Store shelves are littered with additives for fuel that claim to provide a number of benefits, including…
• Increased fuel economy
• Smoother engine operation
• Reduced emissions
• Extended engine life
• Maximum horsepower
Do additives for fuel work, though?
A quick Google search reveals multiple articles that claim they don’t. There must be a good reason so many people regard fuel additives with skepticism.
That’s because, while most motorists expect to see the benefits promised by fuel additives immediately, it takes several tanks of treated fuel before most additives provide any noticeable performance improvement. That doesn’t bode well in a society used to getting what it wants, when it wants it.
Engine condition plays a vital role in fuel-additive performance
Here’s what often happens.
Over time, performance-robbing deposits form on your engine’s fuel injectors, valves and in the combustion chamber. Today’s injectors are highly engineered to tight tolerances, and even minute deposits interfere with the spray pattern and reduce power and fuel economy.
The problem is especially pronounced in high-pressure common-rail (HPCR) diesel engines and in direct-injection engines that locate the injectors in the combustion chamber, exposed to intense heat.
Eventually, you notice a reduction in power, throttle response, fuel economy or drivability. You pick up a fuel additive at the gas station or parts store.
“Increases Fuel Economy!” it proclaims. “Outstanding,” you think as you empty the bottle into your fuel tank.
Are fuel additives one and done?
But, by the time you pull up your driveway, nothing has changed. Or again the next day after you arrive at work. What went wrong?
Technically, nothing. You likely bought an inexpensive additive that contains minimal cleaning agents. If you continue to buy the additive and use it with every tank of fuel, maybe over time – could be weeks to months – you’ll experience a slight up-tick in power, fuel economy or drivability.
Then you can continue to use the additive to maintain engine performance. The additive did, indeed, work and it did live up to its performance claims. It just didn’t do it quickly or dramatically enough.
Fuel-additive concentration matters
It takes a fuel additive formulated to the correct concentration to deliver immediate results. But most additives for fuel simply don’t contain a sufficient concentration of cleaning agents to provide immediate results.
That’s where AMSOIL is different.
P.i. Performance Improver is a potent, deep-cleaning gasoline performance improver featuring concentrated detergents that aggressively clean stubborn, power-robbing deposits from injectors, valves and combustion chambers. It reduces emissions and increases fuel economy up to 5.7 percent.¹
Works in GDI engines, too
It also works well in gasoline direct-injection (GDI) engines. In GDI engines, 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.
P.i. removes stubborn deposits and keeps injectors functioning as they should. Testing shows P.i. restored GDI fuel injectors to a 100 percent flow rate after one tank of fuel.²
How about upper-cylinder lubricants?
Many additives for fuel are marketed as upper-cylinder lubricants. 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. This can lead to ring and cylinder wear that reduces engine compression, decreasing power and performance. In step a range of fuel additives promising vital lubrication for the engine’s top-end, maximizing protection and performance.
Again, though, some additives don’t provide much, if any, lubricity improvement, as the chart shows. AMSOIL Upper Cylinder Lubricant, however, delivers 18 percent more lubricity than Lucas³ and 20 percent more than Sea Foam³ for better retention of horsepower and fuel economy. It also fights ethanol-related corrosion.
Don’t forget the diesel fuel additives
For peak performance, diesel engines need a daily dose of detergent for cleaning and lubricity to protect the injectors and fuel pump while keeping the combustion chamber clean.
- AMSOIL Diesel Injector Clean provides the optimum chemistry to deliver confidence your truck is protected.
- AMSOIL Diesel Cold Flow enhances fuel flow and helps prevent fuel-filter plugging in cold temperatures.
- AMSOIL Diesel Cetane Boost raises the cetane number of diesel fuel up to eight points for maximum horsepower, increased fuel economy and easier starts in all diesel engines.
- AMSOIL Diesel Injector Clean + Cetane Boost combines the superior detergency and improved lubricity of AMSOIL Diesel Injector Clean and the increased horsepower and cetane of AMSOIL Cetane Boost in one convenient package.
- AMSOIL Diesel All-in-One combines the benefits of all three additives in one convenient package. (It also does a great job preventing fuel gelling in cold weather.)
And don’t forget Quickshot for your small engines and powersports equipment. It cleans performance-robbing deposits, stabilizes fuel during short-term storage and fights ethanol problems.
So, yes, fuel additives do work – if you use the right ones.
¹ Based on independent testing using EPA tests: Federal Test Procedure 75 (FTP), Supplemental Federal Test Procedure (US06), and the Highway Fuel Economy Test (HFET). Average fuel mileage increase of 2.3 percent.
² ASTM D5598(M) – 2013 Buick Regal test vehicle
³ Based 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.
Updated. Originally published Jan. 3, 2018.