So, what happens when you purchase an excellent little car with a standard transmission, try not to accelerate too quickly, try not to rush to a light which is red anyway, don't speed (no more than 5-10 km/h above the speed limit, even on a 400-series highway), don't bother stepping on the gas if you're already on a slight gradient down, and don't use air conditioning more than once in a blue moon (though you must use it occasionally, otherwise you may have problems later)? You get better fuel economy than is even suggested by the Transport Canada Fuel Consumption Guide 2004 of 4.6 L/100 km (= 61 mpg (UK)) for highway driving and 6.2 L/100 km (= 46 mpg (UK)) for city driving. (Yes, Transport Canada still uses the imperial gallon (denoted by gallon (UK)) of 4.54609 L and not the US gallon of 3.785411784 L.)
Background
For interest, my 2004 Volkswagen Golf GL TDI was purchased at Volkswagen Waterloo. It has a sun roof (a negative so far as fuel efficiency is concerned, though I'm glad I have it) and alloy wheels (a definite positive for fuel efficiency). I do almost all of my driving in the Kitchener-Waterloo area and no more than 200 km out of 1000 km is highway driving. The combined fuel efficiency for this ratio of city-highway driving would be 5.88 L/100 km. Even if I to drive 30% of my kilometres on the highway, the combined fuel economy would still be 5.72 L/100 km.
Why Buy Diesel?
As diesel is more expensive than gasoline ($1.45/L as opposed to $1.30), this may lead one to ask: why by a diesel? As can be seen from the table below, the VW Golf is running at roughly 5.5 L/100 km, and if you assume that a person drives 25000 km/a and the cost of diesel is $1.45/L, then you would spend just under $2000/a on diesel. If you have a gasoline engine running at 7 L/100 km, this works out to $2275/a. If you are doing more highway driving, this difference will, most likely, grow.
Fuel-Efficiency Plot
I plotted this data, and it seems that, as I keep the car longer, the fuel efficiency is improving. I am not really sure how to explain this; however, factors may include the quality of diesel and my driving habits.
Figure 1. Plot of year versus fuel efficiency with a least-squares best fit of sinusoid and a straight line.
As expected, fuel consumption increases in the winter months. See the log for the actual data.
Fuel Consumption Log
Table 1 gives the dates and amounts of my fuel purchases together with the odometer and tripometer readings. Following this is a calculation of the fuel economy based on these numbers with the fuel economy presented in L/100 km, mpg (US), and mpg (UK). Of course, as the amount to which the tank is filled varies with each purchase, the fuel consumptions must therefore be approximations, however, over time, the variations will average out.
Table 1. Fuel consumption of my VW Golf GL TDI.
| Date | Odometer (km) | Tripometer (km) | Fuel (L) | Rate (¢/L) | Cost | L/100 km | mpg (US) | mpg (UK) |
|---|---|---|---|---|---|---|---|---|
| - | - | - | - | - | - | - | - | - |
| - | - | - | - | - | - | - | - | - |
| - | - | - | - | - | - | - | - | - |
| - | - | - | - | - | - | - | - | - |
| 05-01-29 | 11577 | 259.5 | 20.007 | 79.9 | 15.99 | 7.71 | 30.5 | 36.6 |
| - | 183972 | 819.?2 | - | - | - | - | - | - |
| 05-03-09 | 12795 | 398.4 | 24.008 | 82.9 | 19.90 | 6.026 | 39.0 | 46.9 |
| - | 134752 | 680.?2 | - | - | - | - | - | - |
| 05-04-27 | 14030 | 555.0 | 33.501 | 81.7 | 27.37 | 6.04 | 39.0 | 46.8 |
| 05-05-15 | 14783 | 752.8 | 42.005 | 81.7 | 34.32 | 5.580 | 41.15 | 50.6 |
| - | 156282 | 845.?2 | - | - | - | - | - | - |
| 05-06-19 | 16480 | 852.1 | 45.030 | 88.9 | 40.03 | 5.544 | 42.4 | 51.0 |
| 05-07-12 | 17320 | 840.2 | 48.001 | 88.9 | 42.67 | 5.713 | 41.2 | 49.4 |
| 05-08-06 | 18168 | 847.7 | 47.0021 | 88.9 | 41.78 | 5.545 | 42.4 | 50.9 |
| 05-08-24 | 19003 | 831.7 | 47.0021 | 92.9 | 43.66 | 5.651 | 41.6 | 50.0 |
| 05-09-01 | 19535 | 531.8 | 29.999 | 97.9 | 29.37 | 5.641 | 41.7 | 50.1 |
| 05-10-05 | 20282 | 747.2 | 40.003 | 95.9 | 38.36 | 5.353 | 43.9 | 52.8 |
| 05-10-06 | 20893 | 610.8 | 34.000 | 95.9 | 32.61 | 5.566 | 42.3 | 50.7 |
| 05-10-093 | 21719 22217 | 825.3 498.2 | 20.004 43.005 | 103.5 95.9 | 20.70 41.24 | 4.761 | 49.4 | 59.3 |
| 05-11-09 | 22957 | 740.1 | 46.010 | 92.9 | 42.74 | 5.775 | 40.7 | 48.9 |
| 05-11-25 | 23660 | 702.3 | 41.006 | 92.9 | 38.09 | 5.541 | 42.5 | 51.0 |
| 05-12-11 | 24224 | 564.0 | 37.005 | 87.9 | 32.53 | 6.561 | 35.8 | 43.1 |
| 05-12-?? | 24876 | 652.3 | ? | ? | ? | ? | ? | ? |
| 06-01-02 | 25226 | 349.9 | 42.002 | 87.9 | 36.92 | - | - | - |
| 06-01-27 | 25849 | 623.7 | 44.000 | 89.9 | 39.56 | - | - | - |
| 06-02-10 | 26488 | 639.7 | 44.003 | 88.3 | 35.32 | 6.879 | 34.2 | 41.1 |
| 06-02-25 | 26801 | 313.0 | 23.005 | 86.5 | 19.90 | 7.350 | 32.0 | 38.4 |
| 06-03-18 | 27533 | 742.9 | 46.002 | 86.5 | 39.79 | 6.192 | 38.0 | 45.62 |
| 06-04-01 | 28261 | 727.3 | 40.002 | 86.5 | 35.47 | 5.500 | 42.8 | 51.4 |
| 06-04-21 | 29095 | 834.4 | 45.003 | 95.9 | 43.16 | 5.393 | 43.6 | 52.4 |
| 06-05-02 | 29844 | 749.0 | 40.003 | 95.9 | 38.36 | 5.341 | 44.0 | 52.9 |
| 06-05-13 | 30855 | 1010.2 | 50.02 | 101.9 | 50.97 | 4.951 | 47.5 | 57.1 |
| 06-06-17 | 31766 | 911.7 | 50.026 | 99.9 | 49.98 | 5.487 | 42.9 | 51.5 |
| 06-07-13 | 32667 | 892.9 | 50.003 | 95.5 | 47.75 | 5.600 | 42.0 | 50.4 |
| 06-08-01 | 33592 | 925.5 | 49.004 | 95.5 | 46.80 | 5.295 | 44.4 | 53.3 |
| 06-08-20 06-08-27 | 34872 | 1280.0 | 21.051 43.005 | 103.9 99.9 | 21.87 42.96 | 5.004 | 47.0 | 56.5 |
| 06-08-17 | 35853 | 980.7 | 49.000 | 96.9 | 47.48 | 4.996 | 47.1 | 56.5 |
| 06-10-08 | 36189 | 334.7 | 22.005 | 85.9 | 18.90 | 6.575 | 35.8 | 43.0 |
| 06-10-27 | 37023 | 834.1 | 47.005 | 85.9 | 40.38 | 5.635 | 41.7 | 50.1 |
| 06-11-18 | 37874 | 851.3 | 49.008 | 85.9 | 42.10 | 5.757 | 40.9 | 49.1 |
| 06-12-02 | 38686 | 811.6 | 45.040 | 92.9 | 41.85 | 5.550 | 42.4 | 50.9 |
| 06-12-09 | 38962 | 275.5 | 20.026 | 85.9 | 17.20 | 7.269 | 32.4 | 38.9 |
| 06-12-23 | 39795 | 833.0 | 45.015 | 85.9 | 38.67 | 5.404 | 43.5 | 52.3 |
| 07-01-11 | 40627 | 832.0 | 47.005 | 85.9 | 40.38 | 5.650 | 41.6 | 50.0 |
| 07-01-27 | 41339 | 711.9 | 45.007 | 85.9 | 38.66 | 6.322 | 37.21 | 44.68 |
| 07-02-18 | 42067 | 729.6 | 49.017 | 85.6 | 41.96 | 6.718 | 35.01 | 42.0 |
| == | == | == | == | == | == | == | == | == |
| 07-04-07 | 43531 | 741.2 | 42.020 | 97.6 | 41.01 | 5.669 | 41.49 | 49.83 |
| 07-05-01 | 44311 | 780.0 | 45.003 | 96.9 | 43.61 | 5.770 | 40.77 | 48.96 |
| 07-05-13 | 44854 | 542.9 | 29.999 | 96.9 | 29.07 | 5.526 | 42.57 | 51.12 |
| 07-05-30 | 45600 | 745.4 | 37.999 | 92.9 | 35.30 | 5.098 | 46.14 | 55.41 |
| 07-06-04 | 46465 | 865.0 | 44.47 | 96.7 | 43.00 | 5.14 | 45.75 | 56.95 |
| 07-06-11 | 47252 | 907.0 | 40.003 | 96.9 | 38.76 | 4.410 | 53.33 | 64.05 |
| 07-06-30 | 48064 | 811.8 | 42.005 | 93.9 | 39.44 | 5.174 | 45.46 | 54.59 |
| 07-07-13 | 48814 | 749.4 | 40.003 | 93.9 | 37.56 | 5.338 | 44.06 | 52.92 |
| 07-07-21 | 49647 | 833.5 | 44.999 | 93.9 | 42.25 | 5.399 | 43.57 | 52.32 |
| 07-08-06 | 50647 | 999.5 | 50.003 | 93.9 | 46.96 | 5.003 | 47.02 | 56.46 |
| == | == | == | == | == | == | == | == | == |
| == | == | == | == | == | == | == | == | == |
| 07-10-30 | 55121 | 1071.5 | 53.2 | 93.9 | 50.00 | 4.965 | 47.37 | 56.89 |
| == | == | == | == | == | == | == | == | == |
| 07-12-15 | 56866 | 1744.3 - " | 48.004 | 103.9 | 49.88 | == | == | == |
| 07-12-26 | 57581 | 715.2 | 45.020 | 110.9 | 49.93 | 6.295 | 37.37 | 44.88 |
| == | == | == | == | == | == | == | == | == |
| 08-03-15 | 61109 | 1384.9 - " | 30.052 | 116.9 | 35.13 | == | == | == |
| 08-03-22 | 62022 | 912.7 | 47.002 | 119.9 | 56.36 | 5.150 | 45.67 | 54.85 |
| 08-03-30 | 62841 | 819.0 | 50.011 | 120.8 | 60.41 | 6.106 | 38.52 | 46.26 |
| 08-04-28 | 63775 | 934.4 | 51.002 | 125.9 | 64.21 | 5.458 | 43.09 | 51.75 |
| 08-05-23 | 64654 | 879.3 | 49.996 | 135.9 | 67.94 | 5.686 | 41.37 | 49.68 |
| 08-07-05 | 65573 | 918.9 | 50.000 | 145.9 | 72.95 | 5.441 | 43.23 | 51.92 |
| 08-07-19 | 66579 | 1005.9 | 50.022 | 144.9 | 72.48 | 4.973 | 47.30 | 56.80 |
| 08-08-03 | 67548 | 968.4 | 50.004 | 139.9 | 69.96 | 5.163 | == | == |
| == | == | == | == | == | == | == | == | == |
1 Yes, this is strictly coincidence.
2 Estimated missing data.
3 Rick's Esso on Hwy 401 charges absurd prices for diesel, so I only got enough to get me to Waterloo. In fact,
PetroCanada, unfortunately, appears to charge much more for diesel than other service stations. Pity. I'd wish
they'd stop trying to offer me a credit card.
Note on Conversion Rates
The conversion from n L/100 km to mpg (US) may be done by calculating
112903/(480×n) ≈ 235.215/n
and to mpg (UK) by calculating
56826125/(201168×n) ≈ 282.481/n.
One US gallon is 231 cubic inches (the old wine gallon), one inch is 0.254 dm, and 1 L is one cubic decimetre. One imperial gallon was originally the volume occupied by 10 lbs of water at a particular temperature and pressure, but today is simply defined as 4.54609 L.
Comparisons
The VW Golf with a gasoline engine uses approximation 50% more fuel and thus, when gasoline prices were at an all-time high, had I purchased a VW Golf with a gasoline engine, I would have still been paying approximately twice what I am paying now, and even if I had bought the most fuel efficient Ford Focus (which has significantly less room than the Golf) and used only the cheapest gasoline, I still would have ended up paying more than 80% more than at the height of the crisis. Of course, had a purchased a Mercedes-Benz Smart Car, I would be paying approximately 25% less than what I am now (as it, too, runs on diesel). C'est la vie.
For another comparison, when the gas prices were at an all-time high ($1.35/L for regular and $1.50/L for premium), people driving those large SUVs were paying at least 5× and sometimes more than 6× what I was paying to go the same distance. I really hope that the drive in those large SUVs is 6× better than mine, for their drivers' sake. If they want to pay 33¢/km, that, after all, is their right.
Of course, while the fuel consumption of this little car is wonderful, both for me and the environment, the Golf has other nice features: excellent European styling, quality workmanship (made in Brazil), and a snappy and responsive drive.
Besides, gasoline still is relatively cheap relative to flavoured sugar water: coffee, if you buy extra large, is $3.74/L, and Coca-Cola is similar in price if you purchase it in a vending machine.
Biodiesel
Consider visiting the Non-profit Fuel Cooperative.
Disclaimer
This page has been created by an independent owner of a 2004 Volkswagen Golf TDI. In no way am I affiliated or associated with Volkswagen or with any Volkswagen dealership.
