AMSOIL was founded on innovation, beginning with the introduction of the worlds first qualified synthetic motor oil. By ignoring commonly accepted limitations and refusing to stop short of success, AMSOIL set a new benchmark for lubricant performance. These same principles continue to guide our product development, resulting in Signature Series Synthetic Motor Oil. Signature Series is not only the best oil AMSOIL have ever made, it’s also better than any competitor oil we have tested. Some may claim that Signature Series is over-engineered. Perfect. It’s not for everyone. It’s for those who want the absolute best engine protection — and it delivers.

Protects Against Engine Wear

Signature Series synthetic motor oil develops a strong fluid film that keeps metal surfaces separated. Its robust anti-wear additives further reduce wear in metal-to-metal contact regions for maximum engine life. The Sequence IVA Engine Test, which must be passed to meet the API SN Plus specification simulates extended periods of stop-and-go driving. For 100 hours, the test engine cycles between 50 minutes of idling and 10 minutes of elevated rpm — conditions that encourage engine wear. The camshaft is then measured for wear in 84 locations and an average score is determined.

AMSOIL used Signature Series 0W-20, the lightest viscosity in the line, to further increase the severity of the test. AMSOIL Signature Series Synthetic Motor Oil provided 75% more engine protection against horsepower loss and wear1 than required by the industry standard, extending the life of vital components like pistons and cams.

Protects Pistons from Low Speed Pre-Ignition

AMSOIL armed Signature Series with an advanced detergent system that protects against harmful deposits and low speed pre-ignition (LSPI). Most new engines feature gasoline direct injection (GDI), often combined with a turbocharger to boost power and improve fuel economy. These new technologies, when combined with a poorly formulated motor oil, promote LSPI and threaten engine operation. LSPI is the spontaneous ignition of the fuel/air mixture prior to spark-triggered ignition. It occurs in today’s advanced engines and is much more destructive than typical pre-ignition. A properly formulated motor oil is critical for protecting your engine.

Original equipment manufacturers (OEMs) like GM* have addressed the issue by designing tests to determine a motor oil’s ability to prevent LSPI. Signature Series Synthetic Motor Oil achieved 100% protection against LSPI in the engine text required by the dexos1 Gen 2 specification - zero occurrences were recorded throughout five consecutive tests.

Protects Turbochargers

AMOIL's unique synthetic formulation is inherently stable to resist oxidation and neutralise acids. Signature Series motor oil provides outstanding protection against deposits common to high-temperature engine environments. The tremendous heat and stress turbos create can cause some oils to break down and form harmful bearing deposits through a process known as turbo coking. Over time, turbos can suffer reduced performance or fail altogether.

AMSOIL challenged Signature Series to the GM Turbo Coking Test, which consists of 2,000 cycles of extreme heat soaks. An oil must limit the temperature change within the turbocharger to 13% or less to pass the test. Signature Series limited the temperature increase to only 3.6%, protecting the turbocharger 72% better than required by the GM dexos1 Gen 2 specification.

Maximum Cleaning Power to Battle Sludge

AMSOIL Signature Series Synthetic Motor Oil has 50% more detergents to help keep oil passages clean and promote oil circulation. Engine failures due to sludge are often caused by a plugged oil pick-up tube screen — the motor is effectively starved of oil. The Sequence VG Engine Test measures an oil’s ability to prevent sludge. During the test, a Ford* 4.6L engine is subjected to sludge-inducing conditions for 216 hours. The industry standard allows for 10% blockage before the motor oil fails the test. Signature Series produced a screen virtually free from sludge. Its detergent and dispersant additives are so effective, Signature Series provides 90% better protection against sludge.

Superior Wear Protection

An independent lab compared AMSOIL synthetic motor oil head-to-head against a leading competitor in a 100,000-mile test. AMSOIL provided far superior wear protection and kept bearings looking like new.

Preserves Horsepower

The extreme durability of Signature Series Motor Oil helps your engine run stronger, for longer. We installed Signature Series 5W-30 Synthetic Motor Oil in a Ford* F-150* with a new 3.5L Ecoboost* engine to test its ability to protect turbocharged direct-injection (TDGI) engines from torque and horsepower loss during extended drain intervals up to 25,000 miles (40,200 km). Power sweeps were done at the beginning and end of the test to evaluate horsepower and torque retention. As the graph shows, Signature Series helped maintain engine performance throughout the 100,000-mile (160,934 km) test.

Keeps Pistons Cleaner

AMSOIL formulated Signature Series with superior thermal durability that resists breakdown and keeps pistons clean. The Sequence IIIH Test uses the Chrysler* 3.6L Pentastar* engine to evaluate a motor oil’s ability to resist heat and keep pistons clean. The test is conducted with oil temperatures of 304ºF (151ºC), much hotter than normal operation, to accelerate oil thickening and deposits. A single-length 90-hour test didn’t even challenge Signature Series. Its viscosity was like that of new oil, and the pistons were still nearly spotless. To really test the oil, AMSOIL told the lab to reassemble the engine and run the test again using the same oil. Even after doubling the length of the industry-standard test, the oil limited oil thickening to well under the allowable threshold while delivering 40% cleaner pistons than required by the standard.