AMSOIL P.i. is a potent gasoline performance improver with concentrated detergent that aggressively cleans stubborn, power-robbing deposits from injectors, valves and the combustion chamber. Effective in port and direct injection systems. Bottle compatible with capless fuel systems. Cleans entire fuel system in one tank of gasoline. For use with cars and trucks. Treats up to 30 gallons. Add entire bottle to tank at fill-up. For best results, clean your fuel system with P.i. every 4,000 miles (6,400 km). Do not use with diesel or two-stroke engines.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL P.i.® Performance Improver Gasoline Additive.
AMSOIL P.i. is a concentrated detergent-based gasoline performance improver formulated for port-injected and gasoline direct-injection (GDI) engines. One 12 oz. bottle treats up to 30 gallons of gasoline and cleans the entire fuel system in a single tank, making it the right choice for daily drivers, high-mileage commuters, and trucks that have accumulated deposits on injectors, intake valves, and combustion chamber surfaces.
Concentrated detergent chemistry for stubborn deposits
P.i. is built around aggressive deposit-control additives that attack the most common forms of fuel-system fouling, including injector tip carbon, intake valve gum and varnish, and combustion chamber hard deposits. The chemistry works during normal driving as the treated fuel passes through the system, so no shop visit, fuel-rail disconnection, or pressurized cleaning service is required to put the product to work.
Restores GDI injector flow in a single tank
Gasoline direct-injection injectors sit inside the combustion chamber, where heat, pressure, and incomplete combustion drive soot levels 30 to 40 times higher than port fuel injection. Even minor injector fouling reduces flow rate, alters spray pattern, and degrades fuel economy, power, and emissions. Testing in the ASTM D5598(M) procedure on a 2013 Buick Regal restored fouled GDI fuel injectors to a 100 percent flow rate after one tank of P.i.-treated fuel. The product also keeps port fuel injectors clean and free-flowing through normal use.
Restores up to 14 percent horsepower on a high-mileage GDI engine
Third-party chassis dyno testing on a 2016 Chevrolet Silverado 1500 with a 5.3L V-8 GDI engine and 100,616 miles on the odometer measured a 14 percent improvement in horsepower after a single tank of fuel treated with P.i. Disassembly photographs taken before and after the treatment showed visibly reduced deposits on the injectors and cylinder heads, with measurable power gains tied to the cleanup of fouled hardware. Actual results vary with vehicle, mileage, baseline deposit load, and driving conditions.
Cleans intake valves and frees stuck valve stems
Intake valve deposits absorb and release fuel on the back of each valve, disrupt airflow, and can cause valve sticking by interfering with the valve stem and guide. The deposits cost power and efficiency, raise exhaust emissions, and can ultimately contribute to valve failure. P.i. removes intake valve deposits and helps the valves stay clean and move freely, which restores the intended air-fuel ratio and seal.
Reduces combustion chamber deposits, carbon rap, and pre-ignition
Hard combustion chamber deposits raise effective compression and store heat between cycles. In some engines, deposit buildup can grow tall enough that the piston physically contacts the cylinder head, a condition known as carbon rap. The same deposits can flake off and lodge between the valve and seat, causing compression loss, rough idle, and hard starting. Higher stored heat also increases the likelihood of pre-ignition knock or pinging, which the engine controls by retarding spark timing at the cost of power and efficiency. P.i. attacks combustion chamber deposits, helps control knock, reduces the need for costly higher-octane fuel, and restores fuel economy.
Capless-compatible bottle for modern fuel necks
Many newer vehicles use capless fuel-filler systems with a spring-loaded flap behind the neck. The threads on most aftermarket additive bottles can resist the flap and make application awkward. The P.i. bottle is engineered to open and seat fully in capless fuel necks, which makes a clean pour straightforward at the pump.
Recommended applications and service intervals
P.i. is formulated for gasoline-powered cars and light trucks. One 12 oz. bottle treats up to 30 gallons of fuel, so the entire bottle is added to the tank at fill-up. For best results, treat the fuel system with P.i. every 4,000 miles (6,400 km). The additive is compatible with catalytic converters, oxygen sensors, oxygenated gasoline, and E85.
Treat the tank with one full 12 oz. bottle at fill-up; treats up to 30 gallons.
Use for routine maintenance every 4,000 miles to keep injectors, valves, and the combustion chamber clean.
For large gasoline tanks, use two bottles per treatment. Using more than two bottles per treatment is not recommended.
Not for use in diesel engines or two-stroke engines.
P.i. is a gasoline maintenance additive and is not a replacement for a fuel-system rebuild on engines with hardware damage. For fuel stabilization in stored or seasonal equipment, or for ethanol-related issues in small engines and powersports, review the AMSOIL Quickshot Guide to compare product roles before stacking treatments in the same tank.
Order AMSOIL P.i. Performance Improver Gasoline Additive
AMSOIL P.i. Performance Improver Gasoline Additive is available as a 12 oz. bottle (product code APICN-EA) and as a case of twelve 12 oz. bottles (APICN-CA). The product is backed by the AMSOIL Limited Warranty. Confirm the right product for the vehicle with the AMSOIL Vehicle Lookup Guide, compare P.i. with the ethanol-focused powersports additive in the AMSOIL Quickshot Guide, then order AMSOIL P.i. Performance Improver Gasoline Additive.
What does AMSOIL P.i. do that pump-gas detergent does not?
Most pump gasoline contains a baseline detergent dose set to a federal minimum. P.i. is a concentrated maintenance treatment dosed to clean an entire tank in one pass, targeting fuel-injector tips, intake valves, and combustion chamber hard deposits that the baseline detergent in gasoline is not strong enough to remove once they have formed.
How often should P.i. be used?
For best results, clean the fuel system with P.i. every 4,000 miles (6,400 km). One 12 oz. bottle treats up to 30 gallons of fuel and is added at fill-up. For tanks larger than 30 gallons, treat with two bottles. Using more than two bottles per treatment is not recommended.
Is P.i. safe for GDI, turbocharged, and flex-fuel engines?
Yes. P.i. is engineered for both port-injected and gasoline direct-injection engines, and is safe for use with catalytic converters, oxygen sensors, oxygenated gasoline, and E85. It is intended for gasoline-powered cars and light trucks; it is not for diesel engines or two-stroke engines.
How quickly does P.i. work?
P.i. cleans the entire fuel system in one tank of gasoline. In ASTM D5598(M) testing on a 2013 Buick Regal, fouled GDI fuel injectors were restored to a 100 percent flow rate after a single tank of P.i.-treated fuel. Third-party chassis dyno testing on a 2016 Chevrolet Silverado 1500 5.3L GDI with 100,616 miles measured a 14 percent horsepower improvement after one tank.
Can P.i. be added to a partially full tank?
P.i. is dosed to clean up to 30 gallons of fuel per bottle, so the cleanest result comes from adding the entire bottle at fill-up so the treat rate matches the gasoline volume. A partially full tank still benefits, but the treat rate is richer than necessary, and the next fill-up of untreated fuel will dilute the remaining additive in the tank.
Will P.i. reduce engine knock and the need for higher-octane fuel?
Combustion chamber deposits raise effective compression and store heat between cycles, which increases the likelihood of pre-ignition knock. P.i. attacks those deposits and helps restore the engine to its designed compression behavior, which controls knock, reduces noise from carbon rap, and reduces the need for costly higher-octane fuel as the vehicle accumulates miles.
Does using AMSOIL P.i. affect a new-vehicle warranty?
No. Using AMSOIL products does not void a new vehicle or equipment manufacturer warranty, and AMSOIL products are backed by the AMSOIL Limited Warranty.
