Dry Sump System
Out in the "operating room" (aka: the Banks ACE shop) they were earlier fitting what looked to be the oil pan. Only this "oil pan" isn't any old piece of stamped sheet steel. It's carved (OK ... actually CNC-milled) from a solid block of 6061-T6 aluminum and it's more correctly referred to as the engine's oil sump. It's one of the basic components of a racing dry sump system and it isn't really "dry" at all.
In truth, everything inside the block of this 1,200+ horsepower Duramax diesel engine gets "wet," that is it sees its share of oil ... But just the right amount at just the right place is the name of the game. Too little oil and the engine gets very unhappy, it might spin a bearing, score a crank, or even try to pitch a rod out the side of the block. Too much oil and the crankshaft and rods start using up valuable horsepower just to fight the pumping losses associated with having to splash though a thick batter of foamy oil in the lower crankcase. Somewhere between the two lies the perfect point of balance.
Moving all that oil around is a very obvious, multi-stage, belt-driven oil pump made by the Barnes Company. Modular in design, the engine builder can stack a series of individual pump units together to tailor the volume and pressure of oil to the needs of a particular system.
The Sidewinder's Barnes pump is a seven-stage device that has five scavenge and two pump units in its almost 20-inch length. Aptly-named, the scavenge pumps suck the oil out of the engine for a quick trip through the "dry sump" tank where the oil is de-frothed, cooled off a bit, and then headed on its way right back to the engine by way of the high speed side of the oil pump. The normal working oil pressure for this engine in the 70 to 90 pounds-per-square-inch range, and the oil is a full synthetic 50-weight oil from Redline.
The billet pan on the Banks race machine is only about two and half inches deep with a multiple compartment interior and large drains that lead to a massive CNC-milled (again right at Banks) out of a piece of solid aluminum.
With the possible exception of gratuitous graphics, on most racecars nothing ever just goes along for the ride, and many items serve more than one purpose. This oil pan serves at least three causes. Obviously there's control of the engine oil, and nothing else matters if that ain't there.
Second, when Banks spins a 6.6L Duramax diesel up to (and over!) 5,000 revolutions per minute, the crankcase (even a four-bolt main one like this one) can use all the help that it can get and this thick, rigid design is made to do just that, keep the crankcase nice and straight in spite of all the giant mechanical forces acting on it.
Thirdly there's ground clearance. In the Chevy or GMC pickup truck that this engine was originally designed for, it was designed to sit high in the chassis, so the (properly named) "wet sump" (or as we call it "the oil pan") has plenty of room below the engine block to catch all the oil before returning it to the oil pump. In racing cars, (and this long, low Banks Sidewinder is no exception) getting down close to the ground is an asset, and that's were having virtually no oil pan is not just an asset, it's a necessity. This one ends right at the frame rails with no protruding drain plug and all the outlets on the side as opposed to the bottom.
Small stuff (in the big picture of a complete race car an oil pan might be thought of as "small stuff") and sweating out every tiny detail of a project race car is the real process here. This is where a company like Banks gets what they call "proprietary" information, original data, simply unobtainable any other way, that lets them build cutting edge products.
There really are no deep, dark, written-in-stone, secrets at Banks.
However, if superior preparation, engineering, design, fabrication, testing, (more testing), and obsessively precise fitting of parts mean anything, you can mark them down as traits (good habits, normal practice, standard operating procedure) that are the not-very-well-kept "secret" of Banks' success.
