QUOTE(kslee79 @ Jul 17 2014, 09:57 AM)
NOOB question here. Does Euro 4 > Euro 3 > Euro 2 in terms that they are better for the engine, or is it just better for the environment (emission standards), or BOTH? If Euro 2 is still pure and clean (good for engine) but just that it cannot meet more stringent emission standards, then it's really no big deal to the main concern of this thread (I know, environmentalist would disagree but let's just leave that to another topic)!
yes, euro rating covers many things but mainly focuses on emissions, the higher the euro grade the less emissions it produces.
while emissions are good for enviroment, what does it mean for your engine?
take one category that euro grading focuses on : sulphur content.
sulphur in the fuel when combusted produces sulphur dioxide. Sulphur dioxide when mixed with water produces sulphuric acid. This acid is what we call 'acid rain' in environmental terms. Now this sulphur dioxide also mixes with the water in your engine, water that comes from the air and as by product of combustion. Because no engine is 100% sealed in the combustion chamber this acid eventually gets into your engine oil and starts degrading it. Since you cant see or feel its effects you normally dont care about it, but it's there and it's eating away at stuff inside your engine
so. Euro 3-4 fuels are good for any engine, not just for the enviroment