I am determined to build a little jet engine using a turbocharger. Have all of the theory side mostly worked out.... Just trying to source all the
bits I need before I order anything.... I need to get it all within my small budget..
At the moment I am having trouble finding a suitable oil pump for the hydrostatic turbo bearings.
It needs to deliver around 150PSI at 4GPM from a 12/24v battery. Obviously the oil will get hot during operation as they would in a turbocharged
car.
There are a couple of oil scavenger pumps with gear mechanisms for sale but they are knocking on £200.... which is pretty much my entire budget..
Can any of you clever chaps think of a cheaper way of getting the oil pressure I need? Or think of a good source of cheaper pumps?
Why do you need such high pressure? A turbo runs off engine pressure through a restrictor valve (metering jet), at about 3bar (43psi).
Cant you get a simple small capacity pump and use venturis or restrictors to increase pressure within the capabilities of the pump?
My younger brother has built one, i'm sure he used an oil pump off a ford motor, one that can be unbolted from the side of the block, and powered
it using a 12v battery drill, he used to start it with a leaf blower running on bbq gas, then changed over to kerosen once it was warmed up and
running. he's had a few fires come out the intake side, and the big fail was blowing off the compressor housing and in the process smashing the
compressor wheel to bits at some crazy high rpm!
Power steering pump perhaps?
Thats a fair observation, I based the requirements on the Garrett literature that states the pressure should be at 4.6bar max (70PSI) But assuming a
pump rated for 150psi at cold temps would be better suited to giving me 70psi when the oil thins at 150 degreesC
But your right, a more generic pump with a restrictor might work out cheaper..... Need something that can handle the temperatures. Hmmmm
I have a selespeed oil pump off an Alfa 156. You'll have to goofle it to see if its any good to you?
quote:
Originally posted by tegwin
Thats a fair observation, I based the requirements on the Garrett literature that states the pressure should be at 4.6bar max (70PSI) But assuming a pump rated for 150psi at cold temps would be better suited to giving me 70psi when the oil thins at 150 degreesC
But your right, a more generic pump with a restrictor might work out cheaper..... Need something that can handle the temperatures. Hmmmm
http://www.alfaworkshop.co.uk/images/51736315-790-1-800.jpg
http://www.alfaworkshop.co.uk/parts/Alfa_Selespeed_pump.shtml
Plenty on Ebay, as an example Toyota MR2 Turbo N/A Mk2 SW20 Power Steering Pump | eBay
Not the pressure you need but if you have a fat pipe to the bearing it should not matter as you will get lots of flow 
the oil gets very hot, you will need a good size oil cooler (100x300mm min), really important to keep the pump running a good few minutes after
running.
Oil pressure should be about 40psi above the boost level. ill be running nearly 35psi of boost on the schwitzer so 75psi isnt a bad ball park. As the
oil gets hots the flow increases massively, if the pump cant keep up the pressure drops scary quick.
All observations from running a home made GT 
Most of the electric oil pumps from Mocal, Tilton, etc. are re-badged Shurflo pumps.
The alpha pump is a low flow high pressure jobbie (55bar) so not quite what I need I think.
That MR2 pump is quite a crafty idea, although it is enormous for the needs of the turbo. IE uses a LOT of power.
I also found this: BUCHER HYDRAULIC GROUP 2 GEAR PUMP-FREE UK DELIVERY | eBay
Which if its span at 2000RPM I can get 2000PSI at 4GPM Really high pressure, but with a pressure relief valve... possible...
An engine oil pump might be an option as they are kinda designed for the job...
quote:
Originally posted by dinosaurjuice
the oil gets very hot, you will need a good size oil cooler (100x300mm min), really important to keep the pump running a good few minutes after running.
Oil pressure should be about 40psi above the boost level. ill be running nearly 35psi of boost on the schwitzer so 75psi isnt a bad ball park. As the oil gets hots the flow increases massively, if the pump cant keep up the pressure drops scary quick.
All observations from running a home made GT
4 gpm ? What size of turbo do you have.
Why not use a rising rate fuel pressure regulator for the oil? That would give you (if you use a renault 21 one!) 3bar above boost. Not sure how you
would drive it though, as you dont have an inlet chamber per-se.
[Edited on 7-2-12 by MakeEverything]
Could use an air bleed off the compressor before it goes into the combustor.... Was planning on doing this anyway to drive some small actuators on the intake.... Will have a look... Although not sure how well fuel handling pumps/valves will handle warm oil.,
quote:
Originally posted by tegwin
quote:
Originally posted by dinosaurjuice
the oil gets very hot, you will need a good size oil cooler (100x300mm min), really important to keep the pump running a good few minutes after running.
Oil pressure should be about 40psi above the boost level. ill be running nearly 35psi of boost on the schwitzer so 75psi isnt a bad ball park. As the oil gets hots the flow increases massively, if the pump cant keep up the pressure drops scary quick.
All observations from running a home made GT
What pump are you using?