First post, first attempt at building a turbo jet.

[racket]

Hi Rob

Is the pump making strange noises ??

Cheers
John

[finiteparts]

Just a thought...I would try to test the pump and a variable restriction (valve) by themselves, with a pressure gauge inline. If that goes ok, add a part, then add another.

Remember, vane and gear pumps are volumetric machines. They will push whatever the captured volume of oil (between teeth or vanes) through whatever hole they have too by jacking up the pressure till they pop the relief valve, which typically are set to over 1000 psi (~ 1200 psi). Some also have flow control valves built in that control the flow rate vs pressure, so that when you have more pressure assist at lower speeds that when you are at highway speed, via a controlled orifice and bypass. Using a PS pump verses a oil pump changes a few things.

Good luck,

Chris

[racket]

Hi Rob

OH , just realised you are running a PS pump ( thanks Chris ) , they can give problems due to the internals , they often need modification for our use .

Cheers
John

[sputnik]

Ah ok, thanks guys.

I actually hadn't considered it could be a side effect of using a PS pump.
I think, as you've both pointed out the way forward is probably to give it a go with a simple loop to rule out any pump issues and go from there.

Is there a tried and tested method for modifying PS pumps should that be the issue or is it a case of take it apart and see what I find?

Thanks again!

Rob

[finiteparts]

Hey Rob,

I do not have any specific advice other than the previously mentioned process of testing one component at a time.

I would watch the peak pressure output, as really high pressures can be problematic, as the bearing stiffness will be affected. For example, Holset limits the HT60s to 58 psia inlet pressure when the turbo is warm and at full load, it can got to 88 psia on cold startup. Since the bearing stiffness and the squeeze film in the full floating hydrodynamic bearings are set by the oil conditions and flow, going to high pressures can drastically change the rotordynamics (i.e. stiffer bearing film and damper films) and move the rotor modes into the operating range.

The variable valves in some of them make the outlet pressure vary over the operating speeds and you may want to remove it. The oil restriction of the turbo oil feed lines should be sufficient to set the system back-pressure and perhaps use a valved, bypass line from the pressurized feed to control the system pressure. Remember, they are volumetric machines, so it will for the swept volume of oil through the system, every revolution, at whatever pressure it takes. The pressure it takes is set by the restriction that it sees downstream, i.e., the bypass valve open area and the turbo's bearing systems area.

Good luck,

Chris

[finiteparts]

Also, you should check the flow rate.  The HT60 is just a touch larger (80mm vs your 76mm), but here is Holsets recommendation for their turbos...


"14. Recommended oil flows for the turbochargers are 3 litre/min at idle and 3.5 - 4.5 litre/min above maximum torque speed."

Good luck,

Chris

[sputnik]

Hi guys,



Thanks for the help Chris and John!

So after a bit of a break from the project I'm back at it. I think the issues I'm having are definitely down to the pump. I've tried it in various configurations all the way down to a simple draw and return from a reservoir and in its standard form it oscillates severely. With the little valve removed (see below images) it pumps a smooth flow of oil but at a pathetic pace and pressure so I think that this pump is for the bin really as its going to take more time and effort than its worth to make it work. With that in mind does anyone know of a readily available pump (in the UK) that I can use in conjunction with my (24v running on 12v) scooter motor that John recommended?







Also Chris I think my original design is as you've described with a valved bypass line from the feed to the turbo.  The oil pressure gauge 'T' is located at the oil feed port at the turbo core itself so providing I can get the pump issues resolved I should theoretically be able to use the bypass and gauge to control the pressure to the turbo adequately.  Below is an illustration of my oil system routing.  As for the oil flow rate that's going to have to be eyeballed really at this point I think as I have no way of accurately measuring that.




Thanks again for any help guys, I've never messed with pumps before so this part of the project is all new to me so if im missing the point feel free to let me know haha!

[slittlewing]

I would avoid the complication of trying to marry a pump to your motor at this point, and just buy a Marco up9.
Cheaper Chinese copies are also available that would probably do the trick.

www.ebay.co.uk/itm/175776514426?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=CLYh5ateSzu&sssrc=4429486&ssuid=2RSzGBVyTz6&var=&widget_ver=artemis&media=COPY

Cheers

Scott

[sputnik]

Yeah cheers Scott, I've bought a mid range cheapo. I'll see how that goes when it arrives