbo oil pan so I can fab my own fitting at the pan to get around the small hole and close bolt spread on the turbo oil pan's flange.

 

[myturbo]

i love this thread .im just got all my inlet and drain tubing and fittings flanges. im gonna chang them all now .since my turbo was in the upper 1500 dollar range.


has there been any problem with the inlet hese .and a problem with the inlet fitting holes being so small

 

[Artago]

Well absolutely. Anytime your crankcase is seeing excessive pressure, the gravity-flow from the turbo will not drain properly....especially if your drain tube is too small.

This is kind of off topic, but how do I check for excessive crankcase pressure and how to relieve it. I have my VC port and PVC routed through a filter back into the intake. Is that sufficient? Do you know of any good threads I should read on the topic or do you have some advice for me?

Tom

PS: Once again, sorry about getting off topic.

 

[JusMX141]

It's still on the topic of proper oil drainage, so I don't see a problem.

On all of my cars, I've removed the PCV altogether and replaced it with the 5/16" hose nipple (1/8" NPT) from the intake manifold where the PCV normally connects. In it's place, I use a hex-head 1/8" NPT pipe plug to cap off the intake manifold. I run both lines to a catch can with a drain on the bottom and a breather on top.

Some will insist that this isn't the way to go, but I've done it for years with no ill-effects. The crankcase can vent to atmosphere with no worries of excessive crankcase pressure causing poor turbo oil drainage. This is illegal in the eyes of some state emissions inspections, so use caution if you choose to go this route....but with no PCV and no EGR, you won't believe how clean your intake manifold runners will stay.

 

[Artago]

It's still on the topic of proper oil drainage, so I don't see a problem.

On all of my cars, I've removed the PCV altogether and replaced it with the 5/16" hose nipple (1/8" NPT) from the intake manifold where the PCV normally connects. In it's place, I use a hex-head 1/8" NPT pipe plug to cap off the intake manifold. I run both lines to a catch can with a drain on the bottom and a breather on top.

Some will insist that this isn't the way to go, but I've done it for years with no ill-effects. The crankcase can vent to atmosphere with no worries of excessive crankcase pressure causing poor turbo oil drainage. This is illegal in the eyes of some state emissions inspections, so use caution if you choose to go this route....but with no PCV and no EGR, you won't believe how clean your intake manifold runners will stay.

That's actually the same setup I've been running. Intake Manifold PCV port plugged and the PCV and VC breather run to a filter / catch can then back into the intake. No EGR as well, and FIAV block off.

Back to the oil drain issue. We've spoken (via PM) about how I killed a V-Trim within 1500 miles and my 57 Trim is already got shaft play after 1000 miles. Well, if what you have to say is true about the oil drain then I know why I blew both my turbos. When I installed the oil drain line it didn't want to mate perfectly and had a bit of a fitment issue. It was only 1/2 - 1" off so I just forced it to line up. It all looked good but when I came back to it after several thousand mile the oil drain line developed a significant kink (probably from heat flex). This kink was surely causing a restriction and is probably what killed the turbos. I have since replaced it with a kink-less line. I hope that it solves my serial turbo killing issue. I'll let you know after I rebuild my 57 trim and drive it for 2000 miles.

Tomas

 

[Sp1kE]

Information taken direct from the Holset service manual for the HX35/40:
To ensure oil drains into the engine under all operating conditions, the return connection into the engine sump must not be submerged and the outlet flange of the turbocharger must be 50 mm above the maximum oil level of the engine sump pan.

Is this not a big problem too?
My buddy turboing his car has his return line tapped into the block. I asked him why the hell he did that. He said turbo's are not suppose to have their return lines submerged...?

Our returns are at the lowest spot on the oil pan are they not?

I think that would be a big factor, no matter how big you make that return line, you are still going to have to push the all the weight of the oil in the pan using the stock return location.

 

[myturbo]

Is this not a big problem too?
My buddy turboing his car has his return line tapped into the block. I asked him why the hell he did that. He said turbo's are not suppose to have their return lines submerged...?

Our returns are at the lowest spot on the oil pan are they not?

I think that would be a big factor, no matter how big you make that return line, you are still going to have to push the all the weight of the oil in the pan using the stock return location.

very good point . we do have a few places on the block for a return

 

[grantman10]

Ok, then what about the garrett bb center sections? I have a GT3076r bolt on and was thinking about getting a 10an return kit consisting of probably those same restrictive AN adapter fittings to complete my oil lines.

Then I read this thread and though I may be better off welding a 12an(19mm) fitting to the pan. But when I measured the oil drain outlet on the Garrett center section it was ~15mm, which would work fine with 10an line, but the adapters are not .625" inside diameter as shown above by jusmx141...

And on top of all that the oil return line is submerged anyway. I want to make sure this turbo has a long life! What to do?

 

[JusMX141]

Our returns are at the lowest spot on the oil pan are they not?

Actually, they're not. They dump at the highest point of the pan.

Ok, then what about the garrett bb center sections?

Ball bearing turbos have such little oil supplied to them that drainage should never be an issue. From the head with a tiny .030" oil restrictor is the recommended oil source.

 

[need2boostpsi]

my extreme psi oil drain setup is the same size as my holset drain hole, I rechecked today and I'll post pictures tonight

 

[need2boostpsi]

uploaded as promise

 

[bluegs03]

did you get the 10an oil drain setup from extreme?

 

[need2boostpsi]

yep push lock 10-an for holsets

 

[nfernotalon]

yep push lock 10-an for holsets

Cant find that one, you have the link?

 

[JusMX141]

That's just horrible. According to Holset the entire drain pipe should never get smaller than about the outermost ring of the drain hole in this picture:

Something needs to be done. I'm starting to think this is the main reason that filter-housing-fed turbos are dying prematurely when supplied with no restrictor.

 

[bluegs03]

Ok so now that we have identified a problem is there any solution besides make our own? How have others who have 1000's of miles on their holset turbo setup gotten by without blowing their turbos? This isnt happening to every single holset installed on a dsm...

 

[Supa Dexta]

Are you guys sure you don't have any kinks at all in you're returns? Not a full on kink, but even squished a bit? Cause it will cut flow quite a bit. I just got an NT pan and had a -10 welded to it.

 

[JusMX141]

This isnt happening to every single holset installed on a dsm...

Correct, but not everyone is sourcing their turbo from the filter housing and shoving 100psi of oil pressure into it at wide-open throttle. I'm simply trying to get to the bottom of the excessive pressure / insufficient drain issue that seems to plague some DSMers on a repeat basis.

 

[gstryyder]

guess i will be having my own ginormous custom line made. especially ### i am gonna need a longer one anyways. just hope that one of the vendors will be able to help out and maybe get something rolling on some giant AN fittings and lines.

 

[dsm-onster]

I agree. I'm going to take the flange off my oem garrett drain line (from my old turbo ford) that I was using, widen it with a mini grinder and weld on some larger piping.

One HUGE problem. The inlet hole on the stock mitsu oil pan is no bigger than any of these drain flanges that are too small. There's no point in widening the drain flange and piping only to have a smaller hole at the pan inlet.

 

[Artago]

Correct, but not everyone is sourcing their turbo from the filter housing and shoving 100psi of oil pressure into it at wide-open throttle. I'm simply trying to get to the bottom of the excessive pressure / insufficient drain issue that seems to plague some DSMers on a repeat basis.

I was I had a kink in my return line and had around 80 PSI at 3000 RPM cruise and WELL over 100 PSI at WOT.

Tom

 

[need2boostpsi]

I have had my turbo on feed from the head and a kinked oil return line for 2000 miles and the turbo has zero shaft play and zero oil blow by, I think the problem is no two DSM's have the same oil pressure, and most are over feeding the turbo with too much pressure. I think if you had a problem with flow on the drain pipe you would be seeing some oil pushed into the turbine housing. also remember that if you over fill your oil or fill it to the fill mark 75% of the time the oil drain is under the oil level.

 

[JusMX141]

One HUGE problem. The inlet hole on the stock mitsu oil pan is no bigger than any of these drain flanges that are too small. There's no point in widening the drain flange and piping only to have a smaller hole at the pan inlet.

Totally true, which is why I want to track down a nice non-turbo oil pan to solve this issue. I'll use the stock oil drain location, but I'll make the hole in the pan as big as I can without the worry of keeping the pipe between the two bolt holes enough to get a bolt in it and a wrench on the bolt.