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Amsoil 5W-50 Signature Series

Last updated: February 22nd, 2026
Amsoil Signature Series 5W-50 100% Synthetic Motor Oil (AMR)

Amsoil Signature Series 5W-50 is the best synthetic oil money can buy for high horsepower applications requiring a fifty weight oil. This oil will work perfectly in modern high horsepower Ford Mustang's and other high output vehicles. As with all Signature Series products, 5W-50 offers extended drain intervals in regular service driving conditions.

Features And Benefits of Amsoil 5W-50

  • 25,000 mile or one year drain intervals
  • Outstanding protection for turbo and direct injection
  • Industry leading cold weather properties
  • Top of the line product for maximum wear protection

Common Applications:

  • Ideal for Ford Mustang 5.2L Voodoo Engine (GT350 2015 - 2020)
  • Ideal for Ford Mustang 5.2L Predator Engine (GT500 2020 - 2022)
  • Ideal for Ford Mustang 5.8L (GT500 2013 - 2014)

Available Packaging for AMR

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Technical Info PDF

This product will typically ship within 24 hours from one of Amsoils 14 distribution centers in North America. This means that the product will ship to you from the closest possible location and most orders end up arriving in two to three days or less! Expedited shipping options are available as well.

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Performance Tests and Comparisons
100,000 Mile Wear Protection Test
Amsoil 5W-50 Provides world class protection. Amsoil was compared head to head with a leading competitor in a 100,000 mile test and showed superior bearing and wear protection. When measuring average cam wear in the sequence IVA test, Amsoil showed 75% more protection against loss due to engine horsepower and wear!
amsoil wear performance test
View The Wear Protection Test
Low Speed Pre Ignition (LSPI) Prevention Test
Over the course of five tests, Amsoil had zero LSPI events. Low speed pre ignition occurs when there is a premature ignition of the fuel during the combustion cycle. This can result in poor performance, knocking and engine damage.

The image below shows damage that occurred to a piston during the failure of a competitors oil in the LSPI test.

amsoil LSPI test
View The LSPI test
Acid Neutralization Test
Amsoil offers superior acid neutralization qualities when compared to the competition. A powerful detergent additive package gives amsoil 30% more acid protection than Mobil 1 and Royal Purple. The image below shows the total base number of Amsoil after the test, compared to other leading competitors.
amsoil acid neutralization test
View The Acid Neutralization test
Turbo Protection Test
Amsoil Signature Series exceeds GM Dexos1 Gen2 turbo charger protection requirements by over 70%. Amsoil protects against sludge, deposits and other performance robbing deposits on the turbo shaft. Additionally Amsoil showed excellent heat control properties.
amsoil turbo test
View The Turbo Protection test
Oil Volatility Test
Amsoil Signature Series motor oils fight volatility better than both Royal Purple and Mobile 1. Volatility occurs when an engine oil loses weight due to evaporation at normal to high operating temperatures. Amsoil loses the least amount of weight compared to the leading competitors.

The graph below shows that Amsoil only had a 6% loss of volatility during the test. Well ahead of the competition and well below the industry standard. The lower the loss, the better!

amsoil volatility test
View The Volatility test
Applications
Amsoil Signature Series 5W-50 is usable in engines with the following specifications:
  • SN Ford WSS-M2C931-C (Mustang)
  • API SP
  • SN Plus
Amsoil 5W-50 Frequently Asked Questions
A 5W-50 oil flows well during cold starts while maintaining a thicker protective film at higher temperatures. This wide viscosity range helps protect engines that see both everyday driving and occasional high-load conditions. It’s also why certain performance engines, including specific Ford Mustang models, are factory-specified for 5W-50 due to their higher operating temperatures.
Some engines operate with higher cylinder pressures, tighter tolerances, or elevated temperatures. Manufacturers specify 5W-50 to ensure the oil maintains proper viscosity under heat. Ford does this for select Mustang engines because the heavier high-temperature rating helps maintain film strength and reduce wear. Other vehicles may require it for similar thermal-protection reasons.
This synthetic formulation uses advanced base oils and premium additives to resist oxidation, reduce wear, and maintain viscosity stability. Its low volatility helps minimize oil consumption. These benefits apply to any gasoline engine requiring 5W-50, including performance-oriented models like certain Mustangs, where heat resistance and long-term protection are especially important.
Yes. If the manufacturer specifies 5W-50, Amsoil’s Signature Series is an excellent choice for everyday vehicles. Its synthetic formulation improves cold-start flow, reduces friction, and provides strong high-temperature protection. While some performance cars like specific Mustangs require 5W-50, many standard vehicles can also benefit when their OEM recommendations call for this viscosity.
It maintains a strong protective film across a wide temperature range, separating metal surfaces and reducing friction. Its anti-wear additives further protect critical components such as bearings and camshafts. This is valuable in any engine that sees elevated heat, including certain Mustang engines known for higher operating temperatures, but the benefits apply equally to any vehicle requiring 5W-50.
Yes. Its low-volatility formulation resists burn-off at high temperatures, helping reduce oil consumption and emissions. This is especially useful in engines that naturally run hotter or have higher output, such as some Mustang variants, but the benefit applies to any vehicle where minimizing oil loss is important.
Signature Series is engineered for long-drain performance thanks to its oxidation resistance and robust additive system. In mechanically sound gasoline engines, it can support extended intervals under normal service conditions. This applies whether the oil is used in a performance-oriented vehicle like a Mustang or in a standard passenger car that simply requires 5W-50.
It flows easily in cold weather due to its synthetic base oils and lack of wax, improving start-up protection. At high temperatures, it resists breakdown and maintains viscosity better than conventional oils. This makes it suitable for engines that experience wide temperature swings, including certain Mustang engines designed to operate at higher thermal loads.
It is compatible with other synthetic and conventional oils, though mixing reduces its performance advantages and shortens its service life. Aftermarket additives are not recommended because the Signature Series formulation already contains a complete additive package. This guidance applies universally, whether the oil is used in a Mustang or any other vehicle requiring 5W-50.
Always follow the manufacturer’s viscosity recommendation in your owner’s manual. Some vehicles, including specific Ford Mustang models, are factory-specified for 5W-50 due to their operating characteristics. Others may require lighter viscosities. Using the correct grade ensures proper lubrication, wear protection, and performance across all driving conditions.

The Performance Oil Company

An Authorized Amsoil Dealer
Allenton, Wisconsin 53002
(262)-388-3411