Ethanol & Flex Fuel Tuning: Mixing Ethanol Blends
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Mixing Ethanol Blends
05.21
| 00:00 | - While pump E85 is a viable option for many around the world, the variability of the ethanol content that we've already covered is an obvious concern for those who want to push the performance boundaries with their engine. |
| 00:12 | Of course there are also many cities and countries where pump E85 isn't available. |
| 00:18 | This gives you the option to buy commercially available E85 from a race fuel manufacturer, which we'll cover in the next module, or to mix your own E85. |
| 00:28 | Mixing your own E85 or any blend of ethanol for that matter is quite a viable option, and can work out a little cheaper than commercial fuels. |
| 00:38 | Provided you're patient and have a high level of attention to detail, you can also produce a finished blend of fuel that is very consistent. |
| 00:47 | You can of course also choose to use a high octane gasoline to mix with your ethanol, rather than whatever a pump E85 manufacturer may use. |
| 00:56 | In order to mix your own ethanol blends, you'll need to begin with a source of pure ethanol or E100 as it's often referred to. |
| 01:05 | In reality we'll actually be using what's referred to as denatured ethanol, which is often used commercially as a cleaning product, or as a base for perfumes and aerosols. |
| 01:16 | Denatured means that the pure ethanol has been mixed already with a hydrocarbon based product to make it unsuitable for human consumption, and therefore make it exempt from alcohol beverage taxation. |
| 01:28 | You can purchase drums of E100 from bulk chemical suppliers in most countries without difficulty, although in some regions this may require a permit depending on your local laws. |
| 01:40 | It's important to know that storing bulk flammable liquids like this is normally not covered by residential or commercial insurance policies due to the higher risk of fire, so you're best to confirm this with your insurer first. |
| 01:55 | Next you're going to need to source the gasoline that you want to use to mix the ethanol to your desired blend. |
| 02:01 | It would be typical here to select the highest octane pump gasoline that you have access to. |
| 02:06 | However the reality is that the knock resistance of ethanol is so high that the octane of the gasoline component is less critical than many would think. |
| 02:16 | You need to base your decision here on what the fuel is going to be used for. |
| 02:21 | If it's for a mildly modified engine running a little more boost than stock, then you're likely to be absolutely fine using a low octane pump fuel for your blending. |
| 02:31 | If on the other hand you're really pushing the limits and running exceptionally high boost on a high compression engine, then you'll want all of the knock resistance you can get, and it's sensible to use a high octane gasoline for your blend. |
| 02:45 | Once you have your base components, you're then able to mix the fuel to your required ethanol content. |
| 02:51 | This needs to be done by volume. |
| 02:53 | And you need to be very accurate with your measurements. |
| 02:57 | Probably the most common technique would be to mix the fuel and pour it into a 20 litre fuel container which is a little easier to transport and fill your car from. |
| 03:06 | I use a five litre clear plastic measuring jug with graduated measurements on the side that makes it very easy to accurately add a specific volume of the fuels. |
| 03:17 | These can be sourced reasonably cheaply from the likes of eBay. |
| 03:21 | Deciding what proportion of the fuels to add is quite simple. |
| 03:25 | Once you decide on the final ethanol content, you want to calculate how this equates to the required volume of each fuel. |
| 03:33 | Let's say for example that we want to mix 20 litres of E85. |
| 03:38 | This means that 85% of the total fuel volume will be ethanol, and 15% will be gasoline. |
| 03:45 | We can turn these percentages into a volume by multiplying our total fuel volume by the individual percentages. |
| 03:53 | For example 85% can also be expressed as 0.85 If we multiply this by 20 we get a result of 17 which means that 20 litres of E85 will contain 17 litres of pure ethanol. |
| 04:10 | By definition this obviously means the remaining three litres is gasoline, but you can calculate that just as easily by taking 0.15, which is 15%, and multiplying this by 20, which equals three. |
| 04:25 | Once we know what volume of the fuels we want, we can use the mixing jug to measure them out and add them to whatever container we're going to be storing our fuel in. |
| 04:35 | One of the advantages of mixing your own fuel, is that you can choose any blend of ethanol you want. |
| 04:41 | As we'll find out a little further into the course, we tend to see the biggest improvement in knock resistance occur as we move from E0, or pure pump gasoline, through to around E40, an ethanol content of 40%. |
| 04:55 | As we move from E40 through to E100, the knock resistance does increase, but those increases are smaller. |
| 05:03 | For this reason a lot of people tend to use blends around 35% to 40% ethanol, which provides a large improvement in knock resistance without impacting on the fuel system requirements as much as you would see with a blend such as E85. |
