Someone advised to add small amount of 2T oil in petrol for smoother engine,more power and mileage. So me and a friend tried it today as an experiment. We filled the tank of Maruti Ritz with Normal unleaded petrol and drove from Chandigarh to Patiala ( about 80Kms ) Spent couple of hours with friends there. On way back topped up the fuel tank again and added 80ml of Castrol 2T oil. The engine felt definitely smoother, both at low and high speed , can't say about power. Haven't calculated the milege yet, will update soon. Regularly mixing 2T might clog the system but I'd definitely recommend trying it once on a long trip. Note: 2T oil should not be more than 1ml per Litre of Petrol.