Oil Control Issues

[userscott]

I wondered if I could tap into the hive mind to help me resolve some issues with my HX55 - build thread here jetandturbineowners.proboards.com/thread/1192/hx55w-first-jet-rail-kart . 

I'm currently building a HX55 powered rail trolley and have had massive issues with my ZF steering pump. It delivers 8.5 LPM at 45 PSI and the second I pipe it into the turbo, the pressure goes through the roof upto 150+ PSI as the turbo is limited to 4.5 lpm. I have made some changes to the oil pump following discussions in my build thread - notably drilling out the flow restrictor and lowering the spring force in the bypass but it still doesn't behave particularly well. I think part of the issue is simply that it's a rotary vane type pump and so it just loves making huge PSI!


Inside the ZF pump..


General arrangement of the system, showing a Volvo S80 (ZF) power steering pump mated to a Parvalux DC Motor (A50-3096B). This is a 12V, 3600 RPM, 110 Watt DC motor. The controller is a 4QD Porter 10 wired with 6 mm cables which gives me a lovely range of power.

The specifications for the HX55 are 3.5/4.5 lpm, maximum oil pressure of 58 lbf/in2, oil temp of 95+/-5°C (203+/-9° F). (http://caboturbo.nl/wp/wp-content/uploads/2012/03/HX50-52-55-Workhop-manual.pdf Page 7)

This puts me into thinking the Marco UP12 is the correct pump to replace my setup. This gives me 3 bar (43.5 lbf/in2) of pressure, 6 lpm of flow (ø12 mm pipe) with a 180 watt motor. (https://items.marco.it/en/up12-oil-gear-pump-for-lubricating-oil.html) It seems to fit the bill, but I see reference to UP9 and UP6 used equally as much on the forum - so wondering whether I'm missing something with this option. I've made an assumption that I reduce the LPM adequately simply by reducing the pump speed with the PWM controller, something which seems to have little to no effect on my current ZF system!

Does anybody have a view on the suitability of the UP12 for this application?

[slittlewing]

We have almost identical turbos (hx50 vs hx55) and I can confirm the up9 is man enough for the job. I have had it produce >4 bar with very thin (yet hot) aero shell turbine oil.
This winter I switched to 10w60 oil and the pressure with cold oil has gone through the roof, so much so that I am using less than 50% PWM to get 6 bar.

In any case you only need the oil pressure to be 1 bar above P2 and you can vary your oil type and temperature if you run out of headroom (don’t think you will with a up9)

[userscott]

Thanks for your response - really appreciated.

Comparing the specs, the UP9 would give me 12 lpm at 5 bar which seems (to my uneducated guesses) less ideal (too high performance) than the UP12 for this application? My understanding of the UP12 is it’s a heavy duty slow and steady unit - and the price difference is nil.

The UP12 seems weirdly low spec compared to their other pumps - but then it seems to be the biggest, heaviest and so I’m thinking it’s a big “plodder”....

UP12:

items.marco.it/en/up12-oil-gear-pump-for-lubricating-oil.html

UP9:

items.marco.it/en/up9-heavy-duty-pump-12-l-min.html