One of the biggest weapons in oil-control technology is the trap-door baffle within an oil pan. Unlike static baffles, like those that would be found in a Flowmaster muffler, trap-door baffles open and close to allow almost unrestricted one-way fluid flow, while effectively limiting flow in the opposite direction. Moroso has released a video which details their extensive use of trap-door baffles across their line of oil pans.

“The trap-door baffle assemblies are arranged in a manner which allows oil to go from non-pickup areas to the sump pickup area. The doors have wired hinges, which only allow them to open about one-third of the way,” says Scott Hall of Moroso Performance.

“If the door were allowed to open any more that that, it would take too long to close, and allow so much oil to pass by, that it wouldn’t really be doing anything at all.” While the door only opening about 60-degrees may not seem like a lot, when you consider the size of the passage, it becomes apparent that there’s really no restriction to flow.

The simplest of all of Moroso’s baffle designs, the street/strip and drag-racing oil pan only needs to control oil in two directions - forward and backward.

When it comes to oil pan applications, drag racing and street/strip style pans are by far Moroso’s most popular designs. However, it is also one of the simplest designs in regards to trap-door baffle configuration, as it only needs to control oil under acceleration and deceleration.

“All of the designs from street/strip to Top Fuel oil pans incorporate a horizontal baffle,” Hall says. “The trap door allows the oil to move towards the pickup under acceleration, and prevents oil from escaping the pickup area and starving the enging under hard deceleration.”

When engineering their road race pans, there are additional forces that need to be considered, namely lateral ones.

“The road race baffling system not only has acceleration and deceleration to deal with, but also left and right turns,” says Hall. “The duration of these movements can be continuous, which can cause oil starvation. To counter that, Moroso developed the diamond baffle.”


Moroso’s diamond baffle consists of a square arrangement of trap door baffles, rotated 45-degrees. Each side has its own trap door opening inward (towards the pickup) in order to keep the pickup fed under all kinds of combinations of forces.

“The diamond baffle can be installed in any pan that Moroso makes and can even be used with the OEM oil pickup in some cases,” Hall says.

For those with unique applications that may not be in the catalog, no longer do you need to go through the time and expense of having a custom pan fabricated, as Moroso has drop-in solutions to improve OEM oil pans. “These assemblies go right into the OEM pan. Once it’s installed onto the factory mounting points, it gives much better oil control to the stock pickup than the OEM baffling, if there is even any to begin with,” says Hall. “Most will work with your OEM pickup tube, making it one of the cleanest solutions for an OEM engine that just needs some additional oil control.”

Moroso’s “diamond baffle” features four trap-door baffles to keep the sump fed with oil under any combination of acceleration, deceleration, and cornering forces.

Finally, Moroso’s most complex system of baffles goes into their circle-track pans.

“Circle track pans are quite complex, due to the number of trap door assemblies that need to go into the pan to make it function properly,” says Hall. “The small-block Chevy oval-track pan has five separate trap door assemblies in various locations and angles, in order to manage acceleration and deceleration as well as the continuous lateral G-loads.”

The complex arrangement of trap-door baffles in the circle-track oil pan is such that it almost creates three individual sumps in the shallow, wide oil pan. When you consider the extreme forces – in both overall intensity and duration – in a circle-track application, the trap-door baffle really proves its effectiveness.

The circle-track baffle system is the most complex, consisting of five separate trap-door baffles in order to accomplish the huge task asked of it.