Is 93 Octane Is Best For Your Mustang?
Last Updated: May 26, 2021
You've no doubt heard the term “high - octane” and when you do, you probably think of some sort of extreme sport that gets your heart pumping and your pulse racing.
Yes, the term “high - octane” is applied to everything from super-caffeinated coffee to ultra-strong liquor that's better used as paint thinner than as a drink. If you're a gear head like the team here at Steeda, there's no doubt you subscribe to the “high-octane” lifestyle but do you put high-octane fuel into your Mustang?
For performance cars like the Mustang, high-octane fuels are necessary to produce the kind of power you expect, and their power ratings are often achieved on 93 octane fuel. The story gets a little more confusing because 93 octane fuel is not universally offered throughout the United States. So, what gives? Is 93 octane necessary to achieve the most power?
The short answer is, yes but don't worry, we'll explain everything you need to know about the often-misunderstood world of 93 octane and pump gas.
What Is An Octane Rating?
When you pull into a gas station, you're presented with three octane levels that you can put into your Mustang. Depending on your state, these ratings range from 85 to 93 octane, but more typically 87 octane to 93 octane is found at stations around the country.
In short, simple, layman's terms; an octane rating is a measure of how much compression the fuel can handle before igniting. Air and fuel are compressed in the cylinder and ignited by a spark that pushes the cylinder down - which moves the crankshaft - which propels your Mustang. Since many performance cars utilize a high compression ratio in their engines, the high-octane rating is required to achieve the engineered result. Running a low octane fuel in a vehicle that requires a high-octane fuel can lead to loss of power and in some cases damage to the engine.
This scenario of early detonation is known as engine knock and it's not a good thing but modern cars have ways of dealing with knock to mitigate damages. Older cars, however, do not have such fancy fail-safes.
87 vs 93 Octane Gas: What's The Difference?
So, 93 octane has a higher resistance to denotating under compression than 87 octane fuel. So what?
Using the 5.0L Coyote in modern Mustangs as an example, this beefy motor is factory rated at 460 HP, but Ford notes that this is achieved on 91 octane fuel, based on the SAEJ1349 standard. So, running a lower octane rating in this performance focused engine will no doubt lead to lower horsepower ratings. This is not due to the gas itself but due to the Mustang's ignition system retarding spark to compensate for the lower detonation or ignition point. At the end of the day, the only thing you'll have more of at the end of the day is a few more dollars in your pocket from the money you saved by going with the cheaper 87 octane. Actual power output with lower octane fuel is a hard number to lock down but most studies show a reduction of 2% for naturally aspirated motors.
It should be noted that turbocharged motors like the SAEJ1349 standard are especially susceptible to the negative effects of lower octane fuel due to the effect of compressed air that a turbo puts on an engine.
Do You Need 93 Octane To Make The Most Power?
Technically, yes, 93 octane may produce marginally more power than lesser octane fuels but the real question here should be: Is it worth it to run 93 octane in your Mustang? Here, the differences in economy vs performance collide and the purpose of your Mustang must be brought into focus. When it comes time for naturally aspirated powertrains like the Coyote 5.0L V8, running 87 will net you less power but only a few percent less. If you don't plan to track your car and are utilizing it as a daily driver, these few extra ponies will probably never be noticed. However, if you are a particular kind of owner who's looking for the most power, or have a 91+ octane dedicated tune, go with 93 octane (or whatever is highest in your area).
If you run an EcoBoost Mustang (310 HP on 93 Octane), then the story becomes a little more murky. In 2015, Ford ran into some PR troubles by misquoting the power of the EcoBoost Mustang. Here, the EcoBoost achieved 310 HP on 93 octane, which is not available in some markets. Running 87 octane netted a huge decrease in power, all the way down to 275. Check out the story here for more information. So, if you're running an EcoBoost, it's definitely best to run the good stuff or you'll suffer some serious power losses.
87 vs 93 Octane: What's The Answer?
If you want the most power, run the good stuff!
However, you'll need to be wary that it may not always be worth it for you in every situation. If you daily drive your Mustang and only see marginal improvements in performance, that extra few cents at the pump will absolutely add up. However, if you track your car or happen to own an EcoBoost motor (remember, turbos love high compression fuel) then you should be running 91+ by default.
Additionally, if you live in the southeast and you're looking to take your Mustang or Ford to the next level with top-notch Ford service & installation work, then you're at the right place! Be sure to set up an appointment with our Valdosta, Georgia Service Center or Pompano Beach, FL Service Center for everything from dyno tuning to supercharger installations, and more!
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