Pico’s question was. Will using Gasohol cost more than using straight petrol?
To answer that would require an intensive and time-consuming survey.
I think the short answer is, yes, in the long term, using gasohol would cost more than using petrol.
I know fuel consumption will be higher, maintainance is very likely to be higher and repairs could be an issue over an extended period of time.
However, you would have taken so long to find out the actual cost difference, the bike would have aged during the survey and been so old therefore, probably sold or traded in for a newer model.
If we use the 70,000-kilometer figure you have done on your bike, you would have to travel 35,000 kilometers separately using both fuel types and also ensure the motor started each 35,000 kilometers in the same condition so that everything was equal.
Then compare the quantity of fuel consumed and purchase cost. You would have to do the 70,000 kilometer very quickly as fuel costs are always changing and it would be hard to put an average price over that period that would work fairly to both fuels.
It is a proven fact that more fuel is required to achieve the same power output when using gasohol than when using petrol.
10% alcohol is a very small amount; however, it is enough to reduce the total amount of energy produced in the combustion process.
Therefore, the EFI system will be sending more gasohol to the combustion chamber because you will hold the throttle position open slightly more to achieve the same performance output from idle to maximum revs in comparison to the EFI system using petrol.
The total cost for fuel would be very close taking into account the slightly lower purchase price of Gasohol but balanced by the higher consumption than using petrol.
Your motor will wear out no matter what fuel you use. The oil you use and how often you change it, are the biggest controlling factor in the engine doing high kilometers.
Let’s leave the components that are in contact with the fuel system but are not part of the engine moving parts, out of the total costs for now. The replacement and cost to maintain these components will be obvious and will occur long before the engine needs a rebuild. So every time you buy a part that has failed due to suspected gasohol use, you need to record the cost. You also need to be sure that the part would not have failed in the same way using petrol.
Petrol and Gasohol do impact your motor in different ways. As has been said before in these posts, fuel in Thailand can be dirty. However, we are trying to find out if using Gasohol will end up costing more than using petrol. Both types of fuel use petrol as the base fuel.
One at 100% the other at 90% so if it is dirty fuel before mixing with alcohol the dirty fuel is going to impact the motor the same way regardless of the alcohol mixture. Actually, the alcohol will assist in separating the dirt contamination from the petrol. However, it will still be in the fuel system to do its dirty work.
The only internal engine parts the fuel has a direct impact on, are the piston, cylinder and valves, valve guides.
The remainder of your motor is lubricated by the oil. The only place the fuel and oil can contaminate each other is in the cylinder bore as the oil is dragged up and down the cylinder and mixed with vaporised fuel on the cylinder wall. The fuel will contaminate the oil this way. For example when you labour your motor, it is receiving fuel but not completely burning it. The abundant unburnt fuel can and will contaminate the oil more quickly.
As your motor slowly wears out, the piston rings and valve stems/guides will seal less. When the motor is running this reduced seal will allow some of the gases to blow by and enter the crankcase and cam area (rocker cover). These gases will condensate and mix with the oil. This along with fine particles from the metal surfaces the oil lubricates is what turns nice clean oil, black.
Gasohol fuel contains alcohol. Alcohol has two negatives that will contribute more to the wearing out of the above-mentioned sections of your motor faster than petrol will.
The first is, alcohol is corrosive and the second is, alcohol absorbs water.
Alcohol is corrosive because it absorbs water and the water contains oxygen. These components go hand in hand. Think “Rustâ€