jazar10

Hey Guys I was wondering if im the only one here that gets better mpg doing 85 then doing 65. If i do the speed limit to a vacation house i have in PA (i live in jersey) it takes me about 2 hours and i use about 1/8 tank of gas. But, When I cruise there doing 85, i dont even nudge the needle when i arrive.

Anybody get the same? I know this isn't really a serious question, but just wanted to know your thoughts.

subvet

I recently went from s e GA to Miami. Running around 70 - 73 mph. Got 13.4 mpg. I have an 05 Lariat 5.4 I get 40 mpg on my HD.

CrashTECH

You won't get better MPG by going faster. To go faster you need to raise the RPM, to raise the rpm you need more throttle... more throttle = more gas.

Gas gauges are super inaccurate, especially above 1/2 tank. Ever notice how after 3/4 of a tank or so, it starts to drop like a stone but getting to 3/4 took forever?

jazar10

once in a while yes, but for some reason, whenever i do that drive, at that speed, i feel like it drops normal from full to 3/4

hcbph

Seems strange to me that going so much faster would use less gas. First off, assuming you're outside the prime torque range of the engine and the increased wind resistance, it should use more not less.

Only way to know for sure would be a proper test. Fill your tank at a known gas pump, let it go till it shuts off automatically then stop. Drive your route at one speed and fill your tank at a known gas pump when you arrive but prior to doing any running around there. Now go back to your starting point and do it again except go at your alternate speed. Compare the gas consumed each time and there should be your answer. Also do it as close together as possible to remove the possibility of any changes in gas blend (e.g. seasonal changes that occur).

It would be nice if it was true but I have my doubts.

Hatchetman240

You can determine this. In space faster is better because there is no resistance, but here on earth we are fighting resistance everywhere. Gravity and air cause this. Even the drag created by keeping your windows open vs closed can change things.

On the other side of that is power and engine efficiency. As we go up in speed our engines become more efficient (like changing gears on a bike, the peddle rotation is just as hard but it makes your wheel spin much faster) but our wind resistance becomes exponentially more difficult to penetrate. When you are over 200mph air becomes as hard to move through as water. That's why the new Veyron has 100 more HP but can only go about 5mph faster at those high speeds.

http://auto.howstuffworks.com/fuel-e...uestion477.htm

rockymtnrider

I've been messing with my driving speeds lately. I've been testing on a stretch of freeway to my parents cabin and at 75 I get right about 15 mpg. At 65 I get about 18. At 85 it goes below 15 maybe even 13. I think I get even better at 55 but that's just looking at the needle. I have seen the needle stay in one spot for the first 80 miles on more than one occasion too.

jazar10

weird. i babied my truck one week, got the 5.4 screw, and did all highway to school and back. Zeroed out my trip, refilled after the week, and only got 15.4mpg. No city driving whatsoever,unless you wanna count the 400 feet off RT 287.

Then i did the drive doing 85 and it took a little longer to fill my tank up [only like a day] and i fill at the same level left all the time

FrozenTundraGuy

2006 Screw XLT 5.4 2wd 6.5 bed 3.73 axle 17" wheels/tires

I've gotten 20 mpg a few times, temps around 50-60 degrees, no accys on, and driving like grandma on the highway. Normal driving in town gets 13-15 (lower with A/C on) and towing my 5500lb travel trailer can range from 9mpg (strong headwinds) to an average of 11-12mpg with no winds. I recently bought the ScanGauge II and have learned to increase my MPG by not using cruise at times and a lighter foot on the throttle. I also use Mobil 1 oil and have a K & N air filter. I'm planning to switch to Mobil 1 0W-20 on my next oil change to see if I can eck out a few more tenths of MPG.Everything else on the truck is stock. My sweet spot for optimal mpg is 55-60mph on my truck. Above that and the gas gauge goes to the left much faster!

Bruno82

Greetings and Salutations!

I'm a 2007 F150 2wd 4.6L V6 owner. I'm pretty obsessive about tracking my fuel mileage (for fun). I always top off and I write down my mileage at each fill up. I notice when I'm primarily driving on the interstate, I get about 23mpg. With mainly city driving, I get around 18. My average is 19.6mpg. That interstate driving is done about 65-70mph (my wife won't let me drive slow). On my next OKC to Dallas run, I'm going to try 60mph the whole way and see what kind of mileage I get. I wouldn't be supprised if I get close to 25!!!