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As that graph posted makes clear, there's just no cheating the laws of physics, irrespective of what country your vehicle was designed in. Drag increases exponentially with speed, so the key is to maintain a speed that optimizes drag and speed. For me that seems to be about 70 mph on long trips in my JSW.

Of course this varies with vehicle. My 2007 Suzuki GSXR 1000 doesn't seem to care nearly as much whether I'm going 70 or 120, but I think it has a smaller frontal area than the car.
 

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"I cant drive 55" so the song goes. With fuel being $3.75 I now drive 70 mph. On a bad day I still get better mileage than the newer tdi's, 47-50 on interstate.
 

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Hello, I have a 2000 Beetle w/ ALH diesel and a 5 speed that has 210,000 miles. I have driven the car to Guatemala Central America and back. I have driven en every type of condition you can immagine. I am from Florida. I drive no more than 5 mph over the speedlimit (in the US). When I drive hard in the mountains and use the turbo a lot I get between 32 - 37 mpg. Flat out on the hwy I have gotten as high as 51 mpg, but only for one tank, and never achieved that again. I am in NC right now and I have gotten between 40 and 42 mpg but my cruse contro has not been working this whole trip. Cruise makes a few mpg difference. I am writing this email from the waiting room of a VW dealer while the cruise control and new injectors I just installed get programed correctly. I hope this service is going to give me better mpg.

Hope that helps some.
 

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While i don't get the opportunity to take extended highway cruises, the few times I have (2 hours or more), I've found that my mpg at a steady 78-80 MPH using cruise control is mostly depended on headwinds. Driving south of Chicago toward central Illinois, headwinds can be pretty stiff, which is probably why there's an enormous windpower farm along the way. In these conditions, I'm lucky to get better than 38 MPG. On a calm day, I can average right around 40-41 MPG. My best was 44.4 MPG, which was from central IL into Chicago and included a bit of stop-and-go getting into the city. I suppose it's important to note that these figures are all with less than 3500 miles on the odometer.
 

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I just drove a brand new Jetta (less than 1K miles at the start of the trip) from Boise to Salt Lake to Logan then back to Boise. According to the dash display, I got 44.6 MPG. That was mainly with the cruise set at 79. No AC, but not flat by any means.
 

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Just drove from Milwaukee, WI to Detroit for business rather than flying. Average speed on the GPS was 73mph and only used 1/2 tank. I can't say enough about my Jetta (2001). Not every car has the following like the TDI's do, there's good reason. Once you get one, your hooked.
 

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My data

All,
I have a 660 mile round trip commute on the weekends. I have been getting around 39 MPG driving the car "fast". My average trip speed is around 66 MPH which is a by-product of getting pinched in traffic (NYC/Conneticut) and making up for it by driving like a banshie when it opens up. The first part of my trip is by foot and can usually punch the cruise on the last half. If I settle down I pull off 45MPG on the cruise 65-70 MPH consistently. I have 6800 miles on the car already and I have had it 3 months.
I can also verify it will do 120 MPH without hitting a limiter. I run stock tire pressures....33 psi. Matt
 

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The wife and I have put 3600 miles on our new 2011 Jetta TDi in the last month! 90% highway. The mpg's we are getting are high 30s. When I drive it the cruise is usually at 85 and when she drives it 81. She gets better mpgs (for obvious reasons). The other day was very windy and that had a direct effect on our mileage.
 

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[QlolUOTE=dezel;28652]"I cant drive 55" so the song goes. With fuel being $3.75 I now drive 70 mph. On a bad day I still get better mileage than the newer tdi's, 47-50 on interstate.[/QUOTE]

Lol ! $3.75 a gallon in my dreams! I pay $9.36 a gallon.:panic:
 

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Once you get a TDI (2001 Jetta) you tend to get hooked. I enjoy driving and would be in the catagory of "Spirited". I spent a good share of my life racing, ATV's, gokart's and motorcycles and can appreciate a good performing car. The Jetta isn't a rocket or a Porsche but it does have something about it that is addicting. The TDI can run circles around the rest of the Hybrids and still get great mpg. Now I am starting to modify mine (no DOT inspection req'd in WI) so it turns out to be a fun project car without the DOT issues. At over 204,000 miles, I still enjoy driving the darn thing.
 

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Of course this varies with vehicle. My 2007 Suzuki GSXR 1000 doesn't seem to care nearly as much whether I'm going 70 or 120, but I think it has a smaller frontal area than the car.
Motorcycles are notoriously bad in aerodynamics. A stock Hayabusa has a Cd of .561 and 6.01 feet of frontal area. There are modern cars with a Cd as low as .3
 

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Those Golf mpg figures are great news. I'm seriously considering augmenting (not selling) my 2002 Jetta TDI with a 2011 Golf TDI but was concerned about the low in mpg. I have almost 290,000 miles on the car and have always gotten 50 - 55 mpg. The last few days I've tried driving in the high 50's and expect to better that. With the price of fuel going up daily the expected hit with a new Golf was hard to accept.http://www.myturbodiesel.com/forum/images/blue/editor/separator.gif

One of the things not considered n this thread is diesel longevity and lower maintenance costs. I don't go to the dealer so your experience with VW diesels may differ.
 

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Well I did my monthly fill up yesterday it was showing 70 miles left so I gave it a quick blast up the motorway. I realised as I was driving that I need some petrol for the lawn mower so I had to go back home for the can. Just before I arrived home it said 20 miles left. I got the can and started up and it showed 5 miles left, how as it lost 15 miles in the drive?

I proceed to the fuel station which is 4 miles away, I hadn't done half a miles and it showed 0 miles so I carried on. I get to the fuel station and tanked it as normal and it only took 54Ltr so I had 1Ltr left. I've always said that the fuel gauge drops of quite quickly once the fuel warning shows up at 50 mile.

Its gone back to the normal 42.76mpg by my calc with the warmer weather we are having.

 

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Motorcycles are notoriously bad in aerodynamics. A stock Hayabusa has a Cd of .561 and 6.01 feet of frontal area. There are modern cars with a Cd as low as .3
That is true, although the frontal area is so much smaller, the lousy Cd makes less difference than on a car with it's relatively huge frontal area. I suspect that on the GSXR in particular, the fuel economy is more related to revs than anything else. By comparison, the JSW never really revs much, but the fuel economy seems to deviate more as a result of aerodynamic drag, in spite of the fact that it has a much better Cd than the bike.
 
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