The One-Two Punch: AMSOIL P.i.® and Upper Cylinder Lubricant

These fuel additives work together to help keep your vehicle running at peak power and performance.

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AMSOIL P.i.® Performance ImproverAMSOIL Upper Cylinder Lubricant
Brad Nelson
by Brad Nelson
November 9, 2023

Carbon deposits and sludge can build up over time, leading to losses in horsepower, performance and longevity. But AMSOIL P.i. and Upper Cylinder Lubricant can thwart those issues with a fierce one-two punch against deposits and sludge. P.i. gives engines an aggressive deep cleaning. Upper Cylinder Lubricant keeps engines clean while lubricating vital components in the top end. Together, AMSOIL P.i. and Upper Cylinder Lubricant provide a comprehensive system to help keep engines running in peak form.


AMSOIL P.i. attacks carbon and sludge buildup head-on with concentrated detergents that aggressively clean stubborn, power-robbing deposits from injectors, valves and the combustion chamber. Third-party testing demonstrated the performance of P.i. using a 2016 Chevrolet* Silverado* with 100,616 miles (161,926 km) on the odometer. Following a single treatment with P.i., the truck measured an incredible 14% improvement in horsepower.1

P.i. restores GDI fuel injectors to 100% flow rate after one tank of fuel.2 It helps keep valves clean and moving freely; helps protect against compression loss, difficult starting and rough idling; improves fuel economy and helps restore power and performance. AMSOIL P.i. reduces the possibility of both “carbon rap,” when deposit buildup causes the piston to hit the cylinder head, and pre-ignition “knock” or “pinging.”

AMSOIL P.i. is effective in one tank of gasoline. Simply add the entire bottle to the tank at fill-up and let it go to work. We recommend treating vehicles with AMSOIL P.i. every 4,000 miles (6,437 km)


AMSOIL Upper Cylinder Lubricant

AMSOIL Upper Cylinder Lubricant helps preserve and build on the gains made by AMSOIL P.i. It maintains cleanliness, particularly in the all-important fuel injectors, lubricates the under-lubricated top end of the engine and fights ethanol-related corrosion. That’s important because an engine’s top end is sparsely lubricated and prone to the development of deposits. It’s also highly susceptible to corrosion, an issue compounded by the prevalence of water-absorbing ethanol in fuel. Upper Cylinder Lubricant features an AMSOIL-exclusive, powerful formulation designed to solve those issues.

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It may seem surprising that a vital region inside modern engines could lack lubrication. But the intense heat of combustion and limitations of the oil-control piston ring result in a lack of oil at the top of each cylinder. Upper Cylinder Lubricant deploys unique additives to provide that missing lubrication and reduce piston-ring and cylinder wear – maximizing engine compression and horsepower. Its lubricity improvers also aid in protecting fuel injectors and other fuel-system components from wear.

And, unlike many competing fuel additives, it actually works. AMSOIL Upper Cylinder Lubricant delivers 18% more lubricity than Lucas* and 20% more than Sea Foam* for better retention of horsepower and fuel economy.3

To battle corrosion, Upper Cylinder Lubricant uses potent corrosion inhibitors that coat metal surfaces, block out moisture and stop deterioration before it starts. This is particularly important when using gasoline that contains ethanol due to its ability to absorb water.

We recommend using Upper Cylinder Lubricant with every tank of fuel. Simply add the entire bottle to the tank when filling up and it will do the rest.

Combined Powers

AMSOIL P.i. and Upper Cylinder Lubricant are two tools every enthusiast should deploy to protect their engines. While AMSOIL P.i. is designed to attack and remove stubborn injector deposits, Upper Cylinder Lubricant helps preserve injector and combustion-chamber cleanliness and provides exceptional top-end lubrication. It’s a one-two punch that can help keep your vehicle running at peak power and performance for many miles to come.



1Based on third-party testing in a 2016 Chevrolet* Silverado* 1500, 5.3L V-8 GDI with 100,616 miles, using one tank treated with AMSOIL P.i. Actual results may vary.

2ASTM D5598(M) – 2013 Buick Regal test vehicle.

3Based on independent testing of AMSOIL Upper Cylinder Lubricant, Lucas Upper Cylinder Lubricant and Sea Foam Motor Treatment obtained on 02/13/2019 using the ASTM D6079 modified for use with gasoline.


by Brad Nelson

Brad Nelson is a staff writer for AMSOIL. Outside of work he enjoys family adventures, wilderness exploration and riding/wrenching on vintage metric motorcycles.

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AMSOIL P.i.® Performance ImproverAMSOIL Upper Cylinder Lubricant

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