Synthetic Oil: Power and Performance Myths

Synthetic Oil: Separating Fact from Fiction

The world of automotive lubricants can be a confusing one, especially when it comes to synthetic oils. With many adventure and dual-sport motorcycles now requiring synthetic motor oil, a host of myths and misconceptions have begun to circulate. Given that synthetic oil is often a more significant investment than its conventional counterpart, it's crucial to make informed decisions about its use. The advancements in motor oil technology, particularly synthetics, have undeniably played a pivotal role in the incredible performance capabilities of modern vehicles. To help navigate this complex landscape, we've consulted with Joey Cabrera, Motul's National Technical Director and a seasoned rider himself, to debunk some of the most persistent myths.

Does Synthetic Oil Increase Horsepower?

This is a question that often sparks debate. While not a universal guarantee, some synthetic oils have been proven to increase horsepower in specific applications. This is often due to their superior ability to reduce friction within the engine. By minimising the internal resistance, more of the engine's power can be delivered to the wheels. For instance, certain racing-specific synthetic oils are formulated with additives and base stocks designed to maximise power output.

Myth 1: Regular Oil Changes Mean No Need for Synthetic Oil

Joey Cabrera clarifies that while regular oil changes are essential, synthetic oils offer benefits that conventional oils simply cannot match, even with frequent changes. Synthetics provide superior protection under extreme heat conditions and exhibit better flow characteristics in very cold temperatures. This translates to a cooler, smoother-running engine. Crucially, synthetics are engineered to withstand higher temperatures and resist breakdown under heavy loads, which is vital for high-performance engines. Furthermore, many synthetics incorporate Esters, which create a protective film on metal components, safeguarding against wear during cold starts.

Myth 2: Never Use Synthetic Oil to Break In an Engine

This is largely true. Conventional oil is generally recommended for the initial engine break-in period. The reason behind this is that conventional oils are less slippery, allowing the piston rings to seat effectively against the cylinder walls. High-quality synthetics, being more slippery, can potentially prolong this process. Most engine builders advocate for breaking in an engine with conventional oil for the first 300-600 miles before making the switch to synthetic. Motorcycle manufacturers often follow this practice, filling new bikes with conventional oil for the initial break-in, even if synthetic is recommended long-term.

Myth 3: Once You Switch to Synthetic, You Can't Go Back

This is a persistent myth. It is perfectly safe to switch back to conventional oil or to mix synthetic and conventional oils. Many products on the market are synthetic/conventional blends, specifically designed to offer a balance of performance and cost. These blends provide many of the advantages of synthetics, such as improved additives and better refinement, at a more accessible price point than full synthetics.

Myth 4: Synthetic Oil Isn't Derived from Petroleum

While synthetic oils are artificially created lubricants, their base material is still overwhelmingly crude oil. This crude oil undergoes a rigorous distillation and refinement process, involving chemical and physical modifications. The term "synthetic" refers to the advanced manufacturing process rather than the origin of the base material. Think of it like glass, which is made from sand but is not called "synthetic glass." The specific synthesis process and additive packages are proprietary to each manufacturer, leading to variations in performance characteristics.

Engine oils are categorised into five groups. Groups I and II are mineral (conventional) oils. Groups III, IV, and V are considered synthetics. Group III oils are highly refined mineral oils, often hydrocracked for greater purity. Group IV oils, typically polyalphaolefins (PAOs), undergo a specific "synthesising" process. Generally, Group IV oils outperform Group III in terms of heat resistance, oxidation stability, cold-start performance, and film strength. However, modern technology has seen some Group III oils achieve performance levels comparable to Group IV. Group V synthetics, often based on Esters, are derived from natural sources like vegetables, minerals, and animal fatty acids. Esters are more expensive due to the complexity of their synthesis but offer exceptional high-temperature performance and a strong electrochemical bond to metal surfaces, resulting in superior wear protection.

Myth 5: It's Okay to Use Conventional Oil if Your Manufacturer Recommends Synthetic

This is a critical point. If your motorcycle manufacturer specifies synthetic oil, it is strongly advised to adhere to that recommendation. Engineers design engines to operate within specific tolerances and characteristics, and the recommended oil is integral to that design. Using a lower-grade oil can compromise the engine's longevity and performance, especially in demanding conditions. For adventure and dual-sport riding, where engines are often pushed to their limits away from immediate assistance, the enhanced protection offered by synthetic oils is invaluable insurance against potential failures caused by extreme heat or mechanical stress.

Myth 6: No Difference Between Motorcycle and Car Engine Oils

This is a dangerous misconception. Car engine oils are formulated with different priorities, often including friction modifiers to enhance fuel economy and reduce emissions. They also contain detergent additives with higher ash content, which can lead to deposit formation in motorcycle engines, potentially causing component damage. Motorcycles, unlike cars, typically use the same oil for the engine, gearbox, and clutch. Therefore, motorcycle oils are uniquely formulated to provide adequate lubrication for all these components. They must be slippery enough for the engine and gearbox but not so slippery that they cause the wet clutch to slip. Car oils lack this specific balance and can lead to clutch slippage, power loss, and premature wear.

Always use oil specifically designed for motorcycles, adhering to the JASO (Japanese Automotive Standards Organization) rating system. JASO MA, MA1, and MA2 ratings indicate oils that are safe for wet clutches, with MA2 offering the best clutch performance. JASO MB is designed for scooters with automatic transmissions and should not be used in motorcycles with wet clutches.

Myth 7: Any Synthetic Oil with a JASO Rating is Suitable

A JASO rating is a vital indicator, but it's not the sole criterion. Some automotive-based synthetic oils may carry a JASO rating but are not specifically formulated for the unique demands of motorcycle engines. It's essential to use oils designed for motorcycles, considering their smaller components, operating temperatures, and the integrated gearbox and clutch systems. Furthermore, always verify that the JASO rating is "certified" by checking the official JASO website. Uncertified ratings may not reflect genuine adherence to the required standards.

Myth 8: Any Oil Will Do in an Emergency

While in a dire situation in a remote location, using an oil without the correct JASO rating should be a last resort. If you must use a different oil, try to find one with a JASO MA, MA1, or MA2 rating if possible. Avoid mixing oils with significantly higher viscosities than recommended for your motorcycle. Once you have access to the correct oil, it is imperative to perform a complete oil and filter change as soon as possible.

Myth 9: Synthetic Oil Causes Oil Leaks

Modern motorcycles generally do not experience oil leaks when using synthetic oils. However, older motorcycles with worn seals and gaskets might develop leaks after switching to synthetics. The issue isn't the synthetic oil itself but rather the effective cleaning properties of its detergents. These detergents can remove accumulated sludge and deposits that were, in fact, acting as temporary seals. If leaks occur, replacing the worn gaskets is the solution, not reverting to conventional oil, which will likely leak through the same compromised seals.

Myth 10: Forums Are the Best Source of Oil Advice

Online forums and social media can offer a wealth of opinions, but not all of them are accurate or reliable. For definitive advice on the correct oil for your specific vehicle and riding conditions, consulting with oil manufacturers like Motul directly is the most dependable approach. Their technical experts can provide tailored recommendations based on their in-depth knowledge.

Viscosity and Horsepower Loss

It is a well-established principle that engine oil with a higher viscosity (thicker oil) can lead to a reduction in horsepower. This is because the oil pump has to work harder to circulate thicker oil through the engine's narrow passages. This increased resistance puts a greater load on the oil pump, which is essentially another accessory consuming engine power, similar to the alternator or water pump. Using a lower viscosity oil allows the oil pump to operate more easily, freeing up a small amount of horsepower. In high-performance and racing applications, this effect can be significant.

Dyno testing has demonstrated this phenomenon. For example, a high-horsepower Ford Y-Block engine experienced a loss of approximately ten horsepower when switching from a 10W-40 to a 20W-50 racing oil, even when maintaining consistent operating temperatures. This highlights that oil viscosity has a direct impact on parasitic drag within the engine. Further tests on a dyno mule confirmed these findings, showing a measurable horsepower drop with higher viscosity oils. While the difference between some oils within a similar viscosity range might be small, the impact of significantly thicker oils is undeniable.

The tests also underscored the importance of oil condition. An older, degraded 10W-40 conventional oil showed a significant drop in oil pressure at higher RPMs, indicating a breakdown in its lubricating properties. This not only compromises engine protection but can also affect performance. The testing revealed that oil can indeed wear out and lose its viscosity, necessitating timely oil and filter changes. While dyno pulls provide a controlled environment, they offer a strong indication of how oil degradation can impact real-world performance and engine health.

Key Takeaways:

• Synthetic oils can offer enhanced engine protection and, in some cases, slight horsepower gains.
• Always follow your manufacturer's recommendation for oil type and viscosity.
• Never use automotive oil in motorcycles due to differences in formulation for clutches and gearboxes.
• Verify JASO certification for motorcycle-specific oils.
• Higher viscosity oils can lead to a noticeable horsepower reduction due to increased parasitic drag.
• Regular oil and filter changes are crucial to maintain optimal performance and protection.

Frequently Asked Questions:

Q1: Can synthetic oil damage my engine?

A1: No, if used as recommended by the manufacturer. Modern engines are designed to work with synthetic oils, and they offer superior protection.

Q2: Is it safe to mix synthetic and conventional oil?

A2: Yes, it is safe to mix them, and many blends are available. However, for optimal performance, it's best to use a single type of oil.

Q3: Does a lighter oil mean more horsepower?

A3: While lighter oils reduce parasitic drag, potentially freeing up a small amount of horsepower, they may not offer adequate protection in all conditions. The correct viscosity for your engine is paramount.

Q4: How often should I change my synthetic oil?

A4: Always consult your owner's manual. However, synthetic oils generally allow for longer drain intervals compared to conventional oils.

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