Direct injection offers numerous benefits. By injecting fuel right into the cylinder, the powertrain control module can exhibit more control over the fueling. The placement and control yields more performance and lower emissions, but as with any technology there can be downsides. Some are annoying, like a sooty exhaust tip, while others, like low-speed pre-ignition, might cost just you an engine.
Simply put, direct-injection engines create higher levels of fuel dilution in the motor oil, and that creates specific problems. — Lake Speed Jr., Driven Racing Oil
In the United Kingdom there is a racing series called the Mini Challenge, where the race engines run direct injection. After a rash of engine failures at races, the series organizers sought out a solution.
“Once the series organizers and engine builder became aware that failures were due to LSPI, the series fuel supplier, Sunoco recommended contacting Driven Racing Oil,” Lake Speed Jr., Lubrication Specialist at Driven Racing Oil, said. “That call resulted in a change to Driven’s XP9 Racing Oil that contained only 250 ppm of Calcium detergent compared to the previous oil with more than 2,500 ppm of Calcium. Just changing the Calcium level eliminated the LSPI related engine failures.”
It turns out that the lubrication gurus at Driven Racing Oil and already been working with the scientists at the Oak Ridge National Laboratory, who were given a grant to come up with a better oil formula for direct-injection engines.
“It is hypothesized that Calcium and Sodium detergents chemically react with the fuel to create a third chemical that is neither fuel nor motor oil. This third chemical has a lower octane value than either the fuel or the motor oil, so the detonation resistance is lower,” Lake said. “Because of the lower detonation resistance of this ‘blended’ molecule, abnormal combustion results, which we call Low Speed Pre-Ignition. This was proven-out by blending oil formulas that eliminated Sodium detergents and greatly reduced Calcium detergents. These research formulas also eliminated LSPI events.”
With that in mind, Driven developed its new line of DI-specific oils, which combine Driven’s methodology of using the best possible lubricants for the application with detergent additives that don’t amplify the chances of low-speed pre-ignition.
“Simply put, direct-injection engines create higher levels of fuel dilution in the motor oil, and that creates specific problems,” Lake explained. “Traditional motor oils contain high levels of calcium based detergents. These calcium detergents help with fuel economy, prevent rust and keep the engine clean. However, these same calcium detergents also increase the tendency of an abnormal combustion event, also known as Low-Speed Pre-Ignition. LSPI events can destroy an engine, so motor oils are being reformulated to reduce the tendency for LSPI to occur.”
The resulting DI oils — available in 0-W20, 5-W30, 0-W40, and 10-W60 — are designed to not only alleviate the risk of LSPI, but protect against wear from soot in the oil, lower crankcase vapors, and reduce carbon buildup on the valves. All these can be issues with direct-injection applications.
“Driven currently has a line of motor oils formulated specifically for direct-injection engines, so these motor oils provide the highest level of protection and performance for direct injection engines,” Lake said.
Of course, these oils are of particular interest to owners of Ford’s increasingly proliferating gas-turbo direct-injection-powered vehicles that run under the EcoBoost branding.
“Some EcoBoost engines use a side-mounted injector location, and that can increase the amount of fuel dilution, which increases LSPI tendency,” Lake said. “It is important to use properly formulated motor oils in EcoBoost engines to get the best performance and protection.”
If you own a 2018 Mustang with the latest, dual-fuel Coyote engine, you might be thinking you don’t need a DI-specific oil. Don’t be too hasty though. Though the addition of port injection does mitigate some of the DI-only issues, it doesn’t mask them all.
“The dual-injection system helps to overcome some of these issues. Essentially, the engine is programmed to operate as a port-injection engine under the conditions where LSPI is most likely to occur, and then the engine switches to direct injection once it is out of those conditions,” Lake said. “On paper, this sounds like a good mechanical solution to the LSPI problem, but it has not been proven to completely prevent LSPI from occurring while using traditional motor oil formulas.”
So, it wouldn’t hurt to run oil designed for direct-injection engine in your dual-fuel Gen 3 Coyote, but not just to keep detonation at bay. That soot you see on the exhaust tip can also create extra wear.
“It is also worth mentioning that all direct-injection engines, even dual-injection system engines, create soot, and DI soot can increase wear,” he added. “This is one of the formulation considerations for direct-injection engine — you have to design the oil to handle the soot.”
To verify the functionality of its DI oil line, Driven tested the DI30 oil in a Focus RS. First the company submitted used oil from a factory fill for analysis. Then used oil from a Driven DI fill was put through the same battery of tests.
“The used-oil analysis report revealed higher levels of wear with the factory fill oil than the Driven products,” Lake said. “This confirmed the fact that the mainstream motor oils were not designed specifically for direct-injection engines. When a lower-calcium-level oil was used, the engine performance and protection increased.”
So, especially if you are looking to push the performance envelope on your EcoBoost-powered Ford, you might want to take a look at the Driven DI oils when it’s time for your next oil change.
“The Driven DI line of direct-injection engine oils provide the correct chemistry for direct-injection engines, so all you have to do is choose the viscosity Driven DI that meets the viscosity requirement listed in your owners manual,” Lake added.