When you use fuel below recommended octane level the fuel doesn't burn properly/at the right time it ignites immediately making the engine temp really hot. A good sign of lean mixture is those orangi rusty exhausts pipes we see in Pakistan. Which makes us really happy...engine tate hai
Anyway so when the temp gets really hot, 1kr-fe will start drinking it/pure evaporation. If a new car is drinking oil this means the oil is having a hard time to keep things cool. A high octane fuel actually burns slower (I know it's hard to believe) but that?s a fact
It burns slower and exactly where it has to giving you great low end and high end torque and because it doesn't ignite at wrong places it keeps temp low and the engine works at optimum level. But, unfortunately our hi octane is 92 Ron only.
To make things worst passo, vitz, belta are not designed/calibrated for our country. These cars are euro 4, 5 and 2014/15 model are euro 6 compliant. Our fuel is not even euro 1 compliant (I can be wrong, Inviting you to check ) how can you expect these cat converts to not choke. So our fuel needs an upgrade too. Most of us out there are driving on half choked cat converters I bet my life on it(Anyone who has a 1kr fe for more than a year in Pakistan). This against add to heat factor in engine.
To conclude 0w 20 is awesome plus it's recommended but with our fuel. you?ll always be topping it up every second week. I suggest 5w 30 or liqui Moly synthoil 5w 40 With genuine oil and denso air filter plus clean O2 sensor, map sensor every 10 to K.