Oil Pump Question

[thehazard]

Hi there, I just have a question about why people don't seem to use fuel pumps for their turbo oil requirements? I can find many fuel pumps that deliver 40+ psi at the required gpm levels for much cheaper than the other pump alternatives. I have listed one such suitable fuel pump below and again was wondering what the problem with these are. If this pump is not suitable could I receive some direction or an example of what would be suitable for the oil requirements of a turbo?

255 lpm (1.06 gpm) at 43 psi Fuel Pump

Thank you for the time.

[racket]

The problem with using a fuel pump is the viscosity of the "fluid", they're made for free flowing fuel , lube oil on a cold day ain't free flowing unless you're using the type of oil more suitable for a ball bearing turbo .

You'll probably find the flow rate will be severely restricted compared to the pump specs , I have tried using a fuel pump with my ball bearing engines , but without success .

There are gearpumps available on Ebay that will do the job .

[richardm]

I have a similar fuel pump that i used for some tests with diesel fuel. It works ok but it has a pressure relief valve that kicks in and out since the flow output trough my nozzle is too small. That was just to say that I have some experience with this kind of pump.

My oil system uses one of those: www.aliexpress.com/item/1005004406800444.html?src=google&src=google&albch=shopping&acnt=272-267-0231&slnk=&plac=&mtctp=&albbt=Google_7_shopping&gclsrc=aw.ds&albagn=888888&ds_e_adid=&ds_e_matchtype=&ds_e_device=c&ds_e_network=x&ds_e_product_group_id=&ds_e_product_id=en1005004406800444&ds_e_product_merchant_id=109212433&ds_e_product_country=CA&ds_e_product_language=en&ds_e_product_channel=online&ds_e_product_store_id=&ds_url_v=2&albcp=20695954287&albag=&isSmbAutoCall=false&needSmbHouyi=false&gad_source=1&gclid=CjwKCAiAu9yqBhBmEiwAHTx5p6EE3kNiGMbHh72IXFhCpbGqt5SjwuvuF9NZGmWvcRGx9QrhTTMK2hoCiNcQAvD_BwE&aff_fcid=32f8d98d442e4dca910bbee029ede1ee-1700251770339-00877-UneMJZVf&aff_fsk=UneMJZVf&aff_platform=aaf&sk=UneMJZVf&aff_trace_key=32f8d98d442e4dca910bbee029ede1ee-1700251770339-00877-UneMJZVf&terminal_id=3f1738a79838467cbd532c9a39773af3&afSmartRedirect=y

It is inside the oil tank an driven by a 12 volts dc motor it draws about 120 watts at 55 psi plenty of flow. So if you happen to find a cheap motor the pump system can be quite low cost. From my experience using different motors you need a motor with a lot of torque at a rather low rpm. !000 is enough with that pump.

All this to say I doubt that the fuel pump will be adequate. Oil being much more visquous than fuel i think it will lack the required torque. Also remember that fuel travels trough the motoring such a fuel pump. Again oil is much thicker. Final note Your pump might eventually work with hot oil. Fuel pumps never pump hot fuel..

Finally 225 liters per minute does not equal 1.06 gallon per minute...Got to be one or the other.

[thehazard]

Thanks for the help of explaining the problems with fuel pumps.

Your suggestion Richard looks good (at quite a good price), but currently I want the simplicity of an electric oil pump and don't want to get into the complication of a separate oil pump and motor. Also I meant 255 lph as opposed to lpm (which converts roughly to 1.06 gpm).

As an alternative I have just found a gear oil pump that can deliver 3.2 GPM but doesn't list the psi, is it okay to use the pump I have listed below?

www.amazon.ca/YaeMarine-Scavenge-Reversible-Lubricants-Machinery/dp/B08THCFSPK/ref=asc_df_B08THCFSPK/?tag=googleshopc0c-20&linkCode=df0&hvadid=459396099097&hvpos=&hvnetw=g&hvrand=4236517481574368622&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9001394&hvtargid=pla-1362012010042&mcid=ec28f5c9e6ee339f9b8b7f46ed3b5820&th=1

[richardm]

Hi again!
I ve just had a look at that pump. I have no experience with it but I once considered such a pump. Here's why I did not go for it:
It is designed as a "scavenge pump" It's job is to suck out oil from a cavity and direct to a sump of some sort. Or it can be used to transfer oil from a container to another. So I'm very doubtful about its capacity to build enough pressure for your application. And if it does, beware of burning up the motor.
Have look at the comments and you ll see comments about its duty cycle. This means the motor gets hot and needs a rest period after a while, and that is at normal transfer use, no pressure involved.
There are also some comments about poor quality
And finally from my experience beware of those ratings they advertise. I ve found many ratings on different items to be grossly exaggerated.

I will post a photo of my oil system for you, just watch for a new post Sorry I don't know how to attach a picture to this answer.

[richardm]

A picture has been posted

[slittlewing]

The Marco UP oil pumps have been used on several engines, which are similar to the gear pump posted previously.

I used a Marco UP9 on my jetbike (there is a thread somewhere on here!) and it worked very well, with plenty of headroom and used PWM for pressure control. The Marco pumps are expensive so the eBay or Amazon copies should also do the job. As long as it has bronze gears, and is a gear type pump it should be fine. With that pump I could easily get 6 bar if I wanted to.

Duty cycle is not really an issue with us given the generally short engine runtimes and high fuel burn rate.

Cheers

Scott

[thehazard]

The pump is a gear type, but is made with copper as opposed to bronze. Is this a significant problem?

[richardm]

Have a look at those. In my opinion you better go with stuff that was designed for the job... Plenty of nice info too... Have a nice evening or morning depending of where you are on this big ball.
www.rbracing-rsr.com/oilsystems.htm

[racket]

Some nice units there , but too pricey for my budget :-)

I totally agree about using the right pump for the job , thats why I've stuck with my Subaru oilpump powered by a cheap 24V motor run on 12V , they're bullet proof and can easily run 70 psi all day long with hot oil and they have the oil filter and pressure relief valves as standard , flow ~9 lpm at ~1000 rpm

Cheers
John

[thehazard]

Alright, thanks for the help!

[slittlewing]

Nov 18, 2023 14:35:19 GMT -5 thehazard said:

The pump is a gear type, but is made with copper as opposed to bronze. Is this a significant problem?

No that should be fine. As long as the gears are metallic instead of plastic, so they don’t soften with hot oil.