FAQs: Fuel Additives

Gasoline additives. Fuel Additives
1. What is the difference between the old 12 oz. STP Fuel Additives and the new 5.25 oz. Fuel Additives? Does the smaller bottle have the same strength?

The new STP Fuel Additive size works just as well as the old size and still treats up to 21 gallons. All the power/performance in an easier to use package.

2. What is the fuel system?

A system that consists of the fuel tank, fuel lines, fuel pump, fuel filter and fuel injectors or carburetor. This system provides for gasoline storage in the vehicle, filters out particles, delivers it to the intake air system and mixes the air and gasoline, in the correct ratio, so it can be efficiently burned in the engine.

3. What are fuel injectors?

Electrically operated valves that inject a fine spray of fuel, in the proper amount, into the intake port of the engine. The amount of fuel sprayed into the engine varies with engine temperature, speed and load and is controlled by the vehicles onboard computer.

4. What is the combustion chamber?

The place in the engine between the cylinder head and the top of the piston where the fuel/air mixture is compressed by the piston and ignited by the spark plug.

5. Why do I need STP® Gas Treatment or STP® Fuel Injector & Carburetor Treatment?

These fuel additives are referred to as “Keep Clean” products. Just as brushing your teeth keeps harmful bacteria from building up on your teeth, STP® Gas Treatment and Fuel Injector & Carburetor Treatment help keep harmful deposits from building up in your engine’s fuel intake system, including fuel injectors and carburetors. It is important to keep your fuel system free of deposits in order to maintain maximum performance. These STP® products do not remove existing deposits. (See STP® Super Concentrated Gas Treatment, STP® Super Concentrated Fuel Injector Cleaner, STP® Octane Booster and STP® Complete Fuel System Cleaner for “Clean Up” products that help remove existing engine deposits, to restore lost performance and efficiency).

6. Why do I need the STP® Super Concentrated products? (STP® Super Concentrated Gas Treatment and STP® Super Concentrated Fuel Injector Cleaner)

These fuel additives are referred to as “Clean Up” products and will dissolve harmful deposits that may accumulate in your fuel system (including fuel injectors, intake valves and carburetor). These are all sensitive parts of the fuel system that control the fuel/air mixture and must remain deposit-free in order to work properly. By removing deposits in your fuel system, you can restore your vehicle to its optimum performance level, help maximize fuel efficiency, decrease hard starts, restore lost acceleration and decrease rough idling.

7. Why do I need STP® Complete Fuel System Cleaner?

STP® Complete Fuel System Cleaner is our most powerful fuel system cleaner. It not only does the job of our Super Concentrated products, but it also cleans the combustion chambers. The fuel system has a demanding job of delivering the proper fuel and air mixture to the engine, to give you the performance you need. Cleaning it twice a year will result in peak engine performance by restoring lost power and acceleration, maximizing fuel efficiency by cleaning fuel injectors and carburetors and reducing hard starts, engine hesitation, and knock and ping.

8. Why do I need STP® Octane Booster?

All engines develop combustion chamber deposits that can lead to your engine needing higher-octane gasoline than recommended by the manufacturer to operate efficiently. This concept is known as Octane Requirement Increase; or ORI for short. This can cause the "knocking and pinging" sounds you may hear when accelerating. The problem is that knocking and pinging may not be audible to the driver, due to many modern engines being equipped with knock sensors. These sensors detect knock and adjust the vehicles timing to make it stop. These adjustments lead to a quieter engine, but do come at a cost, since they can result in slower acceleration and poor fuel economy. STP® Octane Booster helps remove the power robbing combustion chamber deposits to reduce your engine’s appetite for higher-octane gasoline, reducing knocking and pinging and restoring lost performance.

9. How often should I use fuel additive products?

The STP® fuel additive products are individually labeled for dose and treatment intervals. This information can be found on the back and neck labels of the bottle.

10. How much will STP® fuel additive products treat?

The STP® fuel additive products are individually labeled for proper dosage. This information can be found on the back label of the bottle. Typically, our products treat between 14-21 gallons.

11. Why do some car manufacturers recommend against the use of fuel additives in my car?

Many car manufacturers state that after-market fuel additives are not necessary even though they sell their own brand of fuel additives. Some after-market fuel additives contain corrosive chemicals that may be harmful to fuel system components or internal engine parts. STP® products do not contain any corrosive components such as alcohols and are safe for use in all engines.

12. Are STP® products safe for diesel engine systems?

STP® has specially designed products for diesel engines and has labeled them as diesel products. They have been thoroughly tested in specific diesel applications.

13. Are STP® products safe for four-cycle engines?

The STP® fuel additive products are specifically designed for use in four-cycle engines.

14. Are STP® products safe for two-cycle engines?

The STP® fuel additive products have not been tested for use in two-cycle engines. Therefore, we do not recommend that they currently be used for two-cycle applications.