Have you ever wondered why diesel cars are priced higher than petrol? Is it because diesel engine is complex and has high weight? I guess no. As far as my guess goes its purely a pricing strategy. Diesel cars fetch more profits to manufacturers as they have compelling low maintenance logic.
Lets assume following case for petrol and diesel car.
Petrol Car:
Price : 6 lacs
Petrol Price: 55
Mileage: 12 km/ltr
Cost Per KM: 4.6 Rs
Your average daily km: 20
Diesel Car:
Price : 7 lacs
Petrol Price: 35
Mileage: 16 km/ltr
Cost Per KM: 2.2 Rs
Your average daily km: 20
Price difference: 1 lacs
To cover this price difference between diesel and petrol, you need ...
KM Per Day Years
20 5.7
40 2.8
60 1.9
100 1.14
If you lower the diesel price or lower petrol mileage, you may end up breaking even bit early. In a nut shell, go diesel if you average 40km or more. This way you will start reaping benifits of fuel savings earlier.
Now lets take case of ford fiesta vs maruti zen
Zen:
Price : 5 lacs
Petrol Price: 55
Mileage: 12 km/ltr
Cost Per KM: 4.6 Rs
Fiesta:
Price : 8 lacs
Petrol Price: 35
Mileage: 18 km/ltr
Cost Per KM: 1.94 Rs
Price difference: 3 lacs
For fiesta to catch up this price difference, it would need ..
KM Per Day Years
20 15.7
40 7.8
60 5.2
100 3.11
But you cut this time by half assuming that fiesta provides much better luxury and performance!!!