Fuel Pump Problems

[cebaero]

Hello everyone

I have recently conducted my first test of my liquid fuel system. I have a 12v 9a lawn mower battery hooked up to a PWM which then goes to a knock off bosch 044 fuel pump. At full power, I am only getting about 75psi. I have my gauge right outside my FT end cap so I know this number should be pretty accurate. After reading some other threads on this forum, it seems that others have been able to pull off much higher pressures with an o44 pump. Is there something wrong with my set up? I was hoping to get around 200psi, maybe even 250psi if possible. 

Or am I going to have to switch to an oil burner pump/motor to get my desired pressure?

Thanks

[richardm]

From my experience most automobile fuel pump using injection top off a t around 70 - 75 psi. They also have an internal pressure safety valve set a bit over that. You'll never get 200-250 from such a pump
Im using a modified oil burner pump that is driven by a 24 volts reverse osmosis pump motor It draws only about 60 watts and the pump puts out about 275- 300 psi but i added a safety valve set at 250 psi

Such a pump must be modified because they have an internal pressure regulator and safety bypasss normally set at around 100 psi. Some also have a clean cut in cut out system ( sometimes a solenoid valve) that has to be bypassed

[cebaero]

Aug 15, 2024 8:33:53 GMT -5 richardm said:

From my experience most automobile fuel pump using injection top off a t around 70 - 75 psi. They also have an internal pressure safety valve set a bit over that. You'll never get 200-250 from such a pump
Im using a modified oil burner pump that is driven by a 24 volts reverse osmosis pump motor It draws only about 60 watts and the pump puts out about 275- 300 psi but i added a safety valve set at 250 psi

Such a pump must be modified because they have an internal pressure regulator and safety bypasss normally set at around 100 psi. Some also have a clean cut in cut out system ( sometimes a solenoid valve) that has to be bypassed

Thank you

What kind of battery do you use for that?

Also, I am seeing oil pumps on amazon that will go up to 200psi, but only about 3gph. I need preferably up to 8. Would I be able to bypass this too?

[miuge]

We used a 044 knock off pump with a small 12V battery and it was able to maintain around 9bar/130psi pressure, however voltage dropped to below 11V when both oil and fuel pump were running:
www.youtube.com/watch?v=HbJ83cLt2Ys
With a proper power supply and around 14V these are able to go past 10bar/145psi.

[slittlewing]

I have both sytec copies of an 044, and real Bosch 044 motorsport pumps. Both can deliver 10bar pressure at 12V. You need a good battery.

There are many variants of pump that look similar to an 044 but don’t have the high pressure internals (therefore are made to deliver 3-5bar). The high pressure 044s have an M18 threaded inlet with steel helicoil.

Cheers

Scott

[richardm]

What kind of battery do you use for that?

Also, I am seeing oil pumps on amazon that will go up to 200psi, but only about 3gph. I need preferably up to 8. Would I be able to bypass this too?


My system is based on 12 volts but I use buck voltage converter to get 24 volts where needed

Be aware that oil is much more viscous than fuel and you might not get full pressure from a pump designed for oil

Some guys have used small hydraulic pumps I guess it all depends on the gaskets and seal compatibility with fuel

[slittlewing]

I used a 22Ah YUASA sealed lead acid on my jetbike to power 2x 044s and an oil pump. The jetkart used to have a 16Ah 5S Lipo, now it has a 16Ah 6s Lipo. Any decent 12v battery that can deliver 20A continuous should be suitable for driving an 044, be it a car battery or whatever.

There is no better solution than a Bosch 044 for a simple to use and widely available fuel pump that can deliver 150psi.
I don’t think it’ll do 200psi as there maybe be an internal relief but in any case that pressure is not required for most oil burner nozzles or for adequate atomisation.


For oil pumps I used A Marco UP9 on my jetbike, it has plenty of grunt and flow and I PWM controlled it, thy also sell a larger UP12 but I would think it unnecessary for most setups. The kart has a hydraulic pump (vivoil 3.2ccm/rev) combined with a brushless 63mm motor and vesc of which both I recently upgraded.

The Marco oil pumps are a solid choice for simplicity on the oil side. Bronze gears and a hefty dc motor.

Cheers

Scott

[cebaero]

Aug 15, 2024 13:03:13 GMT -5 slittlewing said:

I used a 22Ah YUASA sealed lead acid on my jetbike to power 2x 044s and an oil pump. The jetkart used to have a 16Ah 5S Lipo, now it has a 16Ah 6s Lipo. Any decent 12v battery that can deliver 20A continuous should be suitable for driving an 044, be it a car battery or whatever.

There is no better solution than a Bosch 044 for a simple to use and widely available fuel pump that can deliver 150psi.
I don’t think it’ll do 200psi as there maybe be an internal relief but in any case that pressure is not required for most oil burner nozzles or for adequate atomisation.


For oil pumps I used A Marco UP9 on my jetbike, it has plenty of grunt and flow and I PWM controlled it, thy also sell a larger UP12 but I would think it unnecessary for most setups. The kart has a hydraulic pump (vivoil 3.2ccm/rev) combined with a brushless 63mm motor and vesc of which both I recently upgraded.

The Marco oil pumps are a solid choice for simplicity on the oil side. Bronze gears and a hefty dc motor.

Cheers

Scott

This was very helpful, thank you!

So my 9ah battery is probably the issue? Also, you say it powered 2 o44 pumps, did you add these in series to increase the pressure on one line, or were they for separate systems? Even if you didnt, would I be able to add 2 in the same series as to increase pressure to 200psi?

I know you say that 200psi is usually not needed but for my specific nozzle and turbo i need about 200 psi for my ideal nozzle flow rate

[slittlewing]

Post a picture or link to the pump you have purchased please. I would suspect the pump is not the correct type.

I would change nozzle to a larger size to accommodate 150psi feed once you have the engine running on liquid fuel. There isn’t really a need for 200psi.
I experimented with a range of stainless nozzles on my jetbike which varied between 11.5 and 17.5gph on my jetbike (67mm inducer) for example.
Cheers

Scott

[cebaero]

Aug 15, 2024 14:04:46 GMT -5 slittlewing said:

Post a picture or link to the pump you have purchased please. I would suspect the pump is not the correct type.

I would change nozzle to a larger size to accommodate 150psi feed once you have the engine running on liquid fuel. There isn’t really a need for 200psi.
I experimented with a range of stainless nozzles on my jetbike which varied between 11.5 and 17.5gph on my jetbike (67mm inducer) for example.
Cheers

Scott

www.amazon.com/JDMSPEED-Pressure-Universal-Replacement-0580464070/dp/B07KQ184SG/ref=asc_df_B07KQ184SG/?tag=hyprod-20&linkCode=df0&hvadid=692875362841&hvpos=&hvnetw=g&hvrand=6685862109036501345&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9015297&hvtargid=pla-2281435178298&mcid=2d0ad0c3587e3a5ea09ffd61cbf85d4e&hvocijid=6685862109036501345-B07KQ184SG-&hvexpln=73&gad_source=1&th=1

If this is the wrong, is there anyway you could send me a link to a correct one? They all blend in and have the same specs as far as I see.

Also, I tried to find a nozzle that would accommodate my required flow at a lower PSI, but I could not find one that would fit in my current set up besides my current nozzle. As long as I can get to 150 psi my engine should run, I just wanted room for throttle.

[racket]

Hi

Just use the pump you have with a larger battery and get the engine running , your actual fuel requirements might be different to the "theoretical" depending on a number of variables , once it running you can then determine whats required , its always safer to be a bit under fueled for those initial firings .

Cheers
John

[slittlewing]

The pump you have purchased is a normal one for 3 to 5 bar. It says max pressure 8.5bar in the description.

A 10bar pump is shown below.

Cheers

Scott

www.ebay.co.uk/itm/175584155148?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=tOCniKdHRWG&sssrc=4429486&ssuid=2RSzGBVyTz6&var=&widget_ver=artemis&media=COPY

[cebaero]

Aug 16, 2024 2:21:33 GMT -5 slittlewing said:

The pump you have purchased is a normal one for 3 to 5 bar. It says max pressure 8.5bar in the description.

A 10bar pump is shown below.

Cheers

Scott

www.ebay.co.uk/itm/175584155148?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=tOCniKdHRWG&sssrc=4429486&ssuid=2RSzGBVyTz6&var=&widget_ver=artemis&media=COPY

Strange, seems like they dont sell the higher pressure ones in the USA? Looks like they only sell in the UK or Canada for some reason , maybe thats why I couldnt find one. Guess I'll just have to order one of those. Thanks!

[cebaero]

Aug 15, 2024 19:24:51 GMT -5 racket said:

Hi

Just use the pump you have with a larger battery and get the engine running , your actual fuel requirements might be different to the "theoretical" depending on a number of variables , once it running you can then determine whats required , its always safer to be a bit under fueled for those initial firings .

Cheers
John

Understood, I'll just try and get it up and running with what I got. In the future, if I wanted more PSI, could I put two 044 pumps into a series for more pressure? I was thinking if I just had the first pump on full power and throttled the second with a PWM this would prevent backflow. Do you think this would work to get me around 200psi?

[CMDR_Boom]

An idea for OP for future Big builds, power steering pumps of certain vintages that work more like a pressure washer pump (with some mods, pressure washer pumps themselves can be had relatively cheaply as replacement units but you'll need a lot of fittings) and can be underdriven with relevant electric motors, or if you're lucky, just get an el cheap electric pressure washer and motor controllers to undervolt it. If you want to put in better seals for liquid fuel, it's doable, too, but you won't find much reference material. Viton O-rings work great if you get into the guts. Rather than trying to work up to 200 psi, you need to work Down from about 1750psi. 😁 Makes one hell of a spray pattern with a good hollow cone conical nozzle. 
I'd have to go digging on old hard drives, but I've got some pictures and grainy cellphone footage of a full pressure spray pattern that's about 6 feet in diameter with a test nozzle, and a retrofit from a J something or other high-low circuit fuel nozzle. (J60 I think, it's been A While). I'd still go hardened hollow cone nozzle with a 5-15 degree pattern if it fits for your combustor size. I tried a 25* and a 60*, the 60 pretty much plastered the outer wall of my combustor and was mostly useless, even with 150psi incoming feed air.