[The Radium King]

from what i've read, the issue is not with the supply pump, but it's ability to scavenge adequate oil in high-g situations (either the oil gets stuck in the heads, or the oil sloshes away from the pickup). so, no need to replace the pump, just improve scavenging by tying it direct to the reservoir.

i think the issue with my soln is to get adequate scavenging in a low-budget dry sump system. at max honk the supply pump moves what, 12 gpm? from the little bit of reading i've done, you want scavenging at 2x the supply amount, which means a 24 gpm max pump. with a belt-driven system the scavenging is rpm-sensitive as much as the supply so you are not moving 24 gpm all the time. also, most belt-driven pumps have two (or more) scavenge stages for each supply stage. with electric you are stuck with one rpm, not to mention that 24 gpm is a lot. on the link i posted previously, a 4 gpm electric pump was $500. perhaps two or three smaller pumps - one on always and the others on an rpm trigger? at that point, however, the cost and complexity make it just as easy to put in a belt driven pump. so, back to a standard dry-sump system.

another thing. reading the rennlist posts, the thinking seems to be that the scavenge issue is not so much with the supply pump not being able to find oil in the sump, but rather that the scavenge pumps in the heads (the two #10's in the diagram) can't find the oil (pushed away in high-g situation) so oil builds up in the heads and doesn't make it to the sump. what i am wondering is: what is the role of the overpressure valve in the supply pump? could the failure of the scavenge pumps in the heads create a false pressure situation such that the overpressure valve is opening and recircing oil directly back to the sump and not moving it through the engine? perhaps a stronger spring here to force the pump to push the oil through and into the scavenge pumps in the heads? EDIT - note that porsche did upgrade the piston in the overpressure valve to a 997 part # ...