E85 Vs 93 Gas: Detailed Comparison

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For over a decade now, you must have read and heard lots of stuff about E85 gas; its flexibility, and efficiency. However, E85 fuel is yet to be globally available as regular and premium gas.

The scarcity of E85 makes drivers consider “Premium Gas” as an alternative fuel for their vehicles, and that is where the 93 gas comes in. However, between E85 and 93 gas, which is more efficient and beneficial to your car’s engine?

This E85 vs 93 gas comparison article looks into the core differences between these two types of fuels, which are considered to be “Better” than regular gas (85 or 87).

In a nutshell, E85 is flex-fuel while 93 is simply an unleaded gas with 93% octane concentration.

What is E85 Gas?

E85 gas or E85 fuel (commonly called E85 for short) is a blend of ethanol and a hydrocarbon (mainly gasoline). The “E” signifies the presence of Ethanol, while the number “85: represents the ethanol’s percentage.

In essence, E85 is a type of fuel with 85% ethanol; the remaining 15% is for the hydrocarbon used, usually gasoline.

The popularity of E85 gas increased as more flex-fuel vehicles got introduced to the market. Flex-Fuel vehicles are meant to drive with E85 fuel for more efficiency, and potentially, an increase in horsepower output. E85 is more environmentally friendly than 93 gas.

What is “93?”

When a mechanic, auto engineer, or driver says “93,” he/she isn’t referring to math numbers but a type of gasoline known as “Premium Gas.” 93 is unleaded gasoline with octane levels up to 93 percent. It is commonly seen as a better gas than “Regular Gasoline,” which has octane levels between 83 – 87.

The higher octane levels in 90 gas help to prevent gasoline engines from knocking.  It is also poised that 93 gas cleans the engine better than regular gasoline. Well, compared with E85, 93 gas has very little ethanol concentration – roughly 10%.

You can use 93 gas on any vehicle with a gasoline engine; however, it is specified for certain engines. 93 gas is the same as 91 and 92 gas; they are all in the “Premium” gas range.

E85 Vs 93 Gas: Key Differences

With the detailed overview of E85 and 93 written above, you can easily tell some differences between these two types of fuels. Notwithstanding, hereunder are the detailed differences between E85 and 93.

1. Supported Engine Type

This is one of the main differences between these two fuels; you can’t use them interchangeably in most engines. E85 is meant for engines that are flex-fuel compliant; you shouldn’t use E85 on regular ICEs, it’d damage the engine.

But, on the other hand, 93 gasoline can be used in flex-fuel compliant engines. The thing is, flex-fuel compliant engines are flexible; they can run with only gasoline or E85 fuel; also, they can run with a blend of both (E85 and unleaded gas).

So, to put it simply, you can run 93 gasoline in an E85 engine, but cannot run E85 in a gasoline engine.

2. Horsepower Output

Any driver would do anything feasible to get the highest HP output possible from his vehicle’s engine. One of the ways to achieve improved horsepower (HP) is by using the right type of fuel for your car’s engine.

E85 is poised to offer improved horsepower output, and also clean the engine better than regular gasoline. However, this does not mean that 93 premium gas does not make an engine run pretty much better than regular gas.

Just as E85 gives you the best out of an FFV (Flex Fuel Vehicle) engine, 93 premium gas gives you the best out of a typical gasoline internal combustion engine. But, horsepower gain with E85 is higher than 93 gas.

3. Fuel Economy and Efficiency

Now, here’s something that would draw you back a bit from choosing E85 fuel over gasoline. First off, E85 is less efficient (about 25 – 35% less)  than 93. Also, you won’t get decent fuel economy with E85 as you’d get with 93.

So, it’s safe to say that 93 gives saves you more on fuel usage and efficiency. The inefficiency of E85 is because of its lower burn rate – due to the high ethanol content.

4. Availability and Environmental Impact

E85 is still scarce even though it’s been around for years – you may not see E85 gas in the fuel stations in your locale. But of course, 93 gas is available everywhere, including in tier 1 fuel stations.

Talking of environmental impact, E85 is more environmentally friendly than 93 gasoline. E85 produces fewer carbon footprints and emissions than gasoline. As a renewable fuel, E85 is more eco-friendly.

5. Price

Typically, E85 is cheaper in fuel stations where it is available. 93 is the most expensive gas you can buy; it is about 30% more expensive than E85.

E85 Gas Vs 93 Gas: Which is Good For You?

This depends on the type of engine you’ve got; an FFV engine can run with only gasoline, and can also run with E85 – however, E85 would make it perform better. On the contrary, 93 is best for ICE vehicles that are built to run with gas, only.

It’d be much better to get 93, which is premium gas, than getting 87, which is regular gas. The higher octane in 93 helps to protect the engine against situations such as “Knocking.” Notwithstanding, if you’re in for cheaper and eco-friendly fuel, E85 is the answer.

Note: If your engine is not E85 compliant, using E85 fuel in the engine would cause irreparable damage. If your car is non-FFV, you must work on the engine to be E85 compliant before running flex-fuel in the vehicle.


Conclusively, E85 vs 93 is all about price, availability, and efficiency. 93 is available in virtually all fuel stations and it is more efficient too. On the other hand, E85 is more environmentally friendly and cheaper to afford.

Choosing between these two fuels, there are many things to consider, which include the availability of either of them in your locale, your car engine type, environmental consequences, and more.

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