So why is E85 the fuel of the future?

Some of the things that we are questioned frequently is what are the real advantages to E85?  How do I tune for E85?  Can I go back to gasoline?  What do I need to convert?

In this article I am going to explain the benefits and problems with E85. One thing that E85 allows us to do is run racegas levels of boost and timing without having to pay the price of racegas. E85 is of course 85% ethanol and 15% gasoline. This can vary based on the blender of the fuel and the company that is ordering. As a result the rated octane at the pump is listed at 105. The interesting thing about this is this is not the normal rating system we are used to, such as 92 or 93 octane.

Those numbers are found by using the R+M/2 method. The R stands for Research octane which is the maximum rating that a fuel was found to be. The M is Motor octane which is the minimum that a given fuel will be.

To understand this more fully follow this link:

http://en.wikipedia.org/wiki/Octane_rating

Another interesting read on the exact octane of E85 can be found here:

http://forums.evolutionm.net/alternative-fuel/385257-octane-rating-e-70-...

Notice posts 7 & 8 in particular.

 E85 on a stock Evo VIII or IX can allow you to run upwards of 34-35psi and generally make 400whp+ (on a stock turbo) depending on the level of modifications. We have experimented in other vehicles as well and to try to see the limits of what is possible. Our customer and good friend, Jeff Bush, runs E85-E98 in his racecar and has made 820whp at 37psi and run as much as 47psi at the track.

 E85 burns cooler and cleaner, leaves no soot on the bumper, and is generally inexpensive and always less than the equivalent race fuel would be. It is unleaded fuel so it wont contaminate catalytic converters or O2 sensors like leaded race fuels. It will actually also offer evaporitive cooling similar to methonal injection, though not quite as effective.

Some things to keep in mind if you are building an engine and want to build it specifically for E85 is it does like a little higher compression (10:1) than a gasoline motor. If you are going to remain dual fuel, then no more than 9.5:1 is what we typically recommend though we have run 10:1 motors on 92 octane and 22psi.

Now for the drawbacks (but there is a silver lining):

 It can be hard to start when the temp drops below 40*F, but being users of E85 this is something that is a priority for us at EnglishRacing. We are constantly looking for starting solutions on the stock ECU. Another problem is the increased fuel consumption, which is about the 30% more that E85 needs to maintain the same level of AFR's. I personally average about 19-20 on the highway on E85 and 25-26mpg on 92. What does it take?

To convert to E85 from gasoline there are a few things that you will need to do make the switch. One is of course an upgraded fuel pump and the Walbro 255lph works really well. 1000cc injectors on the stock turbo are about the minimum, and larger turbos require even more injector. Generally we rate the overall whp goal relative to the amount of injector and fuel pump.

For instance:

460whp is about the limit of 1000s and a single 255

480whp is about the limit of 1200s and a single 255

Above this point a second pump starts to become needed. There are a few options on the market and some of them are intank and then there are inline pump options. The main reason we suggest an inline is the intank designs require an additional fuel filter because they delete it in the intank setups. This is another thing to think about is that the E85 is not corrosive but it will loosen up the deposits in the tank and potentially clog the filter. It is a good idea to replace the filter after running the E85 for awhile anyway, but of course another option is to add another filter somewhere in the system.

520whp or so is the limit of 1200s and dual pumps.

 If you are running on the Stock ECU in the case of the Evo (or DSMlink for the 1G/2G) the largest injectors you can still run gasoline are around the 1450 level. These are new from FIC and havent been widely publicized but they will flow enough fuel to push the car to the mid 500s. Above this 1600s become needed and there is very little way to make the car run on pumpgas on the stock ECU.

On the cars with DSMlink you might be able to push it a little but it still doesnt seem to work too well. On paper the 1450s and dual pumps should support around 750hp to the crank. Testing will show :) As you have seen E85 is not a perfect fuel, but it is very hard to beat.