Converting your Mustang to E85 will give you the extra boost in HP & TQ that you have been looking for. In this article, we will touch on some key factors when debating making the switch from pump gas to E85.
IMPORTANT: Late Model Restoration HIGHLY recommend that you consult with your custom tuning company before converting to E-85 fuel. Some professional tuners will have slightly different opinions on what supporting modifications are needed for an E85 conversion on your Mustang. Since they are doing the tuning, always listen to their advice. The parts listed below are a road map to show you the basic steps needed to help you do this conversion.
E85 has been a popular option among Mustang enthusiasts since it was first introduced. You can make more power for a lower price than regular pump gasoline, and it’s available at many gas stations nationwide. E85 is composed of 85% ethanol and 15% gasoline. E85 has a higher octane rating than standard 93 premium gasoline, allowing you to run more timing and boost over premium gasoline. E85 does have a few disadvantages as well. For example, E85 is unavailable at all gas stations and can be corrosive to a factory fuel system. It does have a higher octane rating; however, it does burn faster than gasoline, so it will not be quite as efficient in gas mileage.
When converting your 79-04 mustang over to E85, there are a few things to remember. Depending on your application, fuel lines, and fuel pump, you will need to upgrade your fuel injectors. When upgrading the fuel pump, you will want to ensure that the pump is compatible with E85. Using a standard pump with E85 can cause premature pump failure. Aeromotive and Deatsch Werks both have great options when it comes to E85-compatible fuel pumps.
Another major factor when converting over to E85 will be the fuel lines. The stock fuel lines do a great job of fueling many different applications and power levels. However, E-85 fuel is corrosive to the rubber fuel hoses and will quickly cause fuel line failure. It is strongly recommended that you upgrade to complete stainless lines and fuel hoses to withstand the additional flow needed when running E85 and its corrosive properties. A larger diameter supply and return line is highly recommended due to the added fuel required at wide-open throttle.
Once you have upgraded everything, the last thing to remember is a custom tune. This will be required to run everything correctly and take advantage of the higher octane fuel. A boosted application will allow you to run more boost safely. Using E85 on a naturally aspirated application will allow you to run more timing than you usually would with standard 93 gasoline.
Consider a few essential things if you want to do an E-85 conversion on your 5.0L Coyote Mustang. We will cover the specific requirements below. The great news is that it doesn’t require a lot of reworking your fuel system to an E85 conversion on your 2011+ Mustang, as these cars came with a powerful fuel pump and lines that support the E-85 fuel.
When converting your 11-14 Coyote mustang over to E-85, you need to do a few fuel system modifications for everything to run properly. Depending on your modifications, you will be required to run a minimum of a 47lb fuel injector. You will also be required to have a custom tune to support the E-85 and its needed fuel delivery. The factory fuel lines and fuel pump will support E-85 in a naturally aspirated application without issue.
Converting your 2015-17 Coyote over to E-85 does not require as many modifications depending on the vehicle. 15-17 owners can run E-85 on the factory fuel injectors as long as they run the factory intake manifold. You will still need a custom tune to calibrate the PCM for the needed fuel. However, if you own a 15-17 mustang GT with an upgraded intake manifold, you will require a minimum of a 47lb injector. The factory injectors will not be able to withstand the fueling needs from the increased airflow of the upgraded intake manifold.
The 2018+ Mustangs brought about the new Gen 3 Coyote motor, and a new direct-injection fuel delivery system came with this revision. Just like the 15-17 Mustangs, if you are running just E-85 fuel and simple bolt-on aftermarket parts such as a cold air intake and full exhaust, you will need a custom tune to support the E-85 fuel. When you start to move into more advanced performance modifications such as aftermarket intake manifolds with the combination of other aftermarket bolt-on performance parts, you will need to upgrade to 47 lb injectors. As stated above, consult your custom tuning company before making any performance modifications and running E-85 fuel to ensure they can properly set up your tune and Mustang.
|E85 FUEL ONLY||BOLT-ON + E85||BOLT-ON + MANIFOLD + E85||BOOST/NITROUS + E85|
|2011-14 MUSTANG 5.0||47 lb Injectors + Custom Tune||47 lb Injectors + Custom Tune||47 lb Injectors + Custom Tune||Consult Your Tuner|
|2015-17 MUSTANG 5.0||Custom Tune||Custom Tune||47 lb Injectors + Custom Tune||Consult Your Tuner|
|2018-21 MUSTANG 5.0||Custom Tune||Custom Tune||47 lb Injectors + Custom Tune||Consult Your Tuner|
E-85 is an ethanol-based fuel that contains 51%-83% ethanol and is readily available at many local gas stations around the country. The main benefit of E-85 is its increased octane rating. The octane of E-85 will vary depending on the actual ethanol content of the fuel. However, most E-85 will carry an octane rating of 100+. This means you can run more timing and boost, which means more horsepower. E-85 is usually found at a cheaper cost than standard premium fuel. The availability and cost of E-85 make it a great option when looking to get more power out of your Mustang. However, this fuel does come with its drawbacks. E-85 burns much faster than regular premium gasoline and will require 30% more fuel than standard premium fuel.
Yes and no, Ford Mustangs can and will run on E-85 fuel; however, they will not run E-85 fuel without some modifications. Depending on the year and model you own, it will require different modifications. We will cover the basics above to show you what is needed to run your Mustang on E-85.
The cost will vary depending on the year and model Mustang you own but also the level of aftermarket performance modifications you are currently running. For example, If you just want to run E-85 and a cold air intake on your 2011-2014 Mustang, you will need not only need a custom tune but will also need to purchase a set of 47 lb injectors; however, an E85 conversion on an S550 Mustang will not require you to upgrade your injectors if you are only running a cold air intake and E-85 fuel.
As we mentioned above, if you want to convert your 1979-2010 Mustang to E-85 fuel, you should invest in a complete fuel system for the custom tuning and any other supporting modifications you need.
Yes, E-85 fuel can add horsepower to your Mustang; however, this horsepower is not seen only because of the fuel. The fuel is simply the catalyst that allows your custom tuner to crank up the timing to maximize every cubic inch of your Mustang. When coupled with nitrous or boost, you can further add horsepower from all of the benefits we spoke about earlier. There are plenty of dyno videos out there showing that just adding E85 fuel and uploading an E85 tune to your ECU will net you more rear-wheel horsepower.
No, at this time (mid-2022), the Ford Mustang is not Flex-Fuel compatible off the showroom floor of the dealerships. As you saw above in this tech guide, you can convert your Mustang to run on E85 fuel with the help of custom tuning and aftermarket performance parts. Who knows what the future may hold. You very well could see a Flex-Fuel Mustang GT in the future, but for now, we will just need to depend on the aftermarket industry to help with this conversion.
According to most sources, E-85 has an octane rating of about 100 to 105. Most of us have 91-93 octane fuels at our local pumps. This means E-85 is going to be roughly 10 points higher in octane compared to your typical Super Unleaded fuels you will find. Its slightly cheaper price compared to most Super/Premier fuels makes this a great solution for performance enthusiasts.
There are some benefits to running E-85 fuel in your Ford Mustang. One of the most popular benefits is that it contains a higher octane level that allows you to make more RWHP (rear wheel horsepower) when combined with aftermarket performance parts and custom tuning. Mustangs running power adders such as turbo kits or a Whipple supercharger can see even further performance gains from custom tuning and E-85 fuel. The same can also be said about higher compression ratios in N/A Mustangs. The higher octane levels seen in the E85 fuel can allow for more horsepower.
Studies have shown that in many cases, E-85 fuel is cleaner burning and leaves fewer carbon deposits. This can be very beneficial with Gen 3 direct injection Mustangs, as carbon build-up is a common issue with most direct injection applications. Other studies have also shown that E-85 can absorb roughly twice the heat during combustion compared to normal gasoline. That efficiency and cooling can also help in a slight improvement in power.
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