2 Nov 2014

What do you do when you’re told by people that a dry sump is a silly idea – not a bad idea, just an unnecessary and expensive addition? Of course, other than cost, these same people also agree that it’s a great idea, so their actual complaint isn’t with what it does, but how much it costs to achieve it. (The irony is that several of those who said so run dry sumps on their cars.) I’m told that there are better ways:

– “Add an extra quart of oil.”
– “You don’t need one on a street car.”
– “You don’t have space for the tank.”
– “Unless the engine’s sucking air, it’s not necessary.”
– “Get an Accusump, they work practically as good for one tenth the cost.”

My opinion:
Extra quart: yes that works, to a degree, it’s just that no one knows to what degree.
Street car: Define “street car.” Please explain then why new Corvettes have dry sumps.
Not enough space: Says someone who hasn’t built a Midlana…
It’s not sucking air now: True, until it does, then I have $$$$ damage which I have to pay for, no one else.
Accusump: This takes a bit longer to explain –
I had one and didn’t care for it. It’s a tank of oil that’s pressurized to the same pressure as the engine’s oil system, so an equilibrium is reached where as long as the engine’s oil pressure doesn’t change (up or down), oil flows neither to nor from the tank. The idea is that if the oil sloshes away from the oil pump inlet, oil pressure will drop and the now-higher pressure Accusump will push its contents into the engine, “stepping in for” the engine’s failed oil system.

I don’t have an issue with the above; it’s the details that bug me. As the engine slows, engine oil pressure drops, so the Accusump starts pushing unneeded oil into the sump, which gets whipped by the crank until the engine speeds up again. As it speeds up, oil pressure begins increasing, now the engine’s oil pump is assumed to have the extra capacity to not only fully lubricate the engine, but also recharge the Accusump tank at the same time. What rubbed me the wrong was the salesman assuring me that their system has a special valve that charges the tank slowly, but releases the oil quickly – a one-way valve.

No. It. Doesn’t.

Lastly if the pump starts picking up air bubbles, they’ll pass through the pump and get compressed along with the oil. Because the air/oil mixture is compressed to standard oil pressure, the oil gauge (and Accusump) will not see any problem, yet the engine is still being starved for oil.

So as a reward for reading this far, here’s a YouTube video of Midlana and friends driving through San Diego’s mountains after a rain. (I should add that the coolant coming from the Evo was simply an overflow tank that… overflowed, no actual problem.) It was a lot of fun, and reminds me to get Midlana back on-track!.