dry sump

[bob]

so    dry sump oil system, electric or engine driven scavenge pump,? the electric scavenge pump sucks the same regardless of r p m.   the engine driven scavenge pump changes with r p m.  am using the stock engine oil pump. stock oil filter position  . using a dry sump pan. remote oil tank and  in line cooler.  also, any thoughts on  the in line oil cooler position, between scavenge pump and tank, pressure side ?  or out of tank on the inlet to engine oil pump. my thought is between scavenge pump and tank, to cool the oil before the tank.    small displacement, 2 cylinder. not a ton of horsepower would the engine driven scavenge pump rob any kind of power away . were the electric pump uses no engine power..      thanks       bob

[Rex Schimmer]

Bob,
I like your thinking about an electric driven scavenging pump, just make sure that it is several times the size of the engine oil pump. As rpms increase the engine pump put out more oil up to what ever the system relief valve is set so your scavenger needs to be larger than that. If you are only going to run one filter I would put it between the scavenger pump and the reservoir, make it big and make it at least 10 micron. I would also consider one between the engine pressure pump and the oil inlet to the engine just to catch any thing that may get into the oil when you fill the oil tank. New oil is not clean. Oil pumps don't draw much power, the calculation is: HP= GPM x PSI/ 1714 x (pump efficiency) So a 10 gpm pump at 100 psi and 50% efficient (gear pumps are typically pretty in-efficient) would be about 1.2 hp. I would also think about a circuit that monitored the electric pump if it was not running the circuit would stop the engine.
Rex

[jimmy six]

I tried one my GMC and it didn't pull enough vacuum. It was a GM Camaro/Impala V8 to assist the brakes with early injection systems. At the time I couldn't run a belt. The GMC has a lot of internal volume. I currently use an Aero Space Systems and pull 9" at top speed about 2/3 crank speed. A Moroso will probably do the same. They have 3 or 4 vane pumps. Good luck...

[Jack Gifford]

Before reinventing the system (electric scavenge, etc.) I think you should first fully understand the traditional approach (time-proven, if nothing else). Having both pressure and scavenge pump flows as a function of engine speed is important. The scavenge flow is sized to exceed the pressure flow, but not by a great amount. This [necessary] over-sizing of the scavenge results in some amount of non-liquid oil (air and oil mist) being pumped to the tank. A tank designed specifically to do a good de-aerating job can handle the typical amount of "froth". But this depends on pressure flow and scavenge flow both being tied to engine RPM. An electric scavenge with sufficient flow to handle peak RPM would be pumping mostly air at lower engine speeds- a bad situation for maintaining 100% liquid oil to the pressure pump inlet.

[bob]

these were exactly the concerns I was thinking about with an electric pump, not being in sync with engine speed. either to much or to little suck at the wrong time. just a thought, to simplify plumbing. I suppose the idea sucks also. thanks for the info        bob