E85 viability as a road fuel and a race fuel

Ethanol, mixed with unleaded fuel at an 85/15 ratio (respectively), is E85 fuel.  In the early 2000's, flexible fuel vehicles began rolling off of the assembly line from Ford Motor Co. and Chrysler Motors LLC.  GM followed suit closely behind, and E85 was on its way to being a viable fuel source.  These new vehicles tout electronic fuel injection systems that work in somewhat differing fashions to allow any ethanol blend from E10 (standard pump fuel from 2001 on, 10% ethanol, 90% unleaded gasoline) to E85, and maintain a reasonable stoich air fuel ratio.  For gasoline, perfect combustion occurs at 14.3:1 air to fuel ratio as measured by an oxygen sensor in the exhaust.  For E85, perfect combustion occurs at ~9.6:1 air to fuel ratio.  (race on E85, par 1)  The electronic fuel injection systems in these cars are able to "tweak" the fuel injector dwell rate (the time the injector is open relative to crankshaft rotation) to add the additional fuel needed for the ethanol combustion.  Ford and Chrysler use a set of four oxygen sensors to accomplish these adjustments, and GM uses oxygen sensors as well as an inline ethanol content tester in the fuel line, allowing the GM cars to adjust more quickly to the E10-E85 mixture, and more precisely meter the fuel into the engine.  Add to that the amazing increase in E85 pumps springing up around the country, and the fuel becomes even more of a viable fuel source.

(http://www.e85fuel.com/e85-and-ethanol-blends/)

You'll notice above I said that injectors must be open longer to run higher levels of ethanol.  This is one of the drawbacks to running E85.  The fuel usage for an apples to apples vehicle, one running E10 (standard pump unleaded) and another running E85 will be greater by approximately 30% for the E85 vehicle.  What this means is the entire fuel system has to be able to flow at least 30% more in comparison to the E10 counterparts.  This does translate into an approximately 30% decrease in fuel economy while using E85, the main argument against utilizing E85 in everyday vehicles.  Although E85 is cheaper by the gallon (~$2.15-$2.50/gallon in Denver metro), the additional fuel required does not make Ethanol a cheaper alternative to gasoline unless gasoline soars to above $4.00/gallon with no change in E85 pricing.  The reason for this is that a gallon of ethanol contains approx. 80,000 BTUs. A gallon of unleaded regular contains about 119,000 BTUs.  The lower amount of potential energy effects the overall fuel economy.  (Ethanol par 4)

So if you look purely at BTU's, one might come to the conclusion that E85 would make less power than gasoline.  On paper it may look this way, but we are comparing a gallon to a gallon.  Once you add the additional fuel supply required for E85, the benefits start to shine in a high performance application.  In fact, the Indianapolis Racing League (IRL) has switched all Indy cars to 100% ethanol for these extremely high performance machines.  (http://www.ethanol.org/index.php?id=50 E85) has been given an octane rating of 105, although with its lower combustion chamber temperatures, it is as resistant to pre-ignition and detonation as 110 octane leaded racing fuel (~$7.50-$9.00/gallon).  Because of these facts, and the fact that ethanol itself is a bio-fuel, capable of being produced, refined, and utilized all in this country, as well as the relative ease of finding the fuel, I chose to use E85 this year in my racecar, a 1970 firebird with a 468 cubic inch big block Chevrolet with Brodix heads and a converted 1150 cubic feet per minute holley "dominator" carburetor that I had converted by Mark Sullens E85 Carburetors out of Kansas City, MO.  (Mark Sullens E85, par 1)

Photo Courtesy of Steve Wolf

Mark Sullens did an awesome job on my carburetor.  When the unit is sent to him, he gave me a form to fill out to ensure my carburetor would be set up perfectly for my application. I couldn't be happier with the conversion that I paid for. 

Throughout the year, I spent time learning the new fuel as well as a new car, new fuel pump, and new ignition.  I chased a few problems for the first month or so, but once I got some fine tuning completed, and a wideband oxygen sensor, I got the car figured out.  The air to fuel ratios have been perfect, and when I wasn't having to tune the car at the track, I started winning some races, and finished 25th in points in Pro ET at Bandimere Speedway in Morrison, CO, and 12th in points in PRO ET at Douglas Motorsports Park, Douglas, WY, and earned a spot at the ET division finals in Topeka, KS.

For my "scholarly" journal, I chose to use an article posted in SAE international based on a direct injection/port fuel injection flex fuel setup used in the Ford Motor Company's "ecoboost" engines.  This setup uses a port fuel injected engine for E10 fuels, just like the "normal" port fuel injected engines of modern day, but the differences start there.  The "ecoboost" engine uses a direct injection setup for e85, that is, the E85 blend is injected into the combustion chamber much like many newer diesel engines, as opposed to the port injection it uses for the e10 blend that injects the fuel on top of the intake valve.  By utilizing this dual setup, the "ecoboost" engine was able to bridge the fuel economy gap between e10 and e85, bringing the economy within 10%, yet the engine was able to produce almost 50% more horsepower by direct injecting the e85 blend, and adjusting the fuel and spark curves to best burn the available ethanol in the combustion chamber. 
This new technology, and the new usage of multiple injection systems for different blends of fuels, in my opinion, is absolutely the future of ethanol blended fuels. (Stein, House, and Leone par 2).
Next time... Biodiesel

http://www.raceone85.com/
http://www.e85fuel.com/e85-and-ethanol-blends/
http://marksullense85carburetors.com/
http://www.ethanol.org/index.php?id=50
http://saefuel.saejournals.org/content/2/1/670.abstract