Can You Mix E85 With Regular Gasoline?

There are affiliate links on this article. If you make a purchase through any of the links, I may earn a small commission at no extra cost to you.

Powerful engines need good, high-quality fuel and oil to keep running at great efficiency. If you find out that your vehicle’s engine isn’t running as powerful as expected, one of the things to reconsider is the type of fuel you’re using in the engine.

Flex-fuel vehicles run best with E85, but E85 fuel is mostly scarce, and as such, some people blend it with regular gas to get enough quantity for their needs. But, can you mix E85 with regular gasoline? The simple answer is YES. However, there are key things you need to know about mixing fuels.

E85 and regular gasoline differ in pretty many aspects but are majorly based on the “Octane” level and “Ethanol” level. This article clearly explains what happens when you decide to mix E85 fuel with regular gas (83 – 87).

Introduction to E85 Gas

To put it in the simplest form, E85 gas is a type of fuel with 85% “Ethanol.” That is to say, the fuel is basically a blend of Ethanol and any other hydrocarbon (depending on the need).

E85 fuel is typically a blend of ethanol and regular gasoline; ethanol takes 85% concentration in the mix, while gasoline takes the remaining 15%.

Well, not all engines are built to run with fuels that have high ethanol content; hence, E85 fuel is mostly specified for flex-fuel vehicles (FFVs); non-flex fuel vehicles either use diesel, or regular gas (85 – 87), or premium gas (91 – 94).

Notwithstanding, FFVs can run with regular gasoline; yeah, FFV engines are flexible and can run with any type of gasoline or fuel blend – just don’t put diesel in the fuel tank! On the contrary, non-Flex-Fuel engines may “knock” if you put in E85.

Regular Gasoline Overview

Regular gas is what you buy in every fuel station out there; it is basically a type of fuel with octane levels from 83 – 87. If the octane level exceeds 87, it’d be considered “Premium Gas.” Theoretically, premium gas has higher octane than regular gas, but practically, both offer almost the same benefits/performance.

Higher octane only reduces the chances, and possibilities of engine knocking. It is safe to blend regular gas and E85, because, E85 already contains gasoline (though in a small quantity).

The result would be more like to even out the octane levels in the regular gas with the ethanol levels in the E85. however, some engines are built to use only premium, high octane gas (91 – 94).

Can You Mix E85 With Regular Gasoline?

Just as mixing oils is cool, mixing E85 and regular 85/87 gas is cool. The engine using the blended fuel would continue to run normally as it used to. But it is important to note that mixing different fuels won’t improve an engine’s performance – or boost the horsepower in any way.

Also, the type of car you’re going to run the fuel on is very important here; blended fuels can work smoothly in FFV engines, but if you use them in regular ICEs, you may be risking fatal engine damage, that may even warrant buying a brand new engine.

That said, when you mix E85 with regular gasoline, make sure you’re not putting it into a non-flex-fuel vehicle – you’d ruin the engine by doing so.

The engines in non-flex-fuel vehicles are not designed to withstand the high impact of ethanol; thus, feeding them with ethanol fuel would cause them to wear/corrode faster.

More so, even if not regular gas, when you mix E85 with another type of fuel, don’t run it in a regular ICE vehicle; instead, put the mixed fuel in an FFV and you’re good to go.

Related Questions

Can You Mix E85 And 87 Gas?

Yes, you can mix E85 with any other type of gasoline. E85 on its own already contains gasoline in low quantity, which implies it is compatible with regular gas. 87 gas is high on octane, E85 is high on ethanol, the blend would give you fuel with octane level around 45% and ethanol around 55%.

Can You Mix E85 And Premium Gas?

Premium gas is any gas with octane levels up to 91% or higher; yes, you can mix premium gas with E85, but it would not trigger an increase in performance of your engine – or anything of such. It’d be more beneficial for your engine if you use only premium gas or E85 alone.

Can You Mix E85 And 91?

91 gas is premium gas, and as such, you can mix it with E85 gas. However, ensure that the fuel is used in an FFV engine to avoid damage. Blended fuels aren’t good in regular ICE vehicles.

Will Regular Gasoline Ruin an E85 Engine?

Apparently, E85 engines are designed to run with either gasoline only, E85 fuel only, or a blend of both. So, using only regular or premium gas in an E85 engine is all cool and nothing is going to happen in the long run, too.


So, can you mix E85 with regular gasoline? The short answer is YES. However, before mixing the fuels, ensure you’re going to use it in an FFV engine. Only flex-fuel engines can seamlessly run with blended fuels without issues.

On the contrary, if you mix fuels in a non-FFV engine, you may be in the market a few months later for a new engine. In summary, mixing E85 with regular gasoline is doable, but the engine where the fuel will be used must be compatible with E85.

Similar Articles:

Scroll to Top