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E85 instead of racing fuel
- Thread starter Tinkerer
- Start date
appsyscons
New member
Gasoline is a saturated hydrocarbon, with a fixed amount of energy, in each gallon.
91 octane gasoline has an energy density of 44.8MJ/kg per gallon
Ethanol has an energy density of 31.68MJ/kg per gallon
energy density = amount of energy stored (available) in a given volume or given mass
MJ = megajoule
kg = kilogram
BTU= brutish thermal unit (unit of energy)
So 1 gallon of 91 octane, 'pure' gasoline is 125,000BTU
and 1 gallon of ethanol is is rated at 129 octane, contains 84,600 BTUs per gallon
Ethanol is an octane booster, and does not contain the same amount of energy as gasoline.
85% Ethanol + 15% 91gasoline, resulting an 123.3 octane rating blend, if you do the math, contains around 91,500BTUs per gallon. NOTE: they most likely will use a lower grade of gasoline in the blend, since the octane is boosted by the ethanol.
Bottom line, to do the work of 1 gallon of 'real' gas, you need to burn 1.36 gallons of gas/ethanol blend.
In other words, 36% more gas/ethanol blend to go as far.
I bet you the 'tree huggers' didn't share this info with you. Not as "green" as advertised!
To answer you question, higher C/R just extracts more of the available energy from the fuel. Also remember that they can use much lower octane gas in the E85 blend, the stuff chemically closer to the heptane molecule than to the octane molecule, so your actual octane, in E-85 might be much lower, and closer to 91.
91 octane gasoline has an energy density of 44.8MJ/kg per gallon
Ethanol has an energy density of 31.68MJ/kg per gallon
energy density = amount of energy stored (available) in a given volume or given mass
MJ = megajoule
kg = kilogram
BTU= brutish thermal unit (unit of energy)
So 1 gallon of 91 octane, 'pure' gasoline is 125,000BTU
and 1 gallon of ethanol is is rated at 129 octane, contains 84,600 BTUs per gallon
Ethanol is an octane booster, and does not contain the same amount of energy as gasoline.
85% Ethanol + 15% 91gasoline, resulting an 123.3 octane rating blend, if you do the math, contains around 91,500BTUs per gallon. NOTE: they most likely will use a lower grade of gasoline in the blend, since the octane is boosted by the ethanol.
Bottom line, to do the work of 1 gallon of 'real' gas, you need to burn 1.36 gallons of gas/ethanol blend.
In other words, 36% more gas/ethanol blend to go as far.
I bet you the 'tree huggers' didn't share this info with you. Not as "green" as advertised!
To answer you question, higher C/R just extracts more of the available energy from the fuel. Also remember that they can use much lower octane gas in the E85 blend, the stuff chemically closer to the heptane molecule than to the octane molecule, so your actual octane, in E-85 might be much lower, and closer to 91.
WETTE VETTE
New member
Are they using E85 from the pump or from a drum? I have considered this but ultimately chose not to because I hear the mass produced E85 available from the pump is very inconsistent in terms of octane and alcohol content. Plus depending on who you talk to E85 from the pump has an actane anywhere from 100 - 108. This octane level would be great for an 11 or 12:1 motor, but nothing above that in my opinion. A well designed motor with the proper combustion chamber treatment and a tight .040-.045" quench can run premium with 10.5:1 (aluminum head). The added power from 1 point of compression and a little from the alcohol in E85 would be nice, but not worth the additional $$ to properly set up the motor to run on this in my opinion.
I've heard (not first hand experience) that E85 from the pump can vary enough to require tuning adjustments regularly with each fillup unless the motor is running EFI with the ability to self adjust. Until someone else proves otherwise I'm staying clear.
Coolerman
Charter Member
I don't think E85 would have a long of shelf life, which is not good if it sits in your boat for a month.
Also, will E85 be tougher on fuel system parts? Your fuel tanks being the biggest factor here?
A good cheap race fuel that is widely available is 100ll av gas. Its actual octane on an automotive scale is around 104-105. It's around $4 a gallon. From an aviation standpoint, it has a low lead content, but from an automotive standpoint, it actually has a high lead content (similar amount to C16 race fuel) so this will be good for your valves. Also, 100ll avgas won't be hard on your fuel system, and 100ll is also very consistent as the FAA isn't fond of planes falling out of the sky.
Also, will E85 be tougher on fuel system parts? Your fuel tanks being the biggest factor here?
A good cheap race fuel that is widely available is 100ll av gas. Its actual octane on an automotive scale is around 104-105. It's around $4 a gallon. From an aviation standpoint, it has a low lead content, but from an automotive standpoint, it actually has a high lead content (similar amount to C16 race fuel) so this will be good for your valves. Also, 100ll avgas won't be hard on your fuel system, and 100ll is also very consistent as the FAA isn't fond of planes falling out of the sky.
Coolerman
Charter Member
As far as the octane rating goes, I have generally heard that E85 has an octane rating of 104-108.
Another thing to think about, since you have to run more fuel, your intake temps will go down, resulting in more hp. Might be a nice setup for a street car that has some boost and no intercooler.
Another thing to think about, since you have to run more fuel, your intake temps will go down, resulting in more hp. Might be a nice setup for a street car that has some boost and no intercooler.
Ratickle
Founding Member / Super Moderator
NMMA, others challenge E15 ruling
National Marine Manufacturers Association
March 26, 2013
Filed under News
On March 25, 2013 the National Marine Manufacturers Association (NMMA) as a part of The Engine Products Group, comprising the Alliance of Automobile Manufacturers (Alliance), The Association of Global Automakers, the Outdoor Power Equipment Institute and the National Marine Manufacturers Association; filed a petition for certiorari asking the U.S. Supreme Court to review the DC Circuit Court of Appeals’ August 2012 decision that none of the trade associations or parties had standing in the case. The group is challenging the Environmental Protection Agency’s (EPA) decision to grant partial waivers approving the sale of gasoline containing 15 percent ethanol (E-15) for 2001 model year and newer passenger cars and light trucks. The Court of Appeals dismissed the case for lack of jurisdiction in August 2012.
The petition asks the Supreme Court to accept the case for review. If the Supreme Court accepts the case, the parties will then ask that court to reverse the Court of Appeal’s ruling and find the parties have the right to challenge EPA’s partial waiver decisions that allow sale of E15 for some passenger cars and light trucks but not older vehicles and not for use in motorcycles, boats and off road engines.
NMMA has long been fighting on behalf of the recreational boating industry as it relates to the dangers to consumers of using fuel with a percentage of ethanol above 10 percent in boat engines and the detriment it causes to the $72 billion per year U.S. recreational boating industry.
National Marine Manufacturers Association
March 26, 2013
Filed under News
On March 25, 2013 the National Marine Manufacturers Association (NMMA) as a part of The Engine Products Group, comprising the Alliance of Automobile Manufacturers (Alliance), The Association of Global Automakers, the Outdoor Power Equipment Institute and the National Marine Manufacturers Association; filed a petition for certiorari asking the U.S. Supreme Court to review the DC Circuit Court of Appeals’ August 2012 decision that none of the trade associations or parties had standing in the case. The group is challenging the Environmental Protection Agency’s (EPA) decision to grant partial waivers approving the sale of gasoline containing 15 percent ethanol (E-15) for 2001 model year and newer passenger cars and light trucks. The Court of Appeals dismissed the case for lack of jurisdiction in August 2012.
The petition asks the Supreme Court to accept the case for review. If the Supreme Court accepts the case, the parties will then ask that court to reverse the Court of Appeal’s ruling and find the parties have the right to challenge EPA’s partial waiver decisions that allow sale of E15 for some passenger cars and light trucks but not older vehicles and not for use in motorcycles, boats and off road engines.
NMMA has long been fighting on behalf of the recreational boating industry as it relates to the dangers to consumers of using fuel with a percentage of ethanol above 10 percent in boat engines and the detriment it causes to the $72 billion per year U.S. recreational boating industry.
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