Gas Mileage Calculation

That sounds about right. I used to do my calculations like that before I got my Scangauge. Right now my avg. is around 19.2mpg and I drive about 65mph. I am pretty much stock like you.

You need to do atleast a week avg to compensate for pump "full" variations.

ruebarb said:

You need to do atleast a week avg to compensate for pump "full" variations.

Click to expand...

Could you go into a little more detail? Do you mean top it off every week then calculate? I drive quite a bit and usually fill up every 10-12 days.

That sounds correct. I don't use the scanguage for averages, just for immediate info to help tweek my driving. You may be able to increase it slightly if you can find roads that are relatively level, no lights/signs, and can hold a very steady speed between 35-45.

OK, I feel a little better now, I kind of figured that those were scanguage numbers. My commute is 10 miles cruise control set at 50mph, relatively flat terrrain, I just thought I would get a little better than what I am. I do still have low miles, as I've heard mpg increase after vehicle is well broken in around 10,000 if I recall.
IMO you cannot have too much info on what your engine is doing, so I guess its time for me to get a scanguge myself. I have been fairly impressed with what I have read about them...

watch out for us Canadians too in here.....We have a bigger gallon than you guys and we also have to convert ours from liters to gallons ......Kilometers to miles and then factor in the difference in volume from US Gal to Imperial Gal. Using our imperial gallon calculation of 4.54liters/gal I am getting an average of about 24mpg. The highest i hit was a 25.3 on a four hour road trip. The worst was 4wheeling back logging roads and some gravel pit time with buddies....You know the drill. That one came up at 16mpg......(and worth every penny I might add). But down in the states i am lucky to hit 20mpg cruising at 65mph. We did a run down around Bar Harbor (Coast of Maine) and we dottled around under 50mph most of a tank full and managed a 21...... Good luck.

Best fuel consumption mod you can do is to wear lighter shoes while driving!!!!!!

First, I always calculate my mileage. My calculation is always within a few tenths of the scanguage figure. I can get 18+ around town if I drive smoothly.

mising said:

OK, I feel a little better now, I kind of figured that those were scanguage numbers. My commute is 10 miles cruise control set at 50mph, relatively flat terrrain, I just thought I would get a little better than what I am. I do still have low miles, as I've heard mpg increase after vehicle is well broken in around 10,000 if I recall.
IMO you cannot have too much info on what your engine is doing, so I guess its time for me to get a scanguge myself. I have been fairly impressed with what I have read about them...

Click to expand...

Avoid cruise control because it will kill your mileage. It sounds crazy, but it is true.

A scanguage is a great investment provided you don't throw it out the window when you see the numbers drop to .7 mpg when you hit the go pedal.

NBFJCruz said:

watch out for us Canadians too in here.....We have a bigger gallon than you guys and we also have to convert ours from liters to gallons ......Kilometers to miles and then factor in the difference in volume from US Gal to Imperial Gal. Using our imperial gallon calculation of 4.54liters/gal I am getting an average of about 24mpg.

Click to expand...

That could explain a lot. I never thought to look where folks were posting from...

podex_equus said:

Avoid cruise control because it will kill your mileage. It sounds crazy, but it is true.

A scanguage is a great investment provided you don't throw it out the window when you see the numbers drop to .7 mpg when you hit the go pedal.

Click to expand...

Hmmm...I always heard Cruise Control was supposed to help by keeping a steady speed, but I will try leaving it off for the next month or so and see what happens.

As far as the .7mpg I understand that all too well, I can actually watch my K5 Blazer's fuel gauge go down as I floor it...I just cant get over the full throttle sound of a V8 through Flowmasters!!

That's about right. I have the 6M full time 4wd and usually get about 14mpg. This weekend however I got almost 22mpg on a road trip (80% interstate, 10% grid lock, 10% heavy city traffic). I got 295 miles on 13.6 gallons of gas. The way I did it was by accelerating as lightly as possible while short shifting--keeping the engine below 2k rpm. While on the interstate I kept the speed around 60mph. I also turned off the engine at long stop lights. I was certainly the slowest person on the road, but I didn't care. I was just trying to see what was possible with the 6MT. My FJ has things that reduce it's mileage such as 265 70 17 BFG T/A KO (at 37psi all around), a roof rack with Yakima crossbars and bike attachments, and a heavy front skid plate. I think you guys that are completely stock with 5AT should be able to get a few more MPG than me. Maybe 24MPG is possible.

mising said:

Hmmm...I always heard Cruise Control was supposed to help by keeping a steady speed, but I will try leaving it off for the next month or so and see what happens.

As far as the .7mpg I understand that all too well, I can actually watch my K5 Blazer's fuel gauge go down as I floor it...I just cant get over the full throttle sound of a V8 through Flowmasters!!

Click to expand...

Give it a shot, your eyes can see the overpass and slowly adjust the throttle accordingly. Cruise control just says, "oh @#%&!" and hits the gas when the vehicle starts slowing down. Flat terrain should be a nonissue, but it's still worth a try.

mising said:

Could you go into a little more detail? Do you mean top it off every week then calculate? I drive quite a bit and usually fill up every 10-12 days.

Click to expand...

Each nozzle you use at a gas station is going to stop dispensing gas at a different "full". So when you fill your tank, you know how much gas you put in, but we assume the nozzle clicks off at 19 gallons in the tank, which is not the case. So one trip (exaggerated) you may get 22mpg and then next trip 13 mpg. By averaging the mpg from a few fill-ups, you are allowing the values to correct themselves.

That's about what I got up to around 1500 miles. At 1500 I started winding the thing up a-bit with a few WOT episodes and in general, just drove harder. It started to loosen up and by 2500 miles I was getting 300 miles or so on the tank (19.5). It's actually getting about 20.5 now with 3000 miles. I really need to get on it a little and wind it up/out again, but with the price of gas?? Ron

mising said:

OK, how are all of you calculating your gas mileage?

I use the miles driven divided by gallons used method. For example, every time I fill up, I reset my trip odometer to 0. Next time I fill up, I divide that reading by the amount of gas I put in the tank to fill it up again.
246.7 miles / 14.8 gallons = 16.66 miles per gallon

My problem is that I never have been able to get over 17.5 avg mpg between fillups.

I drive very conservatively, rarely go over 65 mph, my truck has the stock BFG 265/75R16 tires, auto trans and roof rack and has about 3000 miles on it. What am I doing wrong?

I keep reading where members are getting up to 22-23 mpg?!

Are some of you reading peak mpg off of your scanguage, or is there a fault in my calculations?

I would just like to get a little closer to the low 20's mpg if possible.

Thank you for any input.

Click to expand...

i do the same reset odo every time than when i fill up i take the miles driven divided by the number of gallons i put in and the best i have ever gotten was 17, and i am still stock

mising said:

OK, how are all of you calculating your gas mileage?

I use the miles driven divided by gallons used method. For example, every time I fill up, I reset my trip odometer to 0. Next time I fill up, I divide that reading by the amount of gas I put in the tank to fill it up again.

Click to expand...

I do it exactly like you do. To be accurate, you must fill it to exactly the same point every time, and different pumps will automatically shut off at different places depending on the pressure and speed of the pump. No problem for me, since I always top mine off slowly to get that last 1.5 or so gallons in, and thus I can visually see that I fill it to the same place every time. Some folks don't like topping off though.

I used to get over 20 mpg on the highway all the time when it was stock; now with steel wheels, 33" tires, steel bumpers & sliders, winch, Hi-lift, etc. I can only approach 20 with a strong tail wind.

Way too many factors affecting fuel economy to be able to make meaningful comparisons between trucks IMO.

My FJ has the same tires,wheels,trannsmission, and miles as yours. I also rarely do over 65mph. My last two tanks have been in the 18 mpgs with 90% suburban driving.I can do about 20mpg on the freeway. How's your tire air pressure. I think the book says 32lbs. I just put mine to 38lbs to see if that affects anything. Handeling/ stopping will suffer to some degree though.

mising said:

OK, how are all of you calculating your gas mileage?

I use the miles driven divided by gallons used method. For example, every time I fill up, I reset my trip odometer to 0. Next time I fill up, I divide that reading by the amount of gas I put in the tank to fill it up again.
246.7 miles / 14.8 gallons = 16.66 miles per gallon

My problem is that I never have been able to get over 17.5 avg mpg between fillups.

I drive very conservatively, rarely go over 65 mph, my truck has the stock BFG 265/75R16 tires, auto trans and roof rack and has about 3000 miles on it. What am I doing wrong?

I keep reading where members are getting up to 22-23 mpg?!

Are some of you reading peak mpg off of your scanguage, or is there a fault in my calculations?

I would just like to get a little closer to the low 20's mpg if possible.

Thank you for any input.

Click to expand...

I'm one of the lucky ones that gets great mileage and my FJ is stock as well, except I don't have a roof rack. I calculate my mpg the same way you do.

If your going 50 mph with the cruise control on and driving on flat ground, you should be getting a whole better than 17.5 mpg. What rpm are you running at 50 mph?

DEWFPO