Davidc1, I prefer the analogy of a a Macallan 18 scotch swirled in a glass rather than a turd flushed in a toilet, but I agree ;-)


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On that trace the lateral G scale is -1.5 to 1.5. Graph is of just T1 at the spin, so about 10s. Ramp down to min pressure was about 3s. Still learning the software so graph is imperfect and I'm not able to get to the laptop until this weekend.

Accusump would have likely worked fine. My lack of talent plus an installed data aq system will result in future Canton-influenced spin traces I'm sure ;-)


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SHG_Mike, the only problem I have with your sound logic is that this trace profile and lo-low pressures only occur during the two spins. The ramp down in pressure also starts with fairly high revs. I'll post better graph with more data points this weekend.

Question for all: what data points would you like to see? I can do several graphs to avoid "death by squiggly line clutter" (technical term from my Berkeley engineering days ).


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I posed your question to Canton. While the baffled oil pan does hold more oil right around the pickup, it would simply be a matter of when the oil was all sucked up by the pickup. The spin would still keep oil from flowing down around towards the pickup. The oil would be kept out towards the edge of the pan by the 0.8g's of centrifugal force. The Accusump would definitely work better for this type of thing, because you would have 10 to 15 seconds where the Accusump would be injecting oil into the engine under pressure to keep the oil pressure up. Hopefully your spin would not last that long!

 

Lack of talent has made me good at "when in a spin, two in" 8-0


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I didn't mean to say that the pressure drop didn't have anything to do with the spin, but rather it would not be caused by the G's of a spin as a high speed sweeper would cause more G load slosh for a longer period of time than any spin in the real world could induce.

I would try to look through each data trace and try to find an irregularity that also coincides with the time of the spin.

What is your normal hot after a session oil pressure at idle?

You may have a combination of Idle engine speed(low pump speed) + some level G force which almost never happens under normal operation or normal high speed/G cornering.

Either way an accusump or oil accumulator is a simply easy fix to whatever may be causing this.

 

But....

Even though 0.8G's is not as much as a sweeper at a little over 1G, you have to consider the distribution of the volume of oil in the pan. In a sweeper, all the oil in the pan would be pushed towards one side. Perhaps, depending on the shape of the pan, and the amount of oil in their (we don't know really how it all plays out down there), the pickup is still covered by a significant amount of oil, such that it would become uncovered only in a very long very high G sweeper. Yet, in a spin of 0.8G's, the oil would be pushed towards all four sides, perhaps enough to uncover the pickup very quickly as the oil is pumped out.

 

Again, it is my belief and opinion that there is no way the car can spin fast enough to push the oil up on all four sides. This is where our theories differ.

The car would have to spin 4-6 times in a matter of seconds. Also to achieve this swirl effect the center axis would need to be the center of the pan. If the car spins on its center axis ~ the drivers position, the centripetal force would move the oil to the front of the pan, in the same manner heavy braking would.

The OP did not describe the length or duration however in most cases it is very unlikely the car even went once around.

 

I really don't see why a 0.8g spin would be much different on the oil system than normal track driving where we hit over 1g braking and around 1g in turns. I think the big difference here is probably engine rpm. If you stomp on the brakes before you get the clutch in the engine will slow with the tire rotation.

The oil won't be pushed toward all 4 sides in a spin. When the spin starts the oil (and driver) feels lateral g. As the car rotates the g shifts to the rear and the oil would shift to the rear of the pan. As the car continues to rotate the g will rotate too due to the deceleration caused by the skidding tires.