1. Introduction
    2. Equipment Used
    3. Ethanol Fuel: A preface.
    4. Ethanol Blending: The Lengthy method.
    5. Ethanol Blending: The Quick method.
    6. Ethanol Blending: The Dirty Method.
    7. After the Blend: The important details.
    8. Appendix


In this article, we’ll be covering our Staged E30 and Staged E85 tunes as well as custom tuning options involving ethanol fueling.

Stage 1 and 2 tunes are offered in E30 and E85 variants on most if not all platforms we support and provide the best knock resistance for peak power and drivability. We’re often asked for advice on blending Ethanol fuel with Pump 91 or 93 octane fuel, so this article seeks to cover these often-answered questions.

NOTE: Have an E85 staged tune? Fill at your local ethanol filling station, and flash to your E85 staged tune, then proceed directly to After the blend: The important details

Safety Notice: Wear the appropriate PPE when handling fuel, always store in a safe environment away from heat and other potential sources of combustion. Equilibrium Tuning INC. bares no responsibility for improperly handled fuels or damages resulting from accidents involving fuel.

Equipment Used

To create ethanol blended fuel safely, you're going to need to purchase some equipment. There are numerous types and styles of hardware kits available for testing and monitoring ethanol concentrations. We have only elected to provide a few examples in the appendix of this document, as not all customers will prefer the same hardware. Note that at a minimum you should purchase a content tester as an inexpensive option but be mindful of needing to dump the fuel safely after you’ve tested it.

Ethanol Fuel: A preface.

Ethanol fuel is an alternative fuel, primarily made from the starch in corn grain in the United States. In other regions around the world, Ethanol fuel can also be produced from sugar cane, sorghum, barley, and even beets as well as cellulosic feedstocks (wood chips, crop residues).

Ethanol contains less energy per gallon than gasoline, to varying degrees, depending on the volume percentage of ethanol in the blend. Denatured ethanol (98% ethanol) contains about 30% less energy than gasoline per gallon. Ethanol’s impact on fuel economy is dependent on the ethanol content in the fuel and whether an engine is optimized to run on gasoline or ethanol.

What does it all mean? In a nutshell, Ethanol contains up to 30% less energy, so the demand for fuel volume increases. When demand for fuel volume increases, fuel economy decreases.

Lastly, Federal Law requires that the MINIMUM ethanol percentage at any flex fuel pump (not E15, not E30), be 51% ethanol by concentration. The mandated MAXIMUM is 83% ethanol concentration. This wide range of ethanol content at the pump is the sole reason for needing an analyzer or tester.

Ethanol Blending: The lengthy method.

The first step is to locate a fueling station where you can obtain consistent ethanol fuel. As ethanol gains traction around the world, more and more fueling stations are offering this clean burning alternative fuel. We recommend a newer store that didn’t potentially drain a diesel fuel tank and repurpose it for ethanol. If you’re unsure, just ask your clerks inside and they should be able to provide you with the tank filling dates and tank cleaning dates.

With a pumping location selected, it’s time to bust out the tester (if you don’t have an analyzer) and see what that pump E85 is really testing at. Follow the directions from your tester and wait an appropriate amount of time before taking note of the ethanol content percentage.

Once you have the ethanol percentage at the pump, you can begin calculating the blend of 91 or 93 octane fuel and the pump ethanol fuel blend to achieve the desired ethanol content percentage.

NOTE: Mix ONLY the HIGHEST pump octane available to you when blending. Do not use the pre-blended E30 if available at your pump. Fueling stations will blend the lowest possible grade of fuel with E85 to provide pre-blended fuels. This means that if your station offers an E30 blend, they’re going to blend with 87 or 88 (whatever is lowest in your region) with E85. While the Ethanol mixture will still be E30, the actual octane rating can be as low as 93 octane. If you were to use 93 to blend yourself, you’d have ~97.5 octane fuel.  Using 91 would still net 96 octane E30 blend.

Ethanol Blending: The quick method.

E85 calculators take most of the guesswork out of blending. Most are free and do well enough to get you within a point or two of your desired blend, but you’ll still need to test the fueling station you’re planning to frequent.

As an example, the E85 Calc I use shown below is free, and is pretty straight-forward. We just talked about using the highest available octane for blending, and these screenshots will drive the point home (pay close attention to the octane readout below "Gas Required")


Spot the difference? 

Ethanol Blending: The dirty method.

Want E30, know what your gas tank size is, and already know what your ethanol content is at your favorite pump? These ratios will get you there:


Pump Ethanol %

Gallons of 91/93

Gallons of Pump E

Ethanol Mixture

































After the blend: The important details.

So, you’ve successfully blended the appropriate mixture to achieve E30 (or filled with pump E85 if you’re on an E85 staged tune), now what? If you’re not already on the E30/E85 tune, you can safely flash it to the vehicle, but you need to give the 91/93 fuel time to be burned off before doing any sort of aggressive driving.
We typically recommend at least 5-10 minutes of casual driving before the ethanol mixture comes up to the appropriate level in the fuel system. If you have an ethanol content analyzer installed, you can watch your ethanol content live while the fuel is passing through the sensor body. Feel free to give it the sauce once your ethanol content is at the recommended range.

We sincerely hope that this document provides you with the answers to questions we often see surrounding ethanol fueling! As always, if there are any questions or concerns please don’t hesitate to reach out to us at support@eqtuning.com or sales@eqtuning.com.



Ethanol Content Tester

Ethanol Content Testers come in a variety of shapes and sizes and are sold at different price points. Note that there are many options out there and it's up to you to purchase whichever works best for you. Fuel-It! offers an inexpensive, accurate test tube style kit at a low price which is an integral tool in blending fuel accurately as Ethanol quality varies based on pump to pump, day to day, etc. Regardless of your selection, follow the directions provided by the manufacturer of your particular test kit. 

Ethanol content calculators

There are many ethanol calculators available for free, and some are paid. We have never used paid calculators so cannot attest to the ease of use, but the guiding principles are the same regardless of the app you choose. As discussed above in Ethanol Blending: The quick method, you still need to test the ethanol concentration at your filling station if it’s not already known. Some of our favorites in no order:

E85 Calculator on Apple App Store

RaceTools on Apple App Store

E85Cal by Mike Joe on Google Play

Ethanol Blend Calculator E85 on Google Play


Safe Fuel Storage Containers

While transporting and mixing your fuel you're going to want an approved and safe fuel storage container to prevent spills and leaks. While you may be able to use the generic "red" fuel can, it's not suggested for motorsport use and there are much better options on the market.

Enter the VP Racing Fuel Can, these fuel cans are rated for alcohol fuels as well as race gas and come in a variety of colors to help you easily identify the fuel inside. Yellow for Ethanol, White for Gasoline, Green for Diesel, etc. Often you can find these fuel containers on Amazon in a 4 pack for a good price. If your fuel cans are all the same color, worry not. A simple piece of tape with a written label can save you the cost of buying multiple color fuel cans. The filler neck, venting system and large bore mouth make these ideal for motorsports use and for testing / blending your fuel to the desired content.


Ethanol Content Analyzers

While the previous item's we needed were fairly inexpensive, content analyzers are quite a bit more expensive, typically in the $200 and up range depending on how extreme you want to go with your set up.

Fuel-It Bluetooth Flex-Fuel Analyzer

Fuel-It Offers a Bluetooth Ethanol Content Analyzer with a variety of options to choose from. This kit is ideal for those who don't want to add a gauge to check the content on their cell phone. 

The Fuel-It App is compatible with both Android and Apple mobile devices.

This kit allows you to select which Sensor you use, and depending on how you plan your installation different sensors have their own set of pro's and con's.

NOTE: To aid in future proofing, under "Choose Analyzer Type" you're going to want to select "Bluetooth and 0.5 volt analog signal for JB4 or analog gauge" as this 0-5V data is going to be required for future integration with flex fuel tuning. For the sake of this example we're going to focus on the 13577429 Sensor.


This particular 13577429 sensor doesn't require any mounting holes or brackets to be used like the Continental Uni, and is the easiest to install in a VWAG application.
Depending on how intricate your fuel system is you may opt for -6AN 3/8" EFI Adapters on either end of the sensor which allow the use of higher fuel volume and cleaner engine bays. An example of said fitting is shown below:





Innovate Motorsports MTX-D: Ethanol Content % and Fuel Temperature

For those looking for an all-in-one gauge that can be tucked away in a glove box, cubby or mounted securely in a gauge pod, the Innovate MTX-D is a great option. The Innovate unit uses the same 13577429 sensor many others use, just white labeled for their branding:

The Innovate Kit also has an Analog Output wire which carries a 0-5V signal for use with Flex Fuel Capable ECU's / Tuning Platforms. We also carry the MTX-D if you prefer a gauge to be mounted somewhere. You can purchase the gauge with or without the sensor here.