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Turbo Oil Return...non-930 specific

I didn't want to clog up the turbo oil return thread, so I am starting this. The purpose is to examine the turbo return setups we use to get oil back to the crankcase or tank, whichever. In my case, I have an SC, originally retrofit with a BAE kit, now using 930 exhaust system. The old Rajay turbo sat much higher relative to the drain, which is in the left chain cover. Following photo is the current install. Drain outlet at the turbo is barely above the drain hole in the cover. There is no gravity drain.



The problem encountered is inadequate drainage from the turbo. This has been a problem since I first did the install. Muffler fills with oil, it leaks, etc.

In this current configuration, I drain into an AN-10 to a gear pump similar to a VW oil pump with an electric motor. Spec flow for this pump is 2.0 GPM (Electric Oil Feed and Scavenge Pumps).

I have previously determined the flow rate through the turbo to be 0.285 GPM. Oil was delivered to the turbo via an AN-4 oil line, unrestricted That test was conducted with the engine idiling, oil a bit warm, and pump inlet disconnected. I basically let the oil flow into a calibrated pitcher and timed it. On the surface, the little pump should have no trouble keeping up with this flow. BUT, it does. The muffler floods, car smokes.

Today, I went out and did the following setup to test the pump:



I am simply running oil through the pump. Oil temperature is about 38F. This setup, flowing through 3/8 barbs, results in a flow rate of 0.417 GPM. Not quite the 2.0 GPM advertised, but still more than the flow out of the turbo. So, this should work. BUT, it doesn't.

Next test is to go back out and try and standardize the oil temperature variances, to reduce any viscosity difference. Also, I will try and flow a known quantity of oil back into the chain cover through the pump, to check for restrictions. Lastly, I will try and flow oil back into the system with the engine running, to see the effects of crankcase pressure on the oil return.

I do recall the chain cover hole has a pretty clear shot back into the case, so I think there is a physical restriction. I do think the crankcase pressure may be part of this. Also, the flow into the turbo is excessive, I think. Hard to tell what the flow sj=hould be, because BW is not very forthcoming with technical support. I used to run a valve on the inlet to the turbo to tweak the flow. You can see the return to the cover in this last photo.


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Patrick E. Keefe
78 SC
Old 11-20-2014, 09:12 AM
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Your pump looks similar to my original pump that I got from eBay.
The one I had flowed OK but was way too noisy so after some research I purchased a Turboerx unit that's so much quieter and has enough flow for a dual turbo setup apparently.

'Whether the application moves 1 oz of oil a minute or up to 1.75 gallons a minute, 'under-flow' applications are no problem. In fact, the TurboWerx pump may be run dry indefinitely. May be operated up to 60PSI pressure.'

Base-Model Pump

Note sure how this compares you your pump but I've had no issues at all with my setup feeding to the sump plate.
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1980 SC Flatnose, Euro 3.0, LW Flywheel, 993 Cams, Port & Polish Heads, RS Cut Valves, Magnacor Leads, Boxster Brakes, WEVO Mounts, TRG Roll Bars, Rollcage, RSR rear fenders, WEVO Shifter, K27 7200 Turbo, OBX Headers, Tial Wastegate, Omex 710 ECU, 3.2 Intake, Full Bay Intercooler.....400HP
Old 11-20-2014, 09:49 AM
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Gavin, do you know what the oil delivery rate is for your turbo? What size line do you run to it, and do you have any restrictors in the line?
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Old 11-20-2014, 03:15 PM
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Have you checked the voltage or current draw at the pump with and without the engine running to make sure it's adequate for optimal pump performance?
Is it possible the turbo seals have failed prematurely?
Is this a journal bearing or BB turbo?
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Old 11-20-2014, 04:08 PM
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Steve, this is a chronic problem. Turbo seals are OK, I am sure. This is a sleeve bearing model BW. I will check the pump tomorrow though; good idea. I am a bit limited since I just had elbow surgery a few weeks ago, and I HAVE to take it easy or I'll rip my tendons loose.

I really think the issue is lack of pitch to the drain. Oil comes out of these turbos like foam. They really don't like to drain without pitch, and the more vertical, the better. My test stand has 24" vertical tube from the turbo outlet to it's pump, and has no issues. I'm working on a new catch can at the moment, along with a new crankcase ventilation system.

I'm still trying to find the requirements for oiling flow rate. I think it is around what I have now, so I'm hesitant to restrict the flow much further. My current smallest restriction in the feed line is 3/16", which is AN-3.
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Old 11-20-2014, 04:44 PM
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Move it to the sump plate. That'll give you more angle downhill.
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Old 11-20-2014, 05:19 PM
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Quote:
Originally Posted by Tippy View Post
Move it to the sump plate. That'll give you more angle downhill.
It's also on the list for the next week or so, as soon as I can weld up a fitting on one of the plates I have.
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Old 11-20-2014, 05:46 PM
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Do you have a check ball in the fitting at the oil pressure switch were you pickup your feed to the turbo? Is your issue mainly heavy smoke at start up, or later while running?
Old 11-21-2014, 06:52 AM
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I have a KKK 3LDZ and an oil line from Turbokraft which is for KKK turbos and has the check ball bearing setup :

TurboKraft Inc : Turbocharger Oil Feed Line Set : 3K-Warner [930 CVS BWK TK] - $205.00

Found some oil flow vids on youtube :

https://www.youtube.com/watch?v=qHjjtUq8dEU
https://www.youtube.com/watch?v=29cJiS4m-Lg
https://www.youtube.com/watch?v=HPjW0JBob7k
https://www.youtube.com/watch?v=zOEzvfp1o80 This one shows flow at several RPM's
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1980 SC Flatnose, Euro 3.0, LW Flywheel, 993 Cams, Port & Polish Heads, RS Cut Valves, Magnacor Leads, Boxster Brakes, WEVO Mounts, TRG Roll Bars, Rollcage, RSR rear fenders, WEVO Shifter, K27 7200 Turbo, OBX Headers, Tial Wastegate, Omex 710 ECU, 3.2 Intake, Full Bay Intercooler.....400HP

Last edited by gavinc69; 11-21-2014 at 09:36 AM..
Old 11-21-2014, 09:34 AM
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Pat, whats the cooler for under the rear funder just above your oil pump?
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1980 SC Flatnose, Euro 3.0, LW Flywheel, 993 Cams, Port & Polish Heads, RS Cut Valves, Magnacor Leads, Boxster Brakes, WEVO Mounts, TRG Roll Bars, Rollcage, RSR rear fenders, WEVO Shifter, K27 7200 Turbo, OBX Headers, Tial Wastegate, Omex 710 ECU, 3.2 Intake, Full Bay Intercooler.....400HP
Old 11-21-2014, 09:53 AM
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Cooler is for oil return cooling between the scavenge pump and turbo. I don't really need it 95% of the time. It helps at the track.

H2, no check ball in the feed circuit. The smoke is a symptom, at start up and across the rev range.

I have a sleeve bearing turbo; different requirements than a ball bearing turbo. I appreciate the vids, but it doesn't really help to quantify flow rates by looking at the oil pouring out of a turbo. kind of like guessing the air pressure in a tire by looking.

What i need to determine is: does my pump pump more or less on a time rate basis than I can deliver to the turbo? And, if not, why?
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Old 11-21-2014, 12:00 PM
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Pat-
I understand your problems. My installations on 911s have always used custom exhaust which located the turbo higher and draining to the chain cover was always adequate. One twin install went to a valve cover the other to the chain cover. I never use a turbo oil inlet restriction, nor would I recommend them.
I suspect your problems will be eliminated when you go to the center drain plate. There is no better dry sump pump than that location
If you wish to try one more option, the drain from the turbo can be improved by adding a small air vent. I saw a picture of this on a custom twin install on another thread. It was misunderstood as a backup drain, it was an air vent. Years ago we added air vents to turbos not having carbon seals on the compressor . This allowed operation under full pull thru intake vacuum and no seal leaks.
Old 11-21-2014, 01:13 PM
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Since I just had a helper available, we did another quick test:
Change the drain piping from the AN-8 existing to a barb fitting 1/2" ID hose. The AN-8 to 1/2 MPT fitting on the turbo outlet is just about 13/32" ID, which doesn't seem like much. This increase is enought to get the flow to stabilize and not smoke or leak.

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Old 11-21-2014, 01:22 PM
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