Castrol Edge vs Valvoline Full Synthetic SynPower

Both these oils are synthetically formulated for gasoline engines where Edge focuses on wear reduction while SynPower provides better engine protection.

Edge is a catalytic-friendly oil that has a high resistance against breakdown at high temperatures. This decreases the volatility and consumption of the oil, allowing it to provide better fuel economy. It has various anti-wear additives to fight against wear and tear inside the engine. It is known for providing long oil drain intervals.

SynPower has strong detergents and dispersants to keep the engine clean by preventing the formation and build-up of sludge. It has viscosity modifiers to allow excellent performance during high temperatures. There are pour point depressants (PPDs) available in it to keep the oil from getting thick quickly during cold weather.

Side By Side Comparison:

DescriptionsCastrol Edge (5W-30)Valvoline Full Synthetic SynPower (5W-30)
Type of oilFully SyntheticFully Synthetic
Viscosity grades0W-16, 0W-20, 5W-20, 5W-30, 5W-40, 10W-30, 10W-400W-20, 5W-20, 5W-30, 5W-40, 10W-30
ACEAA1/B1, A5/B5A1/B5
Oil Change Interval (Miles)60003000 to 4000

Higher Temperatures Performance

Viscosity is the internal resistance to the flow of an oil while kinematic viscosity is the resistance during the flow caused by the force of gravity. The viscosity index tells us about the resistance of oil against the viscosity changes initiated by temperature variations.

At a medium temperature of 40° C, the Edge performs better since its kinematic viscosity is higher. This means that it will resist highly against the flow, causing it to not get thinner and maintain its lubricating properties.

Whereas the SynPower wins at an extreme temperature of 100° C with a narrow margin from the other oil and since it was better able to resist a decrease in its kinematic viscosity due to temperature increase, therefore, its viscosity index is higher.

Motor Oils (5W-30)Kinematic Viscosity at 40° C (cSt)Kinematic Viscosity at 100° C (cSt)Viscosity Index
Castrol Edge62.510.7161
Valvoline Full Synthetic SynPower61.610.8168

Lower Temperatures Performance

Just as the temperature starts to fall below the zero-degree Celsius marks the wax crystals start to form inside the oil. These crystals make the oil thicker and increase its dynamic viscosity which is the resistance to flow under the influence of an external force. Such oils will freeze quickly, having a lower pour point temperature. Pour point depressants (PPDs) are added inside the oil to avoid the quick buildup of wax crystals.

Edge has a higher dynamic viscosity, indicating a higher crystal build-up and lower quantity of pour point depressants (PPDs). This oil will freeze quickly in cold weather and will perform poorly.

Whereas the SynPower has a lower dynamic viscosity due to the higher quantity of pour point depressants available in this oil. It will be less thick and will flow better especially in cold engine startup conditions. Its pour point temperature will also be much lower than its counterpart.

Motor Oils (5W-30)Dynamic Viscosity @ -30° C (mPas)
Castrol Edge5544
Valvoline Full Synthetic SynPower4329

Oil Drain Interval

All engine oils are basic in nature as they need base additives to neutralize the acids which get formed as a by-product during the combustion process. A higher quantity of these will allow the oil to maintain the basic nature for a longer interval of time, hence, directly affecting the oil change interval.

Edge has a higher TBN which is the Total Base Number, showing the number of bases inside the oil. Since it has a higher TBN, so, it provides a long oil change interval of 6000 miles while the TBN of SynPower is significantly lesser compared to that of its counterpart. This makes it useable for a shorter duration of period i.e., 3000 to 4000 miles maximum.

Motor Oils (5W-30)TBN (mg KOH/g)
Castrol Edge11.3
Valvoline Full Synthetic SynPower8.4

Reduction In Efficiency of Catalytic Converter

Different oils have variable impacts on the performance of catalytic converters depending upon the concentration of ZDDP compound inside them. This compound gets converted into ash when the oil burns, poisoning the catalytic converter.

In this case, SynPower was tested to be having higher amounts of zinc and phosphorus inside it which are the main constituents of the ZDDP compound. This indicates that it will create a lot of ash when burnt, making it ineffective to be used with the catalytic converters.

While Edge also has a good amount of zinc and phosphorus, but their quantities are lesser in comparison to that of its competitor. This causes it to be relatively effective with the catalytic converters.

Motor Oils (5W-30)The concentration of zinc and phosphorus (ppm)
Castrol Edge1508
Valvoline Full Synthetic SynPower1524

Sludge And Varnishes Removal Ability

Deposits and contaminants pollute the oil as it gets used with time. A build-up of these can hinder the oil from carrying out its duties properly. Therefore, detergents, dispersants, and anti-foam agents are added inside the oil to keep these deposits trapped inside the oil. This causes them to be filtered out or drained instead of sticking together to form sludge or foam under certain conditions.

Edge relies on magnesium to keep the engine clean which is aided by the calcium whose quantity is quite decent. A neglectable amount of sodium is also present but still, all of them combined could not beat its counterpart in terms of varnishes removal. However, its anti-foam ability is better due to a higher amount of silicon anti-foam agent in this oil.

SynPower, on the other hand, takes the lead in this competition of engine cleaning thanks to its gigantic calcium concentration which along with a decent amount of sodium is enough to effectively clean the engine. There is a neglectable amount of magnesium also available in this oil. Whereas its anti-foam ability is a little lower than its counterpart because of its lesser silicon concentration.

Motor Oils (5W-30)Calcium Concentration (ppm)Magnesium Concentration (ppm)Sodium Concentration (ppm)Silicon Concentration (ppm)
Castrol Edge7461462<58
Valvoline Full Synthetic SynPower212574615

Vaporization Rate and Fuel Economy

At high temperatures the molecules of the oil may break down and evaporate, increasing the consumption rate of that oil. The vapors gather on the top of oil until their quantity is enough to support non-continuous ignitions. This is called the liquid’s flashpoint, hence, an oil with a lower vaporization rate will achieve its flashpoint at a higher temperature and its fuel economy will be better.

Edge has a slightly higher high-temperature breakdown resistance, causing its molecules to resist breakdown and decrease its volatility rate. This positively impacts the oil consumption rate which is verified by its higher flash point temperature. Therefore, this oil will provide a better fuel economy.

SynPower is on the lower end of the deal since its high-temperature molecules breakdown resistance is lesser than its competitor, causing its molecules to break and fizzle out in the air. This makes its flashpoint temperature lower, indicating a higher oil consumption and a lower fuel economy.

Motor Oils (5W-30)Volatility rate (⸓)Flash Point Temperature (°C)
Castrol Edge11.1>200
Valvoline Full Synthetic SynPower11.6204

Reduction in Friction

The oil has anti-wear additives to counter the friction inside the engine which is considered the main cause of wear and tear. These additives form a barrier layer atop the metal surface not allowing them to directly slide. This reduces the friction as there is no contact, ensuring there will be less to no wear.

Edge has higher concentrations of all the anti-wear additives except for the phosphorus which is a little lower than that in its counterpart. This causes it to produce a strong and resistant oil film which further decreases the friction and avoids wearing.

While SynPower with just a little higher amount of phosphorus stands seconds, regarding friction reduction since there is no molybdenum and the boron quantity is neglectable. This sabotages the friction reduction abilities of this oil.

Motor Oils (5W-30)Phosphorus Concentration (ppm)Zinc Concentration (ppm)Molybdenum Concentration (ppm)Boron Concentration (ppm)
Castrol Edge6728368076
Valvoline Full Synthetic SynPower699825<14

So to conclude:

  • Both oils can be used with gasoline engines and are fully synthetic.
  • Edge will less decrease the efficiency of the catalytic converter.
  • SynPower is better at reducing the build-up of sludge and varnishes.
  • Edge has a better capability of reducing the friction which causes the wear.
  • The fuel economy of Edge is considered better due to its lower volatility rate.
  • Edge performs better at medium while SynPower at high temperature and has a higher viscosity index.
  • During winters or in cold conditions SynPower will outperform its competitor.
  • Edge allows longer oil drain intervals.
  • SynPower is a cheaper oil.