dwsAuto Diesel Decider tool: Answers to Frequently Asked Questions

The CarToq member community has found the Diesel Decider tool very useful. That’s great!

Some members have said that the values used in the tool (car price, mileage etc) are not really applicable in their case. Others have pointed out that their loan terms and requirements might be different. Check out the Diesel Decider tool if you haven’t done so already!

A few common questions answered below:

Prashant Mohanty, Vinayak Nair, Deepak Sharma point out that actual mileage is lower than what the Diesel Decider assumes

That indeed is true.

The real world mileage is usually lower than claimed numbers. You can go and change the mileage numbers. Delete the existing number, and type in your actual mileage value.

The Diesel Decider will now give the answer based on your numbers!

Just remember to change mileage values for both diesel and petrol options. Otherwise, the result you get will be based on actual mileage for one car (the one you changed) and the claimed mileage for the other car (the one you did not change).

And when you put the actual mileage values for both the cars, most of the times the results will still be the same.

For instance, the claimed mileage for Swift diesel and petrol is 21kmpl and 18kmpl respectively, a ratio of 1.16. The actual mileage for diesel and petrol versions is somewhere around 17kmpl and 14kmpl, a ratio of 1.21. So the difference is miniscule.

The Diesel Decider uses the claimed mileage for calculations because:

• As you can see above, actual and claimed mileage both give similar results (Remember, both values should either be claimed, or both should be actual).
• Actual mileage is highly contentious figure that depends on driving skills and conditions, quality of fuel etc

Dhiraj Patra commented that his purchase price and mileage are different from the Diesel Decider values for his car

The price in the database is ex-showroom price in Delhi. Actual price would vary city by city and of course, depends on your ability to negotiate. Again, as long as you put actual prices for both cars, the result would still come out to be the same. Delete the value in the Price box, and input your actual values to get answers that are specific to your purchase price.

Amardeep Kang found the tool very basic since it does not capture the maintenance cost.

The total cost of ownership is another tool that will be made available soon.

In deciding between diesel and petrol options, however, the maintenance cost numbers are not significant enough to change the results.

Take this example: If you assume that your car runs for about 1,500 km a month for five years, you’ll end up with usage of 90,000 km. Assuming service interval to be 10,000 km, with first 3 services being free, you are likely to get your car serviced about 6-8 times. Assuming you spend Rs 5,000 per service visit
(if it’s a small car), you will spend about Rs 30,000 – Rs 40,000. For diesel version the service costs, at best, would be higher by 20%, that is a maximum of Rs 8,000 over 5 years. Or Rs 133 a month. Not a game changer!

What if the loan amount/interest rates/repayment period are different from assumptions in the Diesel Decider?

Click on Advanced Diesel Decider at the bottom of the results box to input your values for loan amount, interest rate and loan period. For instance, you might even be buying the car on down payment. In that case, just input Rs 0 in the Loan amount field. The tool will tell you how long it will take to recover the addition money paid for the more expensive diesel variant.

For instance, if you were to compare Maruti Swift VDI (Rs 5,56,227) vs Swift VXI (Rs 4,77,831), you will find that it will take you about 2 years and 5 months for fuel savings (assuming 1,000 KM/month usage) to recover the additional Rs 78,396 you will pay for the diesel model.

Similarly, you can change the interest rate, loan repayment period and the amount of loan.

If you have any other questions or suggestions for the Diesel Decider, share your comments!