I have no trouble what so ever getting 50-52 mpgUS @ 70s- low ~80s mph in my 97 Passat TDI tank after tank . I don't see that it would be a lot lower than that if I were able to push it to 90 mph for any length of time . . And I always see low to mid 50s mpgUS in it on city only loops around Denver . Have achieved low 60s mpgUS several times in B4 Passat TDIs and A4 Jetta TDIs on city only loops in Denver and in southeastern coastal NC lower speed only loops .I could see 50mpg being "awesome" at 90mph but that would mean your ALH is inside a velo bike.
Your tank of diesel 2 got you to almost 1,000 miles at 90mph?
I'm calling bull****.
Not sure about Jim Martin's numbers, but rotarykid has been an MPG leader for years, and fully documents his MPG. Just b/c your FE doesn't match his isn't really cause for skepticism. My GF has had two different Jetta ALH's, one a Mark IV 1999, the other a 2003. With similar driving conditions, the older had a "lifetime" average of 45MPG over mixed but mostly hwy driving. The newer one, with almost exactly the same conditions, got 54MPG on it's first trip, and has an average of 52 MPG so far. Same drivers, same roads, same fuels, etc. When I drive her car, I beat my 2003 Golf's FE numbers by 2-3MPG every time. Some cars do better than others, and some drivers can get the most out of their car.I'm a skeptic of your numbers as well rotarykid because if I apply the same unit conversion of Imperial gal to US gal, your numbers then match mine.
sorry, but that's impossible. I've owned a bunch of tdi's (1998,2000,2002,2004) and i've never gotten close to that.I got 71.1 mpg for 38380mi. with my 2000 Jetti TDI driving like a bat out of hell over mountain passes on the interstate highway system mostly in Colorado and Utah. Advancing the timing was the only alteration to a fully stock 125 hp. TDI. Most of my driving was in excess of 90 mph. I had the timing belt replaced and my car was re-set to factory specs dropping the mpg to 56...have not had the time to re-advance the timing..some trial and error involved.
You don't have enough info yet (and neither does anyone else). My mileage goes WAY UP in the mountains. Yours will be much higher too if your willing to exceed the unreasonable posted speed limits. In some cases exceeding 100 moh is easy while idling.sorry, but that's impossible. I've owned a bunch of tdi's (1998,2000,2002,2004) and i've never gotten close to that.
To get maximum mpgs ;
I use a rolling start out of the garage to start the engine when the engine is cold to avoid battery drain that costs fuel to recharge ,
I skip gears ( 1st , 3rd , 5th most of the time ) and use rpm matching to shift ,
I use "N" when ever possible especially on city loops and when the engine is still cold I kill the engine when coasting in "N" using built up energy to restart when acceleration is required ,
I look down the road to avoid ever if possible over accelerating just to have to brake ,
I install a lot taller than stock tires ( 205-215/75 __" ) along with low mass alloy wheels ( as much as 5"-6" or more taller than stock as much as will fit under the lower end of the shock spring platform without rubbing ) , This not only helps top gear but helps all the gears be taller . If care is taken on take off this one thing can make up to a 5-7+ mpg difference in achieved mpgs over stock tires & wheels . This kills takeoff but that isn't why I drive a diesel anything . This change also can/will under cartain conditions increase stopping distance so you must drive accordingly ........This isn't a modification ( as much as I do it ) that I would suggest to someone without specific driving skills or knowledge . You must know how to realign the suspension to raise the car above factory height as much as I do . A skill which I learned how to do when I drove and worked on race cars when I was young , a skill the average Jo's blow mechanic doesn't have . The extra strain of the taller gearing and advanced timing can/does lead to head gasket failure if pushed !!!
I install an air dam to keep air from getting under the car due the need to raise the car up to fit taller tires ,
And as described above a real biggie in achieving these numbers is the fact that I jack the timing to really early BTDC to maximize energy gotten out of every gallon of fuel .
By themselves most of these things don't add up to a lot of improved mpgs . But when added together these things can add up to a 10-20 overall mpg improvement . A small increase in tire size along with a moderate timing advance can get you an extra 4-7 mpgUS pretty easily . That is as far as most want to go to avoid the blown head gaskets and other modifications required to push things as far as I do . A 3-5 mpgs or more increase can achieved pretty easily with just extra care taken in how you drive ( using the shifting things I've spoke of along with care not to accelerate just to have to hit the brakes ) without changing a thing on the car .
I used to use a Garmin 700 series as the speedo & odo(the 710 is the only model that gives miles and tenths of a mile on the clock so is perfect to figure out actual miles traveled per tank). I used it every day for ~3 years attached to my display over the speedo before I settled on the larger screen 1400 series units I use now.... EcoRouteHD connected units can give miles and tenths when connected. But when not connected they round the miles....Or if you object to fiddling with the numbers at each fill-up, do it the elegant way; install a pulse frequency interface in the VSS line, calibrate the odo, then finally independently calibrate the speedo by reindexing the needle. An $85 solution and well worth it (to me anyway) to not have to use correction constants at fill-up and put up with an inaccurate speedo.