My average MPG coming home from Charlotte this weekend. Took 64/49. 51mph average, 156 miles. 2.75 gallons of diesel, about $11.

[Edited on May 9, 2011 at 1:58 PM. Reason : anyone considering a VW diesel, I'd highly recommend it]

5/9/2011 1:55:28 PM

28.9....

driving my legacy gt Charlotte to Raleigh round trip.

still way better than the 18.9 i got with my Cherokee though

5/9/2011 2:27:43 PM

what's the main disadvantage of having a diesel car versus a gasoline car?

5/9/2011 2:37:20 PM

no significant disadvantages

the U.S. needs to get with it.

5/9/2011 2:42:25 PM

Limited selection of vehicles in the US... They are generally going to be more expensive to buy for a given year/chassis. Can't get diesel at all stations, so if you are in unfamiliar territory on empty you might get yourself in trouble. You should be able to avoid that though.

5/9/2011 3:02:54 PM

... yeah because diesel is really hard to find... you know people really should cater more towards diesel drivers and make specific stops for them along the highway...

Seriously the only draw back used to be the rattley noise of them but most companies have done away with that. And diesel fuel costs a little more then premium does now.

5/9/2011 3:43:16 PM

Quote :

"... yeah because diesel is really hard to find... you know people really should cater more towards diesel drivers and make specific stops for them along the highway... "

Actually, you don't know just how shitty it is when you're running on fumes at 2:00 am and the last three places you stopped don't have diesel.

I remember when my family bought our first diesel car back in the mid '80s...the situation was that much worse.

5/9/2011 4:00:44 PM

seriously?? hmm i guess i haven't really looked that hard. I think i would feel awkward to go to a truck stop and get gas at the big pumps.

5/9/2011 4:02:52 PM

Quote :

"51mph average"

ouch. what is it at 70-80 mph? 40mpg?

5/9/2011 4:08:30 PM

Should be about 58-65 mph

5/9/2011 4:40:53 PM

Keep in mind that was going through towns along the way, 55 in between, down to 45, then 35 and back up (also with stop lights). I did let the speed drop 10 under apexing hills, and let it build back up to 5 over on the way down.

My route to work has 65/70 mph speed limits, and I'll fall in a line of traffic to draft. Best so far (I40 and 264, around 50 mile round trip) was 55 MPG but generally its 42-46 MPG if i'm not trying to squeeze the best out. It takes some effort to be gentle on the accelerator and sometimes its nice to set the cruise. Without other cars to follow at 70+mph it is indeed closer to 40 MPG.

The temperature makes a huge difference. This winter I was getting more like 42 MPG on the way to work trying hard. Not sure why its not as happy in cold weather.

Next time I go I will take 40 and 85 to see what happens. Its a longer route and higher speed limits, no stops, but still takes almost exactly 3 hrs.

[Edited on May 9, 2011 at 5:01 PM. Reason : d]

5/9/2011 4:56:57 PM

I made that drive over Easter weekend and got around 36 mpg in my old Integra with the windows down the whole time (hello drag). I was impressed with the mileage I had.

Nicely done for your Jetta though!

5/9/2011 5:01:21 PM

That's pretty good... My old teg did about the same, but I did not have the vtec. My buddy has a 4dr GSR and says he gets around 30 on the highway, I wonder if he has something going on that's hurting his mileage some.

I have the Golf. I think the Jetta might do a little better, it has a more sleek rear end where the Golf just stops.

[Edited on May 9, 2011 at 5:05 PM. Reason : always an edit]

5/9/2011 5:03:42 PM

Right in line with what i got when i drove a prius. i was averaging 65mph though.

5/9/2011 6:35:19 PM

16.7 mpg Premium

5/9/2011 6:54:29 PM

i have a GSR also, and I average around 30 mpg mixed driving.

5/9/2011 11:58:22 PM

Quote :

"This winter I was getting more like 42 MPG on the way to work trying hard. Not sure why its not as happy in cold weather."

I wonder if diesel has a "winter blend" that affects gas mileage as gasoline does?

Quote :

"Without other cars to follow at 70+mph it is indeed closer to 40 MPG."

I get around 36 MPG at 70MPH in my Civic. I console myself with gas being cheaper than diesel and by rolling around in the $12,000 I saved over buying a TDI Jetta. (ok...I admit I got my Civic dirt cheap and the comparison would be crippled if I had paid anywhere close to sticker price).

[Edited on May 10, 2011 at 4:42 PM. Reason : s]

5/10/2011 4:40:16 PM

do people not realize that cold air is more dense? You are making more power while cruising in the winter thus using more gas. Cold weather effectively makes your small engine act like a bigger engine.

What the hell would you winter blend diesel with?

5/11/2011 11:26:29 AM

At cruise drag equals power. The only way there would be more power being made is if there was more drag. Are you saying you use more power to push through the more dense air?

A diesel does not run at a stoichiometric ratio, so I don't see why it would need to burn any more fuel with denser air.

Maybe it is because the engine loses heat faster in cold air, and burns more fuel as a result of the lost energy.

[Edited on May 11, 2011 at 12:14 PM. Reason : Or it is less efficient with thicker air flowing through it]

5/11/2011 12:05:00 PM

^^in areas around the country diesel is sold with an anti-gelling additive during the colder months

5/11/2011 12:48:06 PM

Quote :

"The temperature makes a huge difference. This winter I was getting more like 42 MPG on the way to work trying hard. Not sure why its not as happy in cold weather"

Quote :

"I wonder if diesel has a "winter blend" that affects gas mileage as gasoline does?"

Quote :

"At cruise drag equals power. The only way there would be more power being made is if there was more drag. Are you saying you use more power to push through the more dense air? A diesel does not run at a stoichiometric ratio, so I don't see why it would need to burn any more fuel with denser air. Maybe it is because the engine loses heat faster in cold air, and burns more fuel as a result of the lost energy."

Quote :

"^^in areas around the country diesel is sold with an anti-gelling additive during the colder months"

Dr Pepper came closest to the answer...it has to do with gelling in cold weather. Diesel fuel is in essence nothing more than more highly refined fuel oil. Standard diesel is closest to #2 fuel oil.

It used to be that you could go to any truck stop and tank up with either #1 or #2 diesel. #1 was most resistant to cold weather gelling and precipitation of paraffins. #2 had a higher paraffinic content and thus contained more energy...it's also why it gelled up in really cold weather. In different areas, depending on supplier, you could get blended #2, which contained either #1 or some kerosene in amounts proportionate to temperature.

Now, diesel fuel, like gasoline, is blended for seasonal use. What you get in winter is a different grade of distillate, less subject to gelling, but also containing less thermal energy.

5/11/2011 1:26:10 PM

Quote :

"A diesel does not run at a stoichiometric ratio, so I don't see why it would need to burn any more fuel with denser air. "

good point i'm brain farting... thats why gas cars get crappy mileage in the winter. Same thing with cars getting better mileage (with no power) at altitude

But Newer VW tdi's do run a maf sensor so obviously they count how much air is being taken in at a given time.

5/11/2011 1:56:26 PM

Quote :

"thats why gas cars get crappy mileage in the winter"

I'm not following your thought here that driving in colder weather means you use more fuel. I understand that denser air contains more oxygen so you would also have more fuel. But unless you're running full throttle I don't see how this makes a difference. If you're making extra, not needed, power b/c of the air density then the natural thing for the driver to do is not open the throttle quite as much, negating any differences in fuel consumption.

[Edited on May 12, 2011 at 8:26 AM. Reason : k]

5/12/2011 8:25:45 AM

42.3 - my mileage coming home from raleigh to greenville SC last trip. Sunday night, mild traffic, I40-I85. Average speed somewhere around 70 im sure, i drive 10 over and did not stop. Oh and i was on cruise control.


mid 90's honda civic ftw.

[Edited on May 12, 2011 at 8:50 AM. Reason : .]

5/12/2011 8:48:47 AM

Picked it up a bit this time, highways 49/64 again, 58.7 mpg! Still around 50-51 mph average. Had a bit more weight in the car this time and ran into some rain. Not sure what to attribute the difference to, probably a combination of having more practice driving it efficiently and the engine being a bit more broken in. I feel like I attacked the hills better this time, some shorter hills you can just decel the whole way up (55 down to 45 or 40 mph), and longer ones are better to stay at more efficient RPM (hold 50 mph) since the engine sees a bit more load. Looking forward to breaking 60 mpg on the same route. I'm sure it won't be a problem driving to the beach or something since its nice and flat, and there will be plenty of traffic to draft. Should be able to do 60mpg at 70mph in that situation. I'm hoping at least.

7/25/2011 7:25:37 PM

i'm going to negate all this mpg happiness. 10.3 mpg average, 6200 mile round trip 3 weeks ago. mix of highway (usually 70-90mph), lots of high mountain passes, and a lot of off road. a similar trip last summer was 10.9 mpg, only difference being tires two inches smaller in diameter and slightly less mountain driving and lower passes. i don't really care though, i'd rather drive what i want in the manner i want and take the expense. guess that makes me an eco asshole.

Quote :

"I think i would feel awkward to go to a truck stop and get gas at the big pumps"

at most, you can't unless you modify the filler neck. even on light duty (3/4-1 ton) trucks. the truck stop pumps aimed at medium/heavy duty trucks have larger nozzle diameters that won't fit most passenger car fillers. on the two diesel trucks i've owned, i simply took a big screwdriver/hammer and knocked out the little restricter order to use the big nozzles.

[Edited on July 25, 2011 at 9:17 PM. Reason : .]

7/25/2011 9:00:45 PM

the big truck pumps do work on my truck (f250) but you have to feather them because the pressure is way too high

7/25/2011 10:27:16 PM

Quote :

"I did let the speed drop 10 under apexing hills, and let it build back up to 5 over on the way down"

F that

7/25/2011 10:35:23 PM

^^probably modified by a previous owner i would imagine. though, i have seen some newer (like 05+) light duty diesel trucks come from the factory able to accept the bigger nozzles. most can't. not sure the reasoning.

7/25/2011 11:51:18 PM

39.2mpg on one tank of gas going to and from the beach last week in my saturn...regular gas, 67-68mph

coming back from the mountains two months ago i got 42.8 with 3 people, 2 dogs, and backpacking gear...average speed in the upper 60s

7/26/2011 8:05:45 AM

Driving down to Hilton Head Island the other weekend traffic was light and I averaged around 78-80 mph but only got 25 mpg (on the dot). On my return trip I got stuck in traffic for 90 minutes (went 10 miles) and then traffic on I-95 was heavy so I was using the right lane to leap frog assholes in the left which necessitated the occasional run up to 90-95 mph. I probably averaged around 75 and yet somehow I got 27.5 mpg on that tank.

What in the fuck went on there?

7/26/2011 9:08:42 AM

^going uphill vs. going downhill

7/26/2011 6:06:16 PM

^not in this case. Regardless you're suggesting that the beach is at a higher elevation than Raleigh, lol. (though I suppose you might not know I live in Raleigh).

7/26/2011 9:18:59 PM

my b u right I missread that

[Edited on July 27, 2011 at 7:26 AM. Reason : it was also a bad joke]

7/27/2011 7:25:51 AM

haha, well if I had been going to the mtns you would have been correct.

7/27/2011 1:48:56 PM

In light traffic you are breaking all the air yourself. As speed increases past 55mph drag increases exponentially. At 85 you are doing a lot of work moving air. My guess is that on the return trip you more than made up for puttering along for that 10 miles by drafting a sea of cars.

7/28/2011 4:29:50 PM

^Yeah I know about all that, but there's no way that could have been the only factor. I mean my best highway mileage (for a tank) is 33 mpg. And that was averaging close to 80 (though almost always in a pack with cars). Seems like such a huge swing.

I will say that I always try to join up with a speeding SUV whenever I can. The bigger the better

7/28/2011 4:41:09 PM

maybe there is a giant magnet near your house

7/28/2011 4:56:26 PM

7/28/2011 5:49:25 PM

2012 Civic LX automatic (wife's car) - cruise set at 50 mph on 401N from Lillington to Fuquay, a/c on, econ mode on:



[Edited on July 28, 2011 at 9:48 PM. Reason : 55 mph = ~46 mpg]

7/28/2011 9:46:59 PM

If you don't fill up at the same station, you might be getting different amounts of fuel when the pump cuts off. The gas pumps at each station can flow much differently either through natural Cv in the design or electrically regulated flow. I could get an extra half gallon in my 4runner and golf at some stations after the fuel backpressure was so high it would cut off prematurely; whereas stations with slow pumps were able to fill up the tank all the way to the filler hose. Using the same pump generally rules out a lot of that variation.

Also, you can't count on your mpg being very accurate under 50 miles or even 100 in some cases, if that's the case that extra half gallon can shoot down any perceived gain. Use as much of a full tank as possible to get the most accurate average mileage per trip.

7/29/2011 10:10:37 AM

^yeah maybe it was the station difference. Since gas is so expensive these days I usually fill up my tank with the pump on the slowest setting (unless I'm in a hurry). However the station that gave me the crappy mileage is the same station I always use around Raleigh.

^^Nice, but seriously who has the patience to travel somewhere only going 50?

[Edited on July 29, 2011 at 12:39 PM. Reason : though i guess those towns are near each other? I dunno NC small town geography]

7/29/2011 12:37:57 PM