If you’re an avid track day enthusiast, chances are you’ve starved your engine’s oil pickup at one point or another. Flicking the car left or right, accelerating, and decelerating can cause the oil in the oil pan to shift fore and aft, and side to side, uncovering the oil pickup, and ultimately causing low oil pressure surges.
An oil accumulator is essentially an aluminum, cylinder-shaped storage reservoir of pressurized oil that is released when there is a significant drop in oil pressure. The accumulator is connected to the pressure side of the engine’s oiling system and actually works off of the engine’s oil pump. Within the accumulator is a hydraulic piston that separates the air charge from the oil that is collected to pressurize the system. The oil side of the accumulator has an outlet that goes into the engine’s oiling system that is controlled by a valve. On the air side is a pressure gauge and sometimes a schrader valve for you to add your own pre-charge of air. Moroso and Canton offer oil accumulators of different sizes at great prices.
Installing an oil accumulator on your ride is one of the best investments that still fall on the “cheaper” side of car modification; it can even manually pre-lube engines before start-up to prevent cold-start scuffing and premature bearing wear. Our Evo X, for example, is tracked often and will benefit greatly from from an oil accumulator, which is why we’re installing one of Moroso’s oil accumulators. To learn more about the oil accumulators and their designs, we sat down with Moroso and Canton to pick their brains a bit.
Moroso’s oil accumulators can be purchased in a 3- or a 1.5-quart size, but for our application, we opted for the heavy-duty 1.5-quart unit (JEGS P/N 710-23903). As Moroso sells accumulators of different sizes, they offer the electronic pressure control accumulator solenoid valves for higher or lower discharge and refill pressures. Moroso sent us the 35-40 psi discharge/refill pressure control solenoid valve kit. Other pressures include 15-24 psi and 55-60 psi to fit the needs of engines used for different vehicles that generate different levels of oil pressure. The last piece to the puzzle from Moroso was the 20mm accumulator adapter spacer, which gets sandwiched by the oil filter. We like the fact that Moroso doesn’t sell these in kit form because it gives the consumer the chance to spec their own accumulator setup.
“It’s pretty common for a road raced car that endures a lot of hard cornering and hard braking to lose oil pressure or to see decreases of oil pressure at the pick up, so this acts as a fail-safe for when oil runs away from the pick up,” explained Jim Bianca of Moroso. “It pressurizes a reserve amount of oil to release into the oiling system to keep it primed.”
As long as the system is pressurized, it can be mounted virtually anywhere – Jim Bianca
“Traditionally, you wouldn’t want to install the Accusump under your hood where it is exposed to radiant heat,” explained Bob Vaughn of Canton. “A lot of people put them in the trunk, behind the back seat horizontally, but some people, depending on the car, are able to sneak them up in the grille in front of the radiator. Some sanctioning bodies even allow them in the car, usually located on the passenger side.”
Before we got our Evo X up on our trusty Bendpak two-post lift, we removed the bumper for easy access to the front end of the car, and also to scout out the perfect location for Moroso’s oil accumulator. With a little bit of scanning the different areas of the front end, we concluded that we were going to put the accumulator in the area behind the driver’s side fog light housing. However, in order to install the accumulator, a bracket needed to be made. “As long as the system is pressurized, it can be mounted virtually anywhere,” said Bianca.
Plumbing in the system can be done in several ways. If you’re already set up with an external oil cooler or remote filter, it’s just a matter of putting a T-fitting into the external AN lines, but in our case an oil filter adapter was the easiest way to connect it all up. Once we fitted the oil filter adapter to the oil filter mount, we installed the -10AN fitting to the adapter and screwed the oil filter back on. To determine how long of a line we needed to connect the accumulator to the oil filter adapter, we clamped down the accumulator to our freshly-fabricated mount and installed a male -10AN fitting to the accumulator.
“One of the most common ways to feed the oil accumulator into your motor is what’s called a sandwich adapter and that just screws in between your the oil filter and the block, which provides a single port right into the engine,” explained Vaughn. “You could also have an oil cooler or remote oil filter, and usually you would integrate the accumulator into the return line that goes back to the engine. There’s many different ways of plumbing it into the engine.”
With the oil filter adapter clocked the way we needed it, we installed the braided-steel AN line we made and marked the other side with a permanent marker where we needed to cut. Keep in mind that the line that connects the accumulator to the oil system will be different lengths, depending on the application and where it is mounted. After the desired length of the line was figured out, we took it over to the vice, clamped it in place, and began to cut at the spot we marked. Once the cut was made, it was less than five minutes until the line was completely finished and ready for installation.
As we already had the accumulator secured in the mounts, we took the finished braided-steel line and installed it between onto the adapter and accumulator with a perfect fit. However, the spot where we mounted the accumulator did cause a problem with the pressure gauge, so we popped it off and installed some push-lock fittings in place of the gauge, giving us the ability to mount it in a clever spot under the hood. After some thinking and poking around under the hood of our Evo X, we finally found a good spot to mount the gauge.
Ultimately, we chose to mount the gauge right next to the driver’s side headlight beneath the radiator support because it is out of the way of any fast-moving components. The spot we chose to mount the gauge also doesn’t need really long air lines; it’s in pretty close proximity to the accumulator.
Another problem area we ran into with our mounting spot was the manual air fill nipple to prime the accumulator, which is actually a crucial part of the accumulator because it needs to be pressurized to 60 psi before starting the engine to prime the system correctly. The accumulator needs to be primed after every oil change due to the pressure loss in the system once the oil filter is removed. What we did to remedy this was move the air fill nipple to the car’s frame inside the engine bay. For a clean look, we had to drill a hole in the frame rail. With the air fill nipple in place, all that was left to do was wire the system.
Before we wired the pressure control valve, we had to figure out a place to wire the switch. Luckily, there was a blank button next to the traction control button, so we decided to use that spot for our switch. Wiring up the electronic pressure control valve and pressure sensor was actually one of the easier parts of the install. We started by taking some of the red wire that came with the pressure control valve kit and crimped a butt connector onto the side that connects to the pressure sensor and then ran the wire to the positive terminal in the engine bay.
“When the pressure valve is electronically opened, the reservoir empties fast, but fills really slow. When it’s electronically off, the reservoir fills fast and holds the pressure,” Vaughn explained. “This is because there is a piston and two orifices in there, and when it’s open, it puts the valve in the right position to empty, but in the right position to empty is the wrong position to fill. So when we close up that second orifice and the other one is still open, it allows the piston to lift up and fill back up. That’s why we control them with the pressure switch; it gives us the best of both worlds.”
Once we were happy with the length, we cut the wire and crimped on an eyelet to attach it to the positive battery terminal with an in-line fuse that will connect to the switch in the car. Next, we cut another little piece of wire to jump from the pressure switch to the pressure control valve for power. After that, we got some black wire of the same gauge, crimped an eyelet and butt connector on there, and connected our pressure control valve to a nearby ground. We ran the wire from the in-line fuse to the switch in the car and we were good to go.
In an afternoon, we installed, plumbed, and wired Moroso’s oil accumulator, giving our engine automatic protection against dry starts and oil starvation should the pump pickup get uncovered. We can expect extended engine life both due to the pre-oiling function helping to eliminate normal wear and tear, and avoiding catastrophic damage in the event of a problem with the normal oil supply. Either way, Moroso’s oil accumulator is a cost-effective way to protect your investment in any engine, at the track or on the street, and the addition of the electric valve system makes it a no-brainer – turn on the ignition, and you’re protected.