If you haven't seen this thread, 50 mpg per tank at between 59-62 mph (1900-2000 rpm with DSG) is achievable. It will take light throttle, likely no a/c, high tire pressure, maybe oversize tires, and virtually no stop and go traffic, but it can be done. It certainly will take a lot of patience and perserverance (both which I don't have) to achieve 50 mpg tank after tank.
But those are unrealistic of real world scenarios, I know he did that to standardize the "test" but for us normal folk we drive cars that aren't "heated up to optimal temps", go over grades hit traffic etc.
- Allowed my car to reach operating temperature (usually took about 7 miles @ 45 MPH for the temp gauge to reach 190*F). Even though the temp gauge showed 190*F, the oil temperature probably was still below operating temperature so I didn't start recording data for about another 5 miles or so.
- Find stretches of highway of at least 3 miles that are fairly flat and where I could maintain a constant speed. This is fairly easy for me in the Valley of the Sun but I still checked my topo maps since I found a slight gain or decrease in elevation can significantly alter the data (eg. 50 feet/mile change can increase or decrease MPG by about 5 -10 MPG depending on speed).
- Set cruise control at speed to be tested via GPS and zero out the MFD1 data to begin the test.
- Record at least MPH and Average MPG from the MFD1 at the end of the run.
It really helps to have another person in the car to record the data as the data can change quickly as one changes speed.
- Repeat the test over the same route in the opposite direction. If the MPG difference between this run and the previous run was not within about 12 MPG, I didn't use the data. Either elevation change, DPF regen, or strong winds probably affecthed the data.
- Average of the results at each tested speed. After accumulating data from about 10+ two way runs (ie, both directions), I did a simple average of the data. When I compared all two way runs, the data at a specific speed was within a 2 MPG bandwidth of the average. For example, if the simple average MPG was 50, the high two way pair was less than 52 and the low two way pair was greater than 48.
Therefore 50 average is incredibly unlikely esp on a DSG equipped car.
The average MPG for a 2011 spread over 286 cars is ~38 mpg. Only 2 of those broke 50mpg. This represents less than 1% of all 2011 TDIs on fuelly. One of those 2 was a 1.4L and the other was from England... could be a smaller engine also.