Found this interesting...
Quote:
E15, a mixture of 15% ethanol and 85% gasoline, may eventually be sold in the United States. Currently E10 (10% ethanol) is a choice or the only choice at the gas pumps in many states. How could a switch to E15 potentially impact old cars?
I decided the place to start my research was the “Flex Fuel” vehicles that can run on E85, 85% ethanol. They have been on the road for more than a decade. About half of new GM vehicles can run on E85. How is a Flex Fuel vehicle different than my 1979 Chrysler or a newer, non-E85 capable vehicle?
The simple but perhaps best answer is that from the beginning Flex Fuel vehicles were designed to run on 85% ethanol. Ethanol critics point out that ethanol is more corrosive to some materials than gasoline. It has only about 67% of the energy density of gasoline but higher oxygen content. More oxygen, higher octane, means a leaner mixture and potentially hotter combustion and exhaust temperatures. Ethanol is more likely to absorb water, which might lead to problems like corrosion and a gummy varnish.
None of these characteristics of ethanol mean that it is good or bad compared to 100% gasoline. It is just a different fuel and engines need to be designed to run on it. And cars have been designed to run on ethanol for over 100 years. Some Model Ts were built for ethanol fuel. Modern racecars often run on 100% alcohol. Cars in Brazil have been running on various alcohol concentrations for 30+ years.
Since at least the 1990s, car manufacturers in North America have been thinking about ethanol when they designed engine fuel systems. If a part could possibly work on both Flex Fuel vehicles and non-Flex Fuel vehicles, then they would just use the one part rather than spending money to design two. Owners of late model vehicles usually do not have to worry that the fuel injector o-rings, fuel pumps, fuel tanks, etc. will be corroded by ethanol. Those parts are likely the same parts used on the Flex-Fuel, 85% ethanol vehicles. Much of what is unique about Flex Fuel vehicles is in the sensors and software. The engines need to be able to know if they are receiving 87 octane gasoline or 100+ octane alcohol and adjust the timing, idle speed, etc. accordingly.
Flex Fuel vehicles might have some unique parts (fuel filters, oxygen sensors, etc.) compared to non-flex fuel models built the same year. For example, early Flex Fuel Fords have a Flex Fuel Sensor that detects the amount of ethanol in the fuel mixture. That Flex Fuel Sensor by Airtex/Wells currently costs more than $600 at RockAuto. But unique, expensive sensors and other parts are likely to continue to fade away as Flex Fuel increasingly becomes the norm.
So E15 probably will not dissolve the fuel systems in late model cars and maybe their engine computers, knock sensors and other parts can recognize and correctly respond to higher octane E15, but what about my 1979 Chrysler? There the news is not good because there really is no clear news. I was excited when I saw a US government sponsored report on the impact of E15 on “legacy” vehicles. That is until I discovered that legacy only meant 10 years old! The study only indicated they were reasonably confident that E15 would not have a negative impact on 2001 and newer, legacy vehicles.
There have been studies of off road engines found in lawn mowers, marine engines, snowmobiles, etc. that could relate to old cars. Air-cooled weed whackers and old cars with carburetors do not have oxygen sensors that provide the engine with feedback on the correctness of the fuel mixture. There are concerns that ethanol could create too lean a mixture and too much heat. Ethanol might dissolve rubber components or the composite body of my Chrysler’s Carter four-barrel carburetor. There are just too many different old engines and engines not designed for ethanol for anyone to make any 100% guarantees about the impact of E15, E20 or higher ethanol concentrations.
Increasing ethanol concentrations in five percent increments appears to be nothing but a “let’s see what happens” gamble for truly old cars. With all the old cars and other engines not designed for ethanol out there, hopefully 100% gasoline or at least E10 will remain available. Now I better understand why E15 is such a political, environmental, technical and legal hot potato.
Tom Taylor,
RockAuto.com
Quote:
E15, a mixture of 15% ethanol and 85% gasoline, may eventually be sold in the United States. Currently E10 (10% ethanol) is a choice or the only choice at the gas pumps in many states. How could a switch to E15 potentially impact old cars?
I decided the place to start my research was the “Flex Fuel” vehicles that can run on E85, 85% ethanol. They have been on the road for more than a decade. About half of new GM vehicles can run on E85. How is a Flex Fuel vehicle different than my 1979 Chrysler or a newer, non-E85 capable vehicle?
The simple but perhaps best answer is that from the beginning Flex Fuel vehicles were designed to run on 85% ethanol. Ethanol critics point out that ethanol is more corrosive to some materials than gasoline. It has only about 67% of the energy density of gasoline but higher oxygen content. More oxygen, higher octane, means a leaner mixture and potentially hotter combustion and exhaust temperatures. Ethanol is more likely to absorb water, which might lead to problems like corrosion and a gummy varnish.
None of these characteristics of ethanol mean that it is good or bad compared to 100% gasoline. It is just a different fuel and engines need to be designed to run on it. And cars have been designed to run on ethanol for over 100 years. Some Model Ts were built for ethanol fuel. Modern racecars often run on 100% alcohol. Cars in Brazil have been running on various alcohol concentrations for 30+ years.
Since at least the 1990s, car manufacturers in North America have been thinking about ethanol when they designed engine fuel systems. If a part could possibly work on both Flex Fuel vehicles and non-Flex Fuel vehicles, then they would just use the one part rather than spending money to design two. Owners of late model vehicles usually do not have to worry that the fuel injector o-rings, fuel pumps, fuel tanks, etc. will be corroded by ethanol. Those parts are likely the same parts used on the Flex-Fuel, 85% ethanol vehicles. Much of what is unique about Flex Fuel vehicles is in the sensors and software. The engines need to be able to know if they are receiving 87 octane gasoline or 100+ octane alcohol and adjust the timing, idle speed, etc. accordingly.
Flex Fuel vehicles might have some unique parts (fuel filters, oxygen sensors, etc.) compared to non-flex fuel models built the same year. For example, early Flex Fuel Fords have a Flex Fuel Sensor that detects the amount of ethanol in the fuel mixture. That Flex Fuel Sensor by Airtex/Wells currently costs more than $600 at RockAuto. But unique, expensive sensors and other parts are likely to continue to fade away as Flex Fuel increasingly becomes the norm.
So E15 probably will not dissolve the fuel systems in late model cars and maybe their engine computers, knock sensors and other parts can recognize and correctly respond to higher octane E15, but what about my 1979 Chrysler? There the news is not good because there really is no clear news. I was excited when I saw a US government sponsored report on the impact of E15 on “legacy” vehicles. That is until I discovered that legacy only meant 10 years old! The study only indicated they were reasonably confident that E15 would not have a negative impact on 2001 and newer, legacy vehicles.
There have been studies of off road engines found in lawn mowers, marine engines, snowmobiles, etc. that could relate to old cars. Air-cooled weed whackers and old cars with carburetors do not have oxygen sensors that provide the engine with feedback on the correctness of the fuel mixture. There are concerns that ethanol could create too lean a mixture and too much heat. Ethanol might dissolve rubber components or the composite body of my Chrysler’s Carter four-barrel carburetor. There are just too many different old engines and engines not designed for ethanol for anyone to make any 100% guarantees about the impact of E15, E20 or higher ethanol concentrations.
Increasing ethanol concentrations in five percent increments appears to be nothing but a “let’s see what happens” gamble for truly old cars. With all the old cars and other engines not designed for ethanol out there, hopefully 100% gasoline or at least E10 will remain available. Now I better understand why E15 is such a political, environmental, technical and legal hot potato.
Tom Taylor,
RockAuto.com
