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Ethanol Blending - Tips and Tricks

Posted by Dave Veal on



As you may know, EQT offers a wide variety of ethanol blended tunes ranging from E30 to E85.

Stage 1 and 2 are offered in an E30 and E85  variant allowing power and torque gains beyond that of conventional pump gas (91 and 93 Octane)

Included below are in house dyno graphs showing the gains across the various different stages as well as the clear advantage E30 can provide
VW Golf R & Audi S3

VW GTI/GLI & Audi A3

Custom tunes are available above E30 to provide greater gains when used in conjunction with larger than stock turbo's.

We're often asked for advice on how to blend fuel to achieve E30, E40 and sometimes even E85. To safely achieve these blends accurately you're going to need some equipment which will be outlined below. Safety Notice: Wear the appropriate PPE when handling fuel, always store in a safe environment away from heat and other potential sources of combustion. EQT is in no way liable for any damages that may occur. 


In order to create ethanol blended fuel, and do so safely, you're going to need to purchase some equipment

  • - Ethanol Content Tester (Required)
  • - Safe Fuel Storage Container (Required)
  • - Ethanol Content Calculator (Required)
  • - Ethanol Content Analyzer (High suggested)

Ethanol Content Tester

Ethanol Content Testers come in a variety of shapes and sizes and are sold at different price points. In this example I'm going to talk about a kit that I have experience with, 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.

Many ethanol pumps have a warning label that advises the customer of the content range at that pump, I have seen "53% - 64%" warning labels on ethanol pumps which is a main reason why ethanol content testers are required. You can't accurate calculate your mixture without knowing the content of the fuel you're using. While a lot of "pump" ethanol often reads at E70, you can't count on that to be true every time.

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 Calculator

Now that you have a known content of your Ethanol, and your gasoline (often E10) from your Content Tester, and you have it stored safely in an approved safe container. It's time to start doing a little math.

Fortunately, this is absolutely free and there are plenty of calculators on the web. For the sake of this example we're going to be using the Wallace Racing Calculator

Depending on the desired mixture you're looking to achieve, E30, E40, etc., and the amount of fuel you're looking to make your values will differ. But worry not, an example will be provided below.

We'll return to this example later to explain further.

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. However they are often required to verify 100% that the fuel being delivered to your HPFP or MPI System is actually what it needs to be. This system acts as a double check incase at any point your calculations or mix were off.

An Ethanol Content Analyzer is REQUIRED for EQT Custom E85 Tunes and is Highly recommended for any Ethanol blend tune. To learn more about what EQT Tunes require, or suggest Content Analyzers visit our other FAQ Document "Recommended / Require Modification List"

*An analyzer also allows you to future proof your vehicle for when Flex Fuel Tuning is available. 

Fuel-It Bluetooth Flex-Fuel Analyzer

Fuel-It Offers a Bluetooth Ethanol Content Analyzer with a variety of options to chose from. This kit is ideal for those who don't want to add a gauge to the already cramped VW / Audi dash boards and just want to check the content on their cell phone. 

The Fuel-It App is compatible with both Android OS and Apple iOS so whichever device you have, you're covered.

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 Flex Fuel Tunes.

However 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 VW / Audi application.
Depending on how intricate your fuel system is you may opt for a -6AN 3/8" EFI Adapter as seen here or if you have a more simplistic system an EFI Barb Adapter may be the better choice. 


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

Available at 

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, however its simply been private labeled for Innovate as indicated by the logo on the sensor

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.

Best Practices - Tips and Tricks

Now that we have all the equipment needed to accurately blend our fuel, as well as verify it once it's blended. Lets go into some best practices for blending your fuel.

VW / Audi Fuel gauges are notoriously inaccurate, making it difficult to determine how much fuel you need to mix / make.
Common MQB Fuel Capacities Noted Below:

2015 - 2020 GTI / A3 Fuel Capacity: 13.2 US Gallons
2015 - 2020 Golf R / S3 Fuel Capacity: 14.5(AWD) US Gallons
*FWD A3's will have a 13.2 Gallon Fuel Capacity, consult your owners manual.

The best way to go about mixing fuel is to run your vehicle as low as you feel safe, note that it's not uncommon to have 2-2.5 gallons left in the tank when the fuel light comes on. 

I like to use nice round numbers when blending fuel, typically 10 gallons. I will run the vehicle until the fuel light first comes on, and then proceed to fuel 10 gallons.

Here we revisit our Wallace Racing Calculator

Luckily, certain fuel blends are very easy to achieve with minimal math. A great example of this is E40.

Usually Pump Ethanol hovers around 70% Ethanol, and Pump gas is 10% Ethanol (US ONLY). It just so works out that a 50/50 mixture of these two yields E40 as demonstrated on the Wallace Calculator below. Note that the octane numbers aren't relevant just the percentage


To make E30, you'll want to reference the math above as seen in the "Ethanol Content Calculator" Section.

For those who tuned for E85, you may find that Pump Ethanol quality is insufficient and you may need to purchase sealed containers of high quality ethanol from VP Racing Fuels, Ignite Racing Fuel, or other such fuel providers. You may also want to consult your Tuner / Calibrator as often times E70 is sufficient to achieve desired results safely.


Hopefully now that you've read through this guide you have a better understanding of how to mix your fuel, what tools and equipment you'll need to do so, and some tips and tricks to do it safely.

As always, if you have any questions feel free to email us ( or reach out on Social Media by clicking the links in the footer of the page

Thanks for reading!
- Dave At EQT.
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