We all have tough questions about gasoline quality, and what’s right for our car. Helping you understand how fuels and lubricants work is what we’re all about. And we know that once you understand exactly how our quality petroleum products are made, you’ll love CITGO even more.
Here are some of the questions we hear the most.
What is gasoline?
Is your gas really “good?” Why should I feel comfortable choosing CITGO gas?
Who uses CITGO gas?
What is ASTM?
Your gas meets ASTM specifications. What does that mean for my car?
What processes do you use in overseeing the fuel that ends up at my CITGO station?
What about ethanol? What does it do to my engine and what does CITGO do to ensure that I get the best specifications on the ethanol in CITGO gas?
What is meant by Octane?
What is engine knock?
What causes engine knock, and how can I prevent it?
So, which gasoline octane grade should I use in my car?
If I use the appropriate octane grade for my car, why do I also need a detergent additive?
Is your detergent additive available in all octane grades?
What is Reformulated Gasoline?
Will Reformulated Gasoline work in my car?
How will using Reformulated Gasoline affect my car’s fuel economy?
Can I use RFG in my off-road equipment such as a snowmobile, weed trimmer, chain saw, or boat motor?
Q: What is gasoline?
A: In general, gasoline is a complex mixture of many components, called hydrocarbons, which are refined from crude oil. These hydrocarbons are blended together to produce a fuel that’s used to power spark ignition, internal combustion engines. The recipe used for blending these hydrocarbons may vary from refinery to refinery. Finished gasolines, however, are required to meet certain specifications as defined by federal and state regulations and the American Society for Testing and Materials (ASTM).
Q: Is your gas really “good?” Why should I feel comfortable choosing CITGO gas?
A: CITGO is committed to providing quality fuels to you. Because we take product quality seriously, we have adopted that commitment as a company standard. CITGO produces gasoline to strict standards and monitors the quality of our fuel throughout the distribution chain. We believe that you want a reliable, high-quality fuel at a reasonable cost to meet the performance needs of the engine. That is what we deliver in all grades of CITGO gasoline.
Q: Who uses CITGO gas?
A: CITGO has many loyal customers driving a wide variety of vehicles, with a similarly wide variety of engines, who desire a competitive, quality product. What your engine needs is a reliable energy source that allows it to perform well. We guarantee that CITGO gasoline provides a competitive, quality product.
Q: What is ASTM?
A: The American Society for Testing and Materials (ASTM) is an organization made up of voluntary representatives from automobile manufacturers, equipment manufacturers, gasoline producers, and pipeline companies. Through this organization, specifications are developed for gasoline in order to provide a product which will provide satisfactory performance, under varied operating conditions, for all automobiles.
Q: Your gas meets ASTM specifications. What does that mean for my car?
A: It means that our gasoline complies with rigorous standards developed through an independent industry organization whose focus is to ensure that products achieve what they are designed to do. Some of the best technical minds in the industry participate in the ASTM, formerly known as the American Society for Testing and Materials, and influence the way that products are defined as fit for purpose.
For your car, it means that gasoline conforming to ASTM standards, like CITGO gasoline, should provide reliable service for your transportation needs. Gasoline that does not meet the ASTM standard could result in unsatisfactory performance.
Q: What processes do you use in overseeing the fuel that ends up at my CITGO station?
A: CITGO owns and operates bulk storage facilities, also known as terminals, that receive and store fuel prior to its transport to gasoline stations. At these CITGO-controlled terminals, there are ongoing and established programs designed to monitor product quality. For example, our routine oversight includes checking fuels prior to distribution to gasoline stations to determine whether the fuel has changed in transit, possibly rendering it “unfit” or “unsuitable.” Any fuel not in compliance with our standards is isolated within our system. To further ensure product quality, samples of the products in storage are routinely collected and sent to the CITGO quality monitoring laboratory for testing and verification for compliance to standards. These test results are reviewed by fuels technical specialists who discontinue distribution of any product that does not comply with CITGO standards.
In addition to the terminals, CITGO has established programs to monitor product quality at all of our branded gasoline locations. The test results are reviewed by fuels technical specialists for compliance with applicable specifications. In the event that a gasoline does not comply, CITGO instructs the gasoline distributor to discontinue distribution of the fuel and take corrective action.
Q: What about ethanol? What does it do to my engine and what does CITGO do to ensure that I get the best specifications on the ethanol in CITGO gas?
A: Gasoline containing ethanol in concentrations up to 10 percent has been determined by auto manufacturers to be a satisfactory fuel for most late model vehicles. CITGO recommends, however, that you consult your owner’'s manual before using ethanol-blended fuel to ensure that your equipment is compatible with this type of fuel. Furthermore, vehicles operating on gasoline containing ethanol may experience a decrease in fuel economy due to the lower energy content of ethanol.
CITGO is a recognized leader for our efforts in ensuring the quality of ethanol used for blending with gasoline. CITGO earned that role through its continued focus on quality and, consequently, successfully led the ASTM to develop a new ethanol specification limit that ultimately provides additional protection for consumers. The ASTM adopted the new standard as defined and championed by CITGO in what many in the ASTM have declared to be record time. Subsequently, CITGO received an award from the ASTM for successfully moving this issue to completion. In addition, General Motors recognized CITGO for our commitment to quality fuels and the motoring public. That doesn’t happen every day! It is a reflection of our commitment to you.
Q: What is meant by Octane?
A: The Antiknock Index, commonly referred to as Octane, is a measure of a gasoline’s ability to resist preignition, or engine knock. The Antiknock Index posted at the retail pump, such as 87 Octane, is the result of a formula which most closely depicts the average resistivity of the gasoline to engine knock. This average is displayed on the gasoline pump with a sticker showing (R+M)/2 Method.
The Research Octane Number, or R in the equation, is a measure of the gasoline’s ability to resist knock at low speed under relatively mild operating conditions, such as city type driving. The Motor Octane Number, or M in the equation, is a measure of the gasoline’s ability to resist knock at high speeds and under severe operating conditions, such as towing a boat or climbing steep hills. The average of these two numbers defines how well the gasoline will resist engine knock under most conditions.
Q: What is engine knock?
A: Engine knock is a sharp metallic noise, sometimes referred to as engine clatter or pinging, caused by the pre-ignition of fuel as it’s compressed in the cylinder, milliseconds before the normal spark plug firing. This condition typically occurs during acceleration, such as merging into highway traffic, or under heavy load conditions, such as pulling a boat or travel trailer. Under knock conditions, a vehicle will experience a reduction in power output as well as reduced fuel economy.
Q: What causes engine knock, and how can I prevent it?
A: Several factors can contribute to, or result in, engine knock. These factors include outdoor temperature extremes, altitude, humidity, operating under heavy engine loads, time elapsed between routine tune-ups, vehicle age, and manufacturing and engineering tolerances. The most common cause of engine knock is improper tuning of the engine, where the engine timing has deviated from the manufacturer’s design specifications. This problem is easily resolved through proper routine maintenance and tune-ups.
As a vehicle’s engine ages, the octane required to prevent knock may increase. This condition is referred to as Octane Requirement Increase, or ORI, and is the result of normal engine wear. In instances where you experience occasional or moderate knocking, your first line of defense is to try a higher octane gasoline to accommodate this Octane Requirement Increase of your engine. Severe knocking, which cannot be remedied by using a higher octane grade of gasoline, demands your authorized mechanic’s attention.
Q: So, which gasoline octane grade should I use in my car?
A: Your first reference should be the vehicle Owner’s Manual. Each automobile manufacturer includes, in the Owner’s Manual, the recommended minimum octane for normal operation of the vehicle. As a general rule of thumb, however, use the octane grade which prevents your engine from knocking or pinging. CITGO provides three different octane grades of gasoline, complete with CITGO’s proprietary high performance detergent additive, to satisfy the needs of a wide range of vehicles and operating conditions.
Q: If I use the appropriate octane grade for my car, why do I also need a detergent additive?
A: Un-additized gasoline can leave harmful deposits in today’s fuel systems, which are technically advanced and highly sensitive to such deposits. Over time, as these deposits accumulate, a vehicle can develop drivability problems such as hesitation, loss of power, poor acceleration, rough idle or even stalling. CITGO’s gasoline detergent additive is formulated to help maintain your car’s engine at peak performance by preventing deposits from forming in critical areas.
Q: Is your detergent additive available in all octane grades?
A: Yes. The benefits of our additive is provided to all of our customers, regardless of the octane grade you choose.
Q: What is Reformulated Gasoline?
A: The Clean Air Act of 1990 identified specific areas in the United States with higher concentrations of air pollutants. To improve air quality, the Environmental Protection Agency mandated that certain of these areas would require Reformulated Gasoline (RFG). RFG is gasoline which has been specifically manufactured to reduce undesirable emissions from vehicles. RFG must meet more stringent specifications compared to conventional gasoline (non-RFG). These more stringent specifications, which also require the addition of oxygenates to the gasoline blend, reduce air pollutants from vehicles. The oxygenates provide additional oxygen in the combustion chamber and thereby result in a more complete combustion of the gasoline.
Q: Will Reformulated Gasoline work in my car?
A: Yes. In fact, all automobile manufacturers have approved Reformulated Gasoline for use in their vehicles.
Q: How will using Reformulated Gasoline affect my car’s fuel economy?
A: While gas mileage is largely affected by driving habits and vehicle maintenance, use of RFG may result in a slight decrease in fuel economy of up to 3 percent.
Q: Can I use RFG in my off-road equipment such as a snowmobile, weed trimmer, chain saw, or boat motor?
A: For such equipment, you should consult the owner’s manual or contact the manufacturer regarding any questions about using RFG.