Synthetic oil is better than conventional oil when it comes to its form and function. Conventional oil could never stand up to synthetic when it comes to longevity and ability to handle extremely high temperatures. That’s why you see full synthetic oils in all race cars.
Conventional and synthetic oils begin in the ground. But that’s where the similarities end. Synthetic oil is not only refined but also distilled, purified and broken down into its basic molecules. This process not only removes more impurities from the crude oil but also enables individual molecules in the oil to be tailored to the demands of modern engines. These customized molecules provide higher levels of protection and performance than conventional oils. This creates an oil that produces less resistance in the engine and, therefore, allows more horsepower and overall engine efficiency (i.e., burns less gasoline). In addition, it has a lower volatility which resists vaporization out of the exhaust. But the synthetic base oil is only half the story. The correct blend additives must go into the mix to create the oil.
Depending on where you drive (dusty, dirty climates), and how much and far you drive (shorter distances don't heat oil enough to boil off condensation in the engine), you can probably last between oil changes between 10,000 to 15,000 miles with some brands of synthetic.
There is a middle choice to make things even more confusing, the synthetic blend. This mixes the two together to give you a moderately better oil at better cost to you. These don't quite have the longevity of the full synthetics, so it really all comes out in the wash in the end.
If you want to be on the safe side, you should follow what Dodge recommends (see below) as far as oil goes. In general, high performance engines, like the 5.7, 6.1, 6.2 and 6.4 Hemis require synthetic because of the high heat that builds in these engines, whereas conventional engines don't require anything special.
Here’s how all that chemistry translates to the real world:
Keeps your Engine Cleaner
As oil circulates through your engine it can pick up deposits. Over time, conventional oils can sometimes form sludge, which can reduce your engine's efficiency and, ultimately, reduce the life of your engine. Synthetic motor oils contain fewer impurities compared to conventional motor oils and can better resist the formation of sludge thereby preventing deposits from forming in your engine.
Offer Greater Engine Wear Protection
Engine parts are in constant contact with each other. Only a microscopic film of oil separates metal surfaces in your engine from touching and causing wear. The lubricity of synthetics is like Slick 50 without the moly and other additives. Synthetic motor oils form a more durable fluid film than conventional oils due to their resilient base oils. They reduce wear and help you maximize engine life. It must be remembered that your motor oil is the protective film between hundreds of parts moving at high speeds in an extreme environment (e.g., crankshaft, connecting rods, pistons, intake valves, exhaust valves, camshaft, lifters, push rods, rocker arms, oil pump, etc.) As conventional oils break down, their ability to prevent engine wear diminishes. Synthetics, on the other hand, retain their wear protection properties for a much longer time, increasing engine life.
Flow Better in Low Temperatures
When your car sits for awhile (let’s say overnight) the oil settles. But, when you fire up the ignition, it begins flowing through critical engine parts to protect against friction. With conventional oils, it takes more time until they are able to flow smoothly through the engine. During the cold winter months, or if you live in an extremely cold environment, this flow process takes even longer. When the temperature drops, motor oils thicken and move slower, causing parts of your engine to remain unprotected for a short period of time. Synthetics, especially 0W-40 weight, are engineered to flow quickly even at low temperatures, and start protecting your engine as soon as you start your engine. This means the oil can reach vital components faster, providing more immediate engine protection and reduced wear at up to -40°F. This also allows your engine start easier and less strain on the starter and find a cooler running cooling system.
Protect Better at High Temperatures
When running, engines are hot, especially Hemi engines. Over time, the high temperatures in your engine can cause conventional motor oils to break down or evaporate exposing your engine to wear. Synthetics are engineered to resist these high temperatures, which is especially important if you’re driving in hot climates or racing. In order to keep on pace with the increasingly strict fuel economy standards, vehicle manufacturers are designing engines differently, causing them to run hotter than ever before. Hemi engines have a 203°F thermostat. This heat can quickly break down the oil and cause oxidation, sludge and deposits. Synthetics can keep engines up to 81% cleaner than conventional oil by better resisting the formation of these deposits.
Maximizes Fuel Economy
The base oils used in conventional oils contain molecules of different sizes and weights, as well as unwanted materials, like wax. This typically requires more energy to circulate throughout your engine, which can reduce fuel economy. Conversely, synthetic motor oils are formulated using molecular uniform synthetic base oils that slip easily over one another and are free of unwanted materials. They help reduce energy lost to friction and maximize fuel economy. Because of their capacity to reduce friction, synthetic engine oils offer increased fuel mileage.
Protects Critical Turbocharger Parts
To meet consumer demand, some automakers are building cars with smaller engines (for greater fuel efficiency) with turbochargers. The shaft inside a turbocharger can spin upwards of 200,000 revolutions per minute, so it’s critical that your motor oil can get to that shaft and lubricate it properly very quickly. Conventional oils can break down faster under these conditions and leave deposits on turbocharger components, which can lead to failure. Synthetic motor oils can protect these components much better than conventional oils, keeping them operating at peak performance and boosting your engine’s power.
Dodge recommends Mobil 1 0W-40 synthetic oil for all 6.1 Hemi engines. Mobil 1 advanced full synthetic motor oils deliver exceptional performance and protection for vehicles of all ages and for all driving conditions- normal to extreme. (Note- Mobil 1 is the official motor oil of NASCAR through 2022).
Mobil 1 oils keep engines running like new by helping:
*Combat sludge and deposit buildup.
*Control oil breakdown.
Mobil 1 motor oils offer a full range of temperature protection: For cold starts, the oil keeps flowing as low as -40°F, and it can withstand high temperatures of up to 500°F.
For the 6.4 (392) and 6.2 (supercharged) engines, Dodge recommends Pennzoil Ultra Platinum 0W-40. The 5.7L requires 5W-30 for non MDS engines and 5W-20 for MDS engines. Pennzoil Ultra Platinum Full Synthetic Motor Oil delivers complete protection:
*Better Fuel Economy.
*Horsepower Protection: Helps protect engines from loss of power.
*Unsurpassed Wear Protection: No other leading motor oil provides better protection from friction. It is backed by the Pennzoil lubrication limited warranty exceeds the most stringent car manufacturer's requirements for cleanliness and protection. It contains special protective additives for superior engine protection that exceeds USA and European industry standards like ILSAC GF-5, API SN and ACEA performance.
*Excellent Performance in Extreme Temperatures: Provides faster low temperature oil flow and protects in extreme heat.
*Outstanding cleaning: Pennzoil Ultra Platinum Full Synthetic engine oil with superior active cleansing agents continuously attacks potential and stubborn deposits to help keep the engine clean. It is designed to provide superior cleansing under the most severe driving style or conditions to maximize engine responsiveness. Its active cleansing agents, keeps pistons 40% cleaner than the toughest industry standards and cleans out engine sludge better than conventional oils.
Note- Conventional 5W-30 oil is recommended for Challengers with the 3.5 or 3.6L engines. Although, not necessary, synthetic oil may be used.