I Might Just Know What I'm Talking About
Join Date: May 2002
Location: Selma,CA in the middle of the vineyards, Central California
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OT- Outboard Motor News,
Thought some of you fellas might be interest in this:
Specially the phasing out of Small & Large block GM motors.
Welcome to the Winter 2007 issue of OUTBOARD NEWS, an electronic newsletter for the outboard enthusiast.
Not much has changed from last year in terms of outboard motor technology. Horsepower has reached a plateau of 300 HP, and prices are exceeding $20,000. Sales volume is about 350,000 units. If divided equally among all the manufacturers, that would be 50,000 units each. Not a big number.
A little off-topic, but still interesting, are the changes coming to stern drive and inboard engines. The small block and big block GM V-8 and companion V-6, which have been around for 40 years, are planned to become obsolete and will no longer be manufactured for use in cars and trucks. That means relatively cheap horsepower coming in the form of high-volume automotive production will be a thing of the past. The exception may be one or two models like the three liter in-line four cylinder. These are used in cars and made south of the border.
State and Federal regulators will require catalytic converters to be sandwiched into the exhaust system downstream from the exhaust manifold. These catalytic converters will be cooled and wrapped with insulation, because they take up space in the engine compartment and raise ambient temperatures.
One alternative to catalytic converters might be direct fuel injection (DFI), which has been shown to significantly reduce carbon monoxide in the exhaust. This technology has the potential to eliminate the need for catalytic converters. Several foreign car manufacturers are already using DFI on their gasoline engines, as are the two-stroke outboard builders. Putting the fuel in the cylinder only after the ports or both intake and exhaust valves are closed is the way of the future for reciprocating internal combustion engines.
Ethanol as a fuel is becoming ever more popular, and there has been much uncertainty over its effect on marine engines. We will begin some questions and answers on the subject, with the information provided by Mercury Marine.
1. What are ethanol and ethanol-blended fuels?
Ethanol for fuel is highly refined beverage(grain) alcohol, approximately 200 proof, that can be produced from natural products such as corn, sugar cane and wheat. New technology will allow ethanol to be made from "cellulosic" feedstocks including corn stalks, grain straw, paper, pulp, wood chips, municipal waste, switchgrass and other sources. Ethanol used for fuel has been "denatured" or rendered unsafe to drink by the addition of a hydrocarbon (usually gasoline). The ethanol-blended fuel E-10 refers to fuel that contains 10 percent ethanol and 90 percent gasoline. Similarly, E-85 contains 85 percent ethanol and 15 percent gasoline. E-85 is intended only for engines specially designed to accept high-ethanol content fuel blends, such as the Flexible Fuel Vehicles (FFV) made by some car companies.
2. How is ethanol made?
In the US, ethanol is typically produced by removing the starch or sugar portion of corn and fermenting it. The fermented starch is then distilled into alcohol. Excess water is removed, resulting in very pure-200 proof- ethyl alcohol (ethanol).
3. What are the characteristics of ethanol?
Ethanol is an oxygenated hydrocarbon compound that has a high octane rating and therefore is useful in increasing the octane level of unleaded gasoline. The EPA has allowed the use of ethanol in gasoline at levels up to 10 percent as an octane enhancer and to provide beneficial clean-burning combustion characteristics that help improve some emissions.
Ethanol is hygroscopic (it has an attraction for water) and will more readily mix with water than with gasoline. It has different solvency behaviors than does gasoline, which allows it to loosen rust and debris that may lie undisturbed in fuel systems. And it can more readily remove plasticizers and resins from certain plastic materials that might not be affected by gasoline alone. Loose debris will plug filters and can interfere with engine operation. Additionally, ethanol is corrosive to some metals, especially in combination with water. Although gasoline does not conduct electricity well, ethanol has an appreciable capability to conduct electricity and therefore can promote galvanic corrosion.
4. Does ethanol affect horsepower or fuel efficiency?
Ethanol has a heating value of 76,000 BTU per gallon, which is approximately 30 percent less than gasoline. The result is E-10 gasoline which should yield slightly lower mileage- a decrease of about 3 percent. Fuels containing higher levels of ethanol will have a corresponding reduction in mileage. For example, E-85 fuels produce mileage about 30 percent less than gasoline. The octane rating of pure ethanol (200 proof) is about 100 and is therefore useful in elevating the octane value of gasoline. In E-10 blends the presence of ethanol provides about 2.5 to 3 percent of the overall octane rating. The effect on engine horsepower is determined by the octane result of the blended fuel. Care should be taken to select fuels having the octane rating recommended for the engine as indicated in the owner's manual for proper operation.