Technical informaton regarding petroleum transfer wanted...

[Yowzer]

In regards to fuel heating up, my surge tank does actually get pretty warm.

Not sure if it's from the engine return or what, but I just assumed it was normal.

Ideally ya do want a return at the top of the surge tank to main tank so it can pump any air out.

Otherwise you will end up with air trapped in the surge tank

[fuel]

you would want a return from the surge tank to your fuel tank regardless, to return any fuel when the surge tank gets filled back up from the fuel rail return and the overflow when the lift pump supplies more fuel than the engine is consuming from the main pump.

a possible idea to make things simpler is have the fuel rail return line tee in with the return from the surge tank to the fuel tank - when the surge tank is not full the surge tank will get filled up, and when the surge tank is full the fuel will get directed back into the fuel tank. I figure under light loads the surge tank is going to be full most of the time so most the fuel will end up being dumped back into the main tank where it can cool down quicker.

[mikuni]

In regards to fuel heating up, my surge tank does actually get pretty warm.

Not sure if it's from the engine return or what, but I just assumed it was normal.

Are you running rubber fuel lines or steel/copper?

[xsspeed]

I've heard about the fuel heating up but I've checked my return a few times and its never even warm. I'd say the cool air running past the lines under the car would provide a massive cooling affect. To me, the heating fuel thing sounds like an idea that someone has come up with in their head, but I could be wrong.

Going back to this, even if return from HP pump went back to the surge tank, surely the flow and return from the main tank would change out the volume of fluid in the surge tank quite regularly? Therefore 'hot' fuel would return to main tank anyway.

[My name is Russell]

could leave my lift pump running for an hour or two tonight to see what happens heat wise. wouldn't get the same heat gain of the fuel that does pass through the fuel rail/plenum from engine running however.

[Yowzer]

In regards to fuel heating up, my surge tank does actually get pretty warm.

Not sure if it's from the engine return or what, but I just assumed it was normal.

Are you running rubber fuel lines or steel/copper?

Copper to the engine, rubber return

[mikuni]

In regards to fuel heating up, my surge tank does actually get pretty warm.

Not sure if it's from the engine return or what, but I just assumed it was normal.

Are you running rubber fuel lines or steel/copper?

Copper to the engine, rubber return

Interesting, I was hoping you'd say that. I bet with a steel or copper return you'd see a lower temperature at the surge tank. Not worth doing unless the temp was causing some sort of issue.

While we're on this subject, I heard form a few different sources that running en external fuel pump in the cabin would overheat it because its no longer getting cool airflow as it would under the car. Its just a normal waka/vl bosch fuel pump. I was abit worried about this at first, so had it open and checked it abit. I now have it wrapped in several layers with a thick woolen blanket to keep it quiet and it still runs cool - if you check it on a long trip its actually cooler than inside the car.

[Yowzer]

Yeah thought the same thing.

I will be redoing the system in the future, as what's there at the mo was just a slapjob to get the car running. Rubber hose cabletied to factory fuel line is not really ideal..

Someone on here had a surge tank mounted under their car next to the fuel tank? I recall seeing a pic somewhere, can't remember if it was here or not. That's the setup I plan on going for.

[ryanfels]

Someone on here had a surge tank mounted under their car next to the fuel tank? I recall seeing a pic somewhere, can't remember if it was here or not. That's the setup I plan on going for.

That might be me. It was mint for the wagon

[isnowi]

could leave my lift pump running for an hour or two tonight to see what happens heat wise. wouldn't get the same heat gain of the fuel that does pass through the fuel rail/plenum from engine running however.

I suspect it's the HP pump that gets accused of causing the heat, as it pressurises the fuel.

[My name is Russell]

Ahhh good point

[Brock-Lee]

hmm not that sure about that, fluids are easy as piss to raise the pressure on as they arent compressible, Id say a pump would struggle to transfer enough energy just by raising 40 odd psi at 200 lph.

[xsspeed]

What pressure does EFI line run at?, edit dumb question just looked above, didn't read all of brocklee's post.

But yeah unless you a re raising the pressure significantly wouldnt think the heat gain would be great as mentioned (unless petrol behaves funnily), and the heat off the pump itself would be minimal.

Would think that and temp gain would most likely all be from the engine bay

[isnowi]

The info i read was more concerned with the heat generated by the pump itself, apparantly they spin at 10000 to 20000 rpm, using the fuel that they pump as both lubricant and cooling, though as stated above the thermal efficiency of a couple of litres petrol is probably more than capable of dissapating that heat. I think i will run the return from the rails back to the surge tank and see how things go.

[Testament]

the pump will heat up the fuel a small amount but it would but almost negligible compared to the heat from the fuel rail bolted to the engine running at 80 degrees plus convected/radiated heat from the exhaust, radiator etc. meaning less temperature difference to reject the heat.

Pretty simply just need to find out what the boiling people of the fuel is at 3 bar, and the density difference between 3 bar liquid fuel at 20 degrees and at 80 degrees.

I'll find it out later if someone else hasn't, but right now I'm going to get some lunch.