Super long oil lines - Pressure drop possibly an issue?

[dnegative]

Either way that sounds like a bit of pressure loss. But being a positive displacement pump, the flow rate of oil through the lines should always be the same no? And thus that means that the pressure on the bearings themselves shouldnt change, so this "pressure loss" calculated above is more a measure of the extra strain the pump has to overcome, does that make sense? My brain is hurting lol

What does old mate Pascal reckon, pressure exerted on a fluid is equal and undiminished in all directions, no pressure differential......?

I guess the added friction from the line would restrict flow..... increase pressure?

idk

[trdee]

But you cant restrict flow through a positive displacement pump. Thats why the trusty 4AGZE has the throttle body pre superharger. If it was post supercharger (and with no bypass valves) then the supercharger would seize. The only flow loss you should get in a PD pump is leakage around the sides of the pump...

You may be right on the hardline topic. If i do end up going with a front mounted cooler then i will give it some serious thought. For the moment I am just trying to figure out whether it's worth bothering with at all hahaha!!

Also i just realised the flow rate I am using is the total flow capacity of the pump, so a fair bit of that flow will actually be going back in through the bypass valve anyway. So the "pressure loss" ought to actually be less than that....

[dnegative]

How do you think you get pressure? Pumps create flow not pressure, a restriction to flow creates pressure.

And a variable swashplate piston pump is a way around a fixed pump

[trdee]

you can have the same flowrate but through a smaller gap to get that pressure

Think about it. the sc12 displaces 1.2L/rev. it doesnt matter if its through a pinhole (high pressure, high strain) or into a huge fucken box (no pressure, negligible strain), it will always displace 1.2L/rev. That be the operating principle of a positive displacement pump right there...

[dnegative]

Hence the pressure relief valve, very bad things happen when you deadhead or make something on the outlet too small on a positive displacement pump. Something has to give, although its not as bad for air as it compresses

[masterofsinanju]

So for this application trdee is not likely to lose pressure but possibly have flow issues? (although relatively minor?)

(Pascal eh, that thing still around. Here was I thinking Boyles law but then there can be no volume change with a liquid right?)

[dnegative]

Maybe, he is the engineer I'm sure he will wort it out

[trdee]

i cant have flow issues unless i cause a high enough restriction for the pump to seize. the only issue i can see in terms of pumping is that the oil pump will be under more strain, but not as much strain as it is under by shimming the pump up 20 odd psi like many people do, so shouldnt be an issue...

oh yeah and the lines/fittings are all -8

[4th surf]

Same thing but a little different and going back a few years. The engine in question here was a diesel Ford 2713E (360 cid 6 cyl) and was one of two fitted to a 50 foot motor yacht I was the engineer on. The issue here was being able to not only access the oil filter on the starboard engine but also the issue of oil spills during engine service changing said filter. Now due to needing to run W2O oil coolers as part of the engine cooling system hoses of some 1.8m length were already fitted. During refit one year I relocated the oil filters of both engines to the aft bulkhead. This meant longer oil lines of some 4m each. I kept to the same sized hose as original and given that both engines were marine diesels high volume oil pumps were standard. Priming the lines if and when needed was never an issue and no loss of oil pressure noted. Infact the increased length of the oil lines helped to cool the oil believe it or not.

What I'm saying is mounting the oil cooler down the front with longer lines won't be a problem if done correctly.

[trdee]

yeah i currently have something in the order of 4m of oil lines in the fucker already hahaha

thank you for sharing your experiences 4th surf. good to hear from someone else who has done something similar with their oil system (even if the application is very different lol)

[Billzilla]

W2O cooler should give you more consistent temps (and quicker warmup of oil). Doesn't have to be stupidly expensive but size and flow need some consideration.

You could mount the cooler in the boot out of harms way?

Bill's cooler was this

tho I think he changed it to a Subaru (?) W2O cooler. I think his build thread here or on PF has more info.


edit: found build thread on PF, yes it's not a 4A donk, but it's race proven.

Current cooler is from a Subaru, is a donut cooler mounted between filter and block. Engine runs a scavenge pump for the dry sump but feeds the collected oil direct to the factory oil pump.

What he said!
I'm totally sold on water/oil heat exchangers, better in just about every way.

[trdee]

as previously, brendan was using a celica water to oil cooler with no success. is the subaru unit capable of greater heat duties?

[SHEPPO3930]

the most important thing to note in Bill's set up is he's running the cold water (from the radiator) through the oil cooler FIRST, even before the water pump.

i'm taking a guess here, but... i'd say it's done this way to not only get the coolest water possible through the oil cooler, but also making the oil cooler almost redundent until the engine's coolant thermostat is open. when the coolant thermostat is closed, there's no flow through the radiator, thus no flow through the oil cooler, allowing the oil to warm up.

Bill correct me if i'm wrong.

sorry to go OT, but there's some great info in this thread about oil cooling, regardless of the original question.

[Billzilla]

the most important thing to note in Bill's set up is he's running the cold water (from the radiator) through the oil cooler FIRST, even before the water pump.

i'm taking a guess here, but... i'd say it's done this way to not only get the coolest water possible through the oil cooler, but also making the oil cooler almost redundent until the engine's coolant thermostat is open. when the coolant thermostat is closed, there's no flow through the radiator, thus no flow through the oil cooler, allowing the oil to warm up.

Bill correct me if i'm wrong.

sorry to go OT, but there's some great info in this thread about oil cooling, regardless of the original question.

No, the water to the cooler comes from the water pump but it's still from the cool side of the radiator. However, the cooler needs a bit of pressure differential to get the water to flow through it so it returns the water into the inlet pipe to the water pump. Perhaps not the best and I maybe should have put it into the water-in to the radiator but it all seems to work fine.
The oil temp runs about 30deg warmer than the water and the water runs very cool.

[SHEPPO3930]

Oh, my bad.

Going by the pic (top pic in post #41), it looked like the pipe going from the oil cooler (black thing) to the water pump was the supply to the water pump.

Sorry for OT