We’ve been in the process of building an Evo X into a race car for some time now and while running through all the engine modifications that we wanted to do, we came to the conclusion it would need a dry sump to handle the levels of acceleration the car would generate on the track. We started looking around on the web and didn’t see anything available that was meeting what we had in mind for bolt-on simplicity, engineered design and performance.
During the PRI show in December 2015, we talked with Dailey Engineering from Temecula, CA to see if they had a dry sump for the Evo X, and even though they didn’t, we inquired whether they would be interested in designing and developing one with our help. After looking at the products in their booth it was clear they had the expertise. We talked with Bill Dailey the owner who has many years of motorsport experience and he said they were interested in working together and we should talk further when we were ready. Since the car was mostly disassembled by March of 2016, we gave him a follow up call to see what all this project would involve. He discussed their capabilities and timing and we told him the car’s components were there for what ever was needed. We bounced some ideas back and forth; his covering the important design elements to incorporate and mine for bolt-on simplicity and being able to retain the A/C for those customers in hot climates that have serious track cars, but may still see some street duty.
After kicking things off in earnest we got to work with Billy the design engineer at Dailey leading the project and Eric, partner in VRPerformance and our engineer on this project, started getting all the packaging measurements between the body and engine. Eric sent him the critical components from the engine for him to build his model from. It was clear the biggest challenge would be fitting an additional pulley to drive the pump between the damper and frame rail. We knew using the OE damper wouldn’t work, so Billy acquired the damper drawings for the ATI and Fluidampr for the X and we ordered each to make sure everything would fit during mock-up once completed.
One of Dailey’s design elements is to integrate the pump and pan as shown in the X system below. The pan is machined from 6061-T6 and the pump from 7075-T6511 billet aluminum. Starting with the pan, the perimeter matches up with the ladder frame (aka girdle) on the Mitsubishi 4B11T engine. It bolts on using hardware that will be supplied in the kit from us at VRPerformance. You’ll notice the raised area that runs around the perimeter of the pan. It serves as a trough for the oil to collect in to be pumped out via the two scavenge sections of the pump. The pan also has screens integrated into the drain openings to keep larger debris out of the scavenge sections. If there was ever an engine failure, the cover can be removed for cleaning out.
The scavenge sections are the two with the black tubes joining them to the pan as shown below. The pump is from their SP (small pump) line utilizing a spur gear design that Dailey has found to provide a consistent oil pressure curve while minimizing cavitation.
Cavitation is term used to describe air mixing with the oil. We’ll breakdown the technical details of pump curves and a number of other topics in part 2. A ‘pump curve’ is the graphical representation of oil pressure versus engine RPM. It is very important to have the right amount of oil pressure for a given engine’s performance including; power, torque, operating RPM, bearing clearances, oil viscosity and operating temperature.
The scavenge sections of the pump use a roots type rotor or impeller that you would associate with a Roots supercharger. These pump oil and air from the pan to the oil tank. Dry sump systems hold the excess oil in a remote tank typically located in the trunk or engine bay. By removing the oil from the pan you eliminate the parasitic losses from the rotating assembly, e.g., crank and rods moving through collected oil that you would associate with a wet sump system. When parasitic losses are removed that increases power output and one of the main reasons dry sump systems were invented.
Another reason dry sumps were invented is the ability to supply pressurized oil at high levels of acceleration whether that be longitudinal or lateral. With race cars being able to brake and turn at high sustained g levels, the oil in a conventional wet sump will move up the wall of the oil pan leaving the oil pickup no longer submerged and unable to suck up oil to lubricate the engine. This has led to many engine failures. As a stop gap measure, many baffled oil pans have been created as means to reduce the pickup being starved of oil and certainly buy’s one some additional protection for short events of high acceleration. One additional benefit of the dry sump is, by eliminating the oil pickup, the depth of the oil pan can be significantly reduced allowing the engine to be lowered in the chassis. In our case, the engineering challenge to drop the engine, powertrain and half-shafts down is more than we have time to tackle. This is why locating the pump under the pan provided the best packaging and a few other things we’ll cover in part 2. Below you can see the system installed on the engine and mocked up in the car.
The pressure stage of the pump has it’s outlet run through a square tube turning up into the ladder frame supplying oil exactly as the OE pickup does. This adds to the bolt-on simplicity of the system. It has a robust high pressure capable o-ring joint where it meets the pan. The OE filter housing located on the Ladder Frame is retained and functions as before. Dailey Engineering has created a number of oil pump configurations beyond the standard one shown here that we’re using. The pump is expandable by an additional scavenge sections that can be used for crank case vacuum or scavenging from other parts of the engine, e.g., turbo. Dailey also designed an optional ‘regular pressure housing’ pump that will replace the square tube with an AN outlet from the pump allowing more of a custom plumbing setup for remote filter housing, cooler, etc. More details to follow in part 2 coming soon.
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