Are you getting bad MPG?

Went on a small trip this weekend to a BMX race that was a 3.5 hr drive each way. Filled up before leaving with half a tank and got 17.6 all city. After the drive up filled up again and got 20.6 and that was half interstate doing 66 mph acording to my gps and half highway doing 30-55 going through towns. That's the best I've got so far. Was using 87 octane non-ethonal.

 

Last tank was 369 miles befor the low fuel light came on. That's the best I've ever done. Usually it's only about 325-330. This last tank was 87 octane, 80% interstate, 50% cruise control, the other 50% was my lead foot teenage son..... Strange it got that far on a tank. Only difference was I filled up in Wheeling WV rather than here at home. But they have oxygenated/ethenol enriched there too. Must have been the new cabin air filter I installed!

369 miles, 17.721 gallons = 20.87 MPG.

 

All you guys need to fill up your tank at half way point instead of letting it run down to reserve over 3 fill ups and reports back what your MPG is. I consistently get better MPG at half tank over full. Google it, go to ecomodder.com, there is some credence to this theory.

 

I have a 4x4 Dcab SB OR with eibach 2.5" and 5100s. Just got 19.5 yesterday! Love that summer blend.

 

This is how I look at it.

For over 30 years, since the oil embargo of the mid-70s, airlines calulate the amount of jet fuel needed for the planned flight to reduce weight.

Now, as far as we are concerned, the less gas in the tank (@ 6.073 pounds per gallon) = less weight.

In the perfect world with everything (mph/rpms/head wind/drag/ect.) being consistent, the amount of gas in the tank being the only variable, your mpg should go up as you travel further.

 

MY first taco was a 2wd dcsb OR pkg and got around 17mpg city 21 hwy.

I now have a 4wd DCLB and get 14 to 17 hwy and 17 to 20 hwy depending on conditions and how I drive. best thing i did for better mileage was to get the ecometer, it gives me instant feedback as to how I drive and what uses the least amount of gas.
http://www.summitracing.com/parts/ATM-9100/

 

Yes, thats intuitive. However, less gas in tank means more room for liquid gas to turn into vapor which means less MPG. Less gas in tank also changes the suspension geometry and depending on where the fuel tank is, it means less traction, which in turn means less MPG.

 

Interesting thought but ... .... I really don't think that the "less gas in tank means more room for liquid gas to turn into vapor" holds true ..... although I am not an engineer, a liguid gas under pressure is going to the fuel injectors isn't it? I know there is atomizes but isn't it liquid up to that point? There isn't any vapor in the fuel lines is there?

Now, as far as the less traction idea ... that may be stretching it a bit. I don't think that this vehicle going down the highway at 60 mph is going to lose a hell of a lot of traction as it loses what little weight it loses as fuel is used. I mean 21 gallons at a little over 6 pounds a gallon comes to a tad over 126 pounds topped off.

Besides I was always under the impression that more traction meant fewer mpg. Case in point .... a wider tire gives you more traction I am guessing but it also creates a greater road to tire surface which creates drag.

Anyway ........ I got 27 mpg ( 103.4 miles/3.832 gallons=27) yesterday on the highway at 70 mph so I'm happy.

 

You need to pick up the latest copy of Car & Driver and read the article about hypermiling a Ford F150 across America. Among other things, those guys take 30 minutes to fill up the fuel tank to minimize vapors. Do a simple google search and go to ecomodder.com, there is plenty of literature on vapor in fuel tank and how that is bad.

126 lbs might be insignificant to affect traction, but... it depends on what the weight distribution is. If 80% of the weight is in the front and the fuel tank is in the back, then the 126 is a lot more significant than if the weight was more evenly distributed. The first lamborghinis in the 1960s had a fuel tank in front that went light as fuel was used up causing all sorts of handling problems. Again, its well documented and google should turn up something if you want to search.

 

Well, thanks for educating me .... one can never stop learning .... I love Google as well as the next person .... I'll leave it at that .

 

i just got my 11 v6 dc sb trd offroad with 500 miles on it litarely a week old i got 18 average during the week with the ac on and took a lil road trip "130 miles one way" got 18 average on the way with ac on and it was mostly highway going through some mountains and got 20.13 on the way homw with out the ac on ...not bad im happy with that for bein a new truck and driving 75,80 the whole time

 

average around 16 to 18mpg, depending on my driving habits

 

(im listing only parts that might affect mileage) K&N intake kit, Doug Thorley True-Tri-Y Header, URD MAF Cal., cherry bomb glass pack......all of this is on a 2TR-FE, and have gotten over 30 MPG's on mostly highway trips, average around 25-28 in town with maybe some mixed highway in there.

 

Over 20 with my v6

 

Prerunner...

 

Just got back from a 1600mile ++ road trip and was averaging 24.3-25.6 MPG 65-70 MPH mainly was on Utah and Arizona gas, once I got back to SoCal the MPG dropped to 19-20
these of course are Hiway miles, forget trying to get "good" city miles.

 

As an update to my post many pages back, my entire fuel efficiency history is document via Fuelly.

2010 Double Cab V6 MT TRD OR.

 

I get 19 - 21 in the winter and 23 - 25 in the summer. Use the 4x4 a lot in the winter. I find changing the tires from snow to summer even same size makes a difference.

 

I got 21 this weekend.

 

Pushing 20 now. Mostly highway. Just got 21 this last fill up. Ran some Sea Foam through this tank. I think that helped a bit. Will probably put a CAI on in the near future. That along with the exhaust I'm going to be putting on will help also.