Fuel-it ethanol content tester


Oct 14, 2019
2017 Bmw M2
In this thread I will be reviewing the Fuel-it ethanol content tester. Before we begin I have to extend a shout out to Fuel-it for giving me a discount/reimbursement to review this tester, but like always I will be writing an unbiased review.

All images in this review were taken by me.


Any technical advice, installation instruction, or product installation, product usage tips, any form of advice provided in this review, or decision to purchase a product is done so at your own risk I will not be responsible for personal injuries, injuries to others or any living being, any damage to your car, or any property damage.


First lets talk about shipping, since I know it may be scary to have a small glass test tube be sent in the mail - since these things can be fragile. Well for this fuel tester they wrapped it in bubble wrap and shipped it within a fedex cardboard envelope that also has bubble wrap in its interior. So the fuel tester was fairly well protected and arrived to me without issue. Shipping was also pretty fast taking about a week to get to me, and processing time took about a day which is also really fast.


In this section we will be looking over a few critical areas of fuel testers and how fuel-it improved on their tester to make it surpass all other fuel testers on the market, and addressed any potential issues.

Importance of using an ethanol tester:

With the growing popularity of OTS tunes that utilize ethanol blends like BM3 and MHD, the need to know the exact content of ethanol you use to blend becomes ever so important. This is because if you use too much ethanol your fuel trims will go too far out of range which can cause tuning issues and your HPFP can even crash. If you do not have enough ethanol due to your E85 station dispensing low concentrations of ethanol, your octane ratings can be lower than required by your tune causing knock and potentially engine failure. So it is really important to know the percentage of ethanol that your E85 station is dispensing so an affordable tool like this is extremely important.

Cap Material/construction:

This is an extremely important aspect of ethanol fuel testers because they must be shaken to mix the ethanol and water. So if a cap is made of unsuitable materials it can cause a leak and that will cause the percentage reading to be off (literally every drop counts) and cause a mess.

Standard ethanol testers:
- Utilize a cheap plastic cap either with no seal or a silicone based rubber seal.
- This brings in potential issues because if a seal is not used the coarse thread design of the cap and the design utilizing very few threads can result in a leak.

- If a cheap rubber or silicone seal is used the gasoline and ethanol in the e85 can make the seal swell also resulting in a leak.

- This is what generally occurs with cheap ethanol content testers on the market.

Fuel-it ethanol tester:

- Fuel-it used to use a cheap plastic cap like what was described above and reports did have it leaking. But like what is the norm with fuel-it they listen to customer reports and strive to improve their products. So they introduced a second generation of cap which is a thin tin cap with a foam like gasket. This is similar to what a vodka bottle cap would be like and the design is completely immune to the seal swelling effects from alcohol or gasoline, and thus this cap does not leak over time like cheaper caps do.

- I have tested this cap with both E88 and pure 91 octane gasoline both left in the fuel tester for a few days (upside down so the fuel would contact the cap and the foam seal) and there was no seal swelling and no leaking of any sort after that duration. So I am extremely impressed and happy with the cap design of the fuel-it tester.


Credit: F87source


Credit: F87source



Credit: F87source

The next thing to note with the fuel-it ethanol content tester is the markings on the tube itself. Unlike other cheaper testers which have inked on markings, the fuel-it ethanol content tester is laser etched into the glass test tube. This means that the fuel-it tester will not be susceptible to the markings fading over time due to the solvent nature of ethanol and gasoline (which is really good at dissolving ink markings like those found on cheaper testers).


Credit: F87source



So above is an image of a lab/medical grade BD syringe which is one of the most high quality syringes you can buy, unlike those cheap dollar store/amazon syringes. This is what I use to suck some ethanol out of my fuel jug to add into the ethanol tester, and as you can see just with a few exposures to e85 the markings on the side of the syringe has been washed off. This is what will eventually happen to cheaper ethanol content testers with simple printed on markings the ethanol will dissolve those markings and it will eventually fade (ethanol will also dissolve permanent marker so essentially it doesn’t matter what ink you use it will all fade), making these cheaper testers a paper weight. So imo the most important thing in an ethanol content tester is the markings, because if those fade the tester is useless - therefore this laser etching alone makes fuel-it’s tester the best on the market as no one else is doing it.

The next notable feature of the fuel-it ethanol content tester is the marking intervals. Unlike other cheaper testers which have marking intervals ever 5% or 10% in terms of ethanol content, and only covers from E50 - E85 or sometimes even less than that range. The fuel-it ethanol tester has an interval every 2.5% and goesl from E0 - E100. This is such a nice thing to have because you are able to measure nearly every single possibility of ethanol concentration you would like, for eg. E10 or E15 etc. You can also measure ethanol concentrations of E88 or E87.5 which is impossible on those other cheaper testers. This range of measurement is critical because not every gas station will provide exactly E85, there is often a large variation and the concentration will depend on the last digit which is often not a 0 or a 5 meaning those cheaper analyzers will not be able to give an accurate reading. This is another reason why the fuel-it ethanol tester is superior to the competition.

The markings are also crisp, sharp (not a huge blob of a line), and easy to read which is nice when you must look at the bottom of the meniscus.

Flat bottom/build/volume/Warranty:

The fuel-it ethanol tester also has a nice flat bottom to the tester which allows you to stand the tube upright on your truck lid while adding in the E85 allowing you to focus on adding the precise amount and not have to focus on holding the tube.

The build quality of the ethanol tester is also made of glass, this is extremely nice because it allows for a long usage life because glass is chemically inert and will not be damaged and made brittle by gasoline or ethanol.

The fuel-it ethanol tester in its small size option is about 15 mL in volume, this means that you will not have to waste a ton of E85 filling up this tube and there will also not be alot of waste liquid to dispose of.

This fuel tester also comes with a lifetime warranty against defects or fading, so if you ever encounter any issues you can have it replaced! This just shows their confidence in this product lasting, compared to those other cheaper testers out there.

Quick Summary on how to use the fuel tester and how it works:


Credit: F87source

First add water to the tester, add the water until the bottom of the meniscus is at the water fill mark as denoted by the red arrow in the image above.

Then add E85 to the tester until the meniscus is at the fuel line, as denoted by the orange arrow in the image above.

Then cap the fuel tester and shake it until the water and E85 is mixed, the solution will be cloudy so you will have to let it sit for a bit until the solution is clear.

Since the ethanol in the E85 is soluble in water and the gasoline is not, the two will separate. The ethanol will be dissolved in the water or aqueous phase which sits below the gasoline phase due to water’s higher density.

So the more ethanol present in the ethanol the higher the separation line will be meaning a higher ethanol reading. Simple!

After the solution has settled read the ethanol concentration by looking at the separation line at eye level and looking at the bottom of the meniscus. As shown in my photo by the black arrow my E85 concentration is slightly below the E87.5 line and so it is around E87. So this is some really high quality E85 at my local station - which is known to have high E85 concentration year round even in the winter!


Overall the fuel-it ethanol content tester really is the best on the market, it has a great construction, a refined cap design that doesn’t leak, nice sharp easy to read markings with a great interval range, and a lifetime warranty. So if you are looking for an ethanol tester this is the one to have.
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