Taylors drive a Passat diesel 1626 miles on one tank - 84 mpg (US), 39 mph avg*

[MetroMPG]

In driving from Houston, Texas to Sterling, Virginia, the Taylors drove 1,626 miles on a single 19.322 gallon fill of clean diesel. That equates to an average economy figure of 84.1 miles per gallon.

The Taylors were determined to make it a proper test too, rather than making it too easy. To that end, all the driving was done during the day in normal traffic conditions, rather than at night. The car was completely standard--a 140hp, 2.0-liter TDI, with a six-speed manual transmission--with 120 pounds of luggage in the trunk. The Taylors took turns at driving, and drove no more than 14 hours per day.

More: 1600 Miles On One Fill? Meet The Taylors And Their VW Diesel

* Assuming they drove 14 hours each of their 3 days on the road, that's an average speed of 39 mph.

[Stan]

The mpg is really impressive until one considers their average speed of 39 mph. Several years ago my wife drove our Golf TDi from Washington State (exit 59 on I-5) to near San Francisco doing 55 on cruise control on the flats, and slowing to 50 on cruise going up the passes...and averaged 72 mpg. My dad had died and my mom wanted me to take his old Ford truck home ('76 E250 with carb'd 460 CID gasser ), which itself averaged 11 mpg on that trip.

TDi drivers quickly learn that with a manual you can plan an mpg by subtracting your mph from 120 on flat ground. For the Taylors that works out to about 120-39=81, so they did a little better than nominal. Maybe they did a little p&g along the way...

[MetroMPG]

Originally Posted by Stan

The mpg is really impressive until one considers their average speed of 39 mph.

Exactly. I mean, it's still impressive, but also relatively slow.

That's why I always ask people about average speed when they post eye-popping fuel economy numbers (and why I always post mine).

People need context to understand just how "realistic" the results are (and everyone brings a different definition of what's a "realistic" average speed).

[user removed]

I have to agree, it's not that hard to get unreal mileage if you average 22 MPH. I think I got past 90 on my brothers 1990 Civic with TB injection and a 4 speed. I was using a dvom to read the voltage of the sending unit and many times after a 18 mile round trip the gas in the tank heated up enough to actually make the second reading higher than the first. Had to measure the tank temperature and wait until it was the same to get decent readings.

regards
Mech

[Diesel_Dave]

I'm not sure if anyone else has posted this yet, but I saw this articel on Fox News today:
Couple squeezes 84 MPG out of diesel Volkswagen Passat | Fox News

[tjts1]

I wonder how much gas was wasted because other drives had to slam the brakes then re accelerate because these people were blocking traffic.

[Diesel_Dave]

39 mph average may not necessarily be as slow as it sounds. I think I read that the EPA highway cycle averages about 45 mph.

[Sven7]

Originally Posted by tjts1

I wonder how much gas was wasted because other drives had to slam the brakes then re accelerate because these people were blocking traffic.

I wonder how much gas is wasted from people driving full size pickups 85mph everywhere they go.

If there was no one around I can see doing 40 ish. Yesterday I got away with P&EOC'ing from 40 or 45 to 65. People didn't slam on their brakes so much as just move into the adjacent lane.

[WD40]

Originally Posted by tjts1

I wonder how much gas was wasted because other drives had to slam the brakes then re accelerate because these people were blocking traffic.

This is what you honestly expect us to believe they experienced?
On my worst day of holding back traffic ( doing the speed limit ) the worst I have ever experienced is the "professional" truck drivers pushing me (literally feet away) and then passing while giving the one finger salute, and then the finale .. cutting me off while they get back into the "slower traffic keep right lane"
Mostly its the professionals that give me cause for concern, the average driver happily follows someone doing the limit or slower as they are usually multi tasking anyway.

[Diesel_Dave]

I just found the number, the average speed of the EPA highway cycle (highway fuel economy test- HWFET) is 48.3 mph.