I think this is a great experiment... looking forward to the pictures. Would I go to all this particular extra effort in this one area myself... probably not. Gonna enjoy learning from someone else's experience ? Absolutely !!
The after-run cool down cycle is pretty standard as a way to deal with heat soak... given how self-contained you are building this system you could easily add a simple timer circuit to run your oil cooling system for a few minutes after you shut down the engine. Or close the loop completely and have the after-run cooling cycle temperature controlled ?? Sounds like you have an oil temperature sensor in place already ?
I think this is a great experiment... looking forward to the pictures. Would I go to all this particular extra effort in this one area myself... probably not. Gonna enjoy learning from someone else's experience ? Absolutely !!
The after-run cool down cycle is pretty standard as a way to deal with heat soak... given how self-contained you are building this system you could easily add a simple timer circuit to run your oil cooling system for a few minutes after you shut down the engine. Or close the loop completely and have the after-run cooling cycle temperature controlled ?? Sounds like you have an oil temperature sensor in place already ?
Thanks Vincent for your supporting thoughts. Yes what I am doing is "experimenting". There may be other ways to achieve the same goal. An electric pre-lube (non continuous) pump plumbed to the engine oil piping somewhere is one I have read about. All I think my system provides over the former is the choice of a separate oil and cooler. It is also "non invasive". What I am doing is to disconnect the VW turbo oil supply line, plug it at the filter mount and set up the contraption that I was describing yesterday directly to the turbo. I don't expect my system to be perfect but rather that it will need to be fine tuned, modified etc.
Indeed I plan to wire a timer so that the turbo lubricating system will be running before the engine starts and after it has been shut down. I have not given this any attention yet .
Haybayian
Why not run a oil/water core? Some garretts are dual cooled. My IHI 5RHB in my old Thunderbird TurboCoupe was that. Far simpler, just need to run a tap off the coolant line to and from the turbo.
A good point.
Yes I am aware of the water cooled turbos. Improved cooling is a step in the right direction but does not address the "questions" that my post raised:
1)oiling the turbo's journals before the engine's oil pump kicks in and after it has stopped. And I was also suggesting that a separate system would allow the use of a different high speed bearing oil for the turbo only.
The bottom line is that no system is perfect. The system that I am suggesting is not complicated and not expensive...in the scale of the things that are discussed on this forum.
Haybayian
why use the same weight oil as in your engine when you don't have to? i would use the thinnest weight oil you can get that has good protection. maybe the elf 0w30 economy oil? the turbo will spool so much quicker with a thinner oil :wink:
good luck on your project!
Does the flowrate of oil to the turbo need to be varied according to the speed of the turbine? I'm thinking at engine idle when turbine is barely rotating will the excessive oil squirt out of bearings and into intake or exhaust? Or is this wrong thinking and the bearings free draining?
Does the flowrate of oil to the turbo need to be varied according to the speed of the turbine? I'm thinking at engine idle when turbine is barely rotating will the excessive oil squirt out of bearings and into intake or exhaust? Or is this wrong thinking and the bearings free draining?
I don't believe that high oil pressure at low turbine speed should have any particular effect on the bearings' seals. These seals must be designed to sustain a given oil pressure no matter the rotating speed. The Tilton electric pump is rated to produce a maximum of 60 psi which is a safe range considering the Garrett turbo is designed to handle a maximum of 70-80 psi in VWs.
If I am wrong , of course, I would like to know.
Haybayian