• Restores up to 14% horsepower1
• Restores GDI fuel injectors to 100% flow rate after one tank of fuel2
• Improves fuel economy
• Reduces need for costly higher-octane fuel
• Helps prevent carbon rap
• Controls pre-ignition knock
• Compatible with capless fuel systems
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.
Package sizes include:
12-oz. Bottle
12-oz. Bottles (case of 12)
AMSOIL P.i. features aggressive additives that attack the most common forms of engine deposits and limit their effects.
• Use in gasoline-powered 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.
• For large gas tanks up to 60 gallons, treat with two bottles of P.i. Using more than two bottles per treatment is not recommended.
• Safe for use with catalytic converters, oxygen sensors, oxygenated gas and E85 fuel.
• Do not use with diesel or two-stroke engines.
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.
• Helps keep valves clean and moving freely.
• Aggressive additives attack the most common forms of engine deposits and limit their effects.
• P.i. removes deposits and keeps injectors functioning as they should.
• Testing shows P.i. restored GDI fuel injectors to a 100% flow rate after one tank of fuel.2
Most new engines feature gasoline direct-injection (GDI) to boost power and improve fuel economy. These injectors are located inside the intense heat and pressure environment of the combustion chamber, making them particularly vulnerable to deposits. Extreme pressure combined with incomplete fuel combustion can lead to dramatically increased
soot (particulate matter) levels. Direct injection typically creates 30 to 40 times more soot than port fuel injectors (PFI). Even a minimal amount of injector fouling can lead to increased pollution and wear and decreased power and fuel economy.
Injector deposits:
• Decrease efficiency, power and fuel economy.
• Increase exhaust emissions.
• Contribute to poor starting and rough idle.
P.i. removes stubborn deposits and keeps injectors functioning as they should. Testing shows P.i. restored GDI fuel injectors to a 100% flow rate after one tank of fuel2
• Third-party testing demonstrated performance of P.i. using a 2016 Chevrolet* Silverado* with 100,616 miles on the odometer.
• Following a single treatment with P.i.,
the truck measured an incredible 14% improvement in horsepower.1
We set out to once again demonstrate the superior performance of P.i. through third-party testing using a 2016 Chevrolet Silverado with 100,616 miles on the odometer. Prior to testing, the truck was run on a chassis dyno and horsepower was measured. The 5.3L GDI engine was then disassembled, photographed and reassembled. Following a single tank of of fuel treated with P.i. driving at highway speeds, the truck was again strapped to the dyno. It measured an incredible 14% improvement in horsepower. The engine was then disassembled once again to see the impact P.i. had on deposits. The images to the right demonstrate the powerful cleaning performance of P.i on injectors and cylinder heads to significantly restore power and efficiency.
Valve deposits alter or restrict airflow patterns in the cylinder. They disrupt the balanced air/fuel ratio by momentarily absorbing and releasing fuel. The deposits can also cause valve sticking by getting in the way of the valve stem and guide.
Intake valve deposits:
• Decrease power and efficiency
• Increase exhaust emissions.
• Lead to potential valve failure.
P.i. helps keep valves clean and moving freely.
• Fights combustion chamber deposits to help restore power, control knock, increase fuel economy and reduce the need for higher-octane fuels.
• Protects against compression loss, difficulty starting and rough idling.
• Reduces possibility of
"carbon rap," when deposit buildup causes the piston to hit the cylinder head.
• Decreases the possibility of pre-ignition "knock" or "pinging."
Combustion chamber deposits increase compression and absorb heat during combustion. Later, they release that heat during the intake cycle. In some engines, deposits can cause the piston to actually hit the cylinder head - a process known as "carbon rap". The deposits can also flake off and become trapped between the valves and valve seat, resulting in compression loss.
Higher compression and stored heat increase the likelihood of pre-ignition "knock" when the fuel spontaneously combusts prior to spark ignition. This increases emissions and may cause engine damage. Most vehicles have sensors that adjust spark timing to prevent knock. Although audible "knock" is controlled, power is lost from retarded timing and engine efficiency suffers. Higher octane fuels can be used to help prevent the phenomenon. As a vehicle ages, more
expensive, higher octane fuel is needed to keep it operating at peak performance.
Combustion chamber deposits:
• Increase the possibility of "carbon rap".
• Contribute to compression loss, difficult starting and rough idling.
• Increase the possibility of pre-ignition "knock" or "pinging".
P.i. fights combustion chamber deposits, which helps restore power, control knock, increase fuel economy and reduce the need for higher-octane fuels.
• Bottle is fully compatible with capless fuel systems.
Many new vehicles have replaced traditional fuel caps with capless systems. The threads on most bottles restrict them from opening the flap inside the fuel neck and also make removing the bottle difficult. The P.I bottle is fully compatible with capless fuel systems.
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.
This product is not expected to cause health concerns when used for the intended application and according to the recommendations in the Material Safety Data Sheet (MSDS).
Click here to view the MSDS Data Sheet for AMSOIL API.
Keep out of the reach of children. Don't pollute. Return used oil to collection centers.
Product Name: P.I Performance Improver (API)
Current Rating: 4.9out of 5 stars
Votes & Reviews: 372 vote(s) and 230 user reviews.
Reviewed by Ryan the lion: 
I purchase PI, every oil change. I feel that my 2010 Tahoe dose benefit from this fluid as it's high in mileage and the environment here is harsh for any vehicles. I really don't see any fuel mileage increase, but it's the engine is running smoother in the cold mornings.
It's a nice treat for the "Tank".
Reviewed by Rich:
I used this in one of my older high mileage cars and it seemed to really do what it was intended. I will use this again and probably even in the newer ones.
Reviewed by Hank:
Been using for years. Keeps moisture out and clean injectors
Reviewed by rooroo:
Great product
Reviewed by Dan:
This product works very well and I like using it, however it is expensive which limits my ability to purchase more and use it more ofter.
Reviewed by Dan:
This product works very well and I like using it, however it is expensive which limits my ability to purchase more and use it more ofter.
Reviewed by JMC:
Seem work good additive pi performance gasoline additive with 93 fuel noticed much more effective clean more deep work as great
Reviewed by ironrail:
I use this product every time that I change the oil on my vehicles. I drive about 1000 miles per week so I change my oil frequently. It does what it says that it does. i wish it were already added to the gas at the pumps. My vehicles run as smooth as silk.
Reviewed by John R:
Used this product many times at every oil change all but good results.
Canada
United States
It's a treat
I purchase PI, every oil change. I feel that my 2010 Tahoe dose benefit from this fluid as it's high in mileage and the environment here is harsh for any vehicles. I really don't see any fuel mileage increase, but it's the engine is running smoother in the cold mornings.
It's a nice treat for the "Tank".