Southwest Synthetic Oils, L.L.C.
Direct Jobber
Servicing Arizona
(520) 444-2634


A wide selection of both gasoline and diesel fuel additive products designed to increase equipment performance and reduce fuel consumption. 

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Do Fuel Additives Work?

Store shelves are littered with fuel additives that claim to provide a number of benefits, including…

• Increased fuel economy
• Smoother engine operation
• Reduced emissions
• Extended engine life
��� Maximum horsepower

Do fuel additives 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.

One reason is, while most motorists expect to experience 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 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.

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 some period of 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.

Additive concentration matters

It takes a fuel additive formulated to the correct concentration to deliver immediate results. And the fact is, most additives on the market simply don’t contain a sufficient concentration of cleaning agents to provide immediate results.

That’s where AMSOIL is different.

P.i. Performance Improver, for example, is one of the most potent gasoline additives on the market today. It does an excellent job cleaning deposits to improve fuel economy up to 5.7% and an average of 2.3%. It also reduces emissions.

Our technical study provides all the details you could ever want, and probably a few more. Or, simply take a look at the before/after images shown here and you can see the dramatic results after just one tank of fuel treated with P.i.

Don’t forget the diesel 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 seven points for maximum horsepower, increased fuel economy and easier starts in all diesel engines.
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.

Fuel Additives

Shop the AMSOIL online store for our gasoline fuel additives - engineered to restore peak performance, reduce emissions and deliver improved fuel mileage. Fuel Injector Cleaner

Shop the AMSOIL online store for our diesel fuel additives - engineered to improve performance, fuel efficiency, and longevity of diesel engines while also reducing deposits and enhancing cold weather operation.

AMSOIL Warranty

AMSOIL guarantees the performance of its products, so you can be confident they perform as advertised. AMSOIL introduced the world’s first API-qualified synthetic motor oil and has since introduced a full line of industry firsts. For more than 40 years, AMSOIL synthetic lubricants have proven themselves in the lab, on the racetrack and on the highway.



 (520) 444-2634

  3560 Country Club Drive 
Show Low, AZ 85901
United States
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