Tata Nano runs on a 624cc MPFi (Multi Point Fuel Injection) petrol motor, which develops a maximum power output of 37bhp with 51Nm. The car returns the class leading mileage of 25.4kmpl. Nano's power might seem minimal over the paper but its 600kg weight works here, which returns an effective power to weight ratio.
New Tata Nano with EasyShift is available at Rs. 2 lac (Ex-showroom, Delhi), and the final cost depends on the valuation of your car. So, first get the valuation of your car from authorized Tata dealer, so he can give you a final quote for the new car.