Real World MPG

[1engineer]

I don't know how important MPG is to other generation 4Runners, but in the 5th Gen section there are countless threads about this very subject. The problem is not many people know the huge variation in mpg you can get based on driving habits and environmental factors! For example, did you know your fuel could have a power density difference by as much as 4%? That would be almost 1 mpg difference on a 20 mpg vehicle from the same gas from the same station! Anyway, for those of you that really care about the efficiency of your vehicle read this Real MPG Part 2: It?s Report Card Time - Motor Trend article on how they test it right.

 

[77Bronc]

I don't know how important MPG is to other generation 4Runners, but in the 5th Gen section there are countless threads about this very subject. The problem is not many people know the huge variation in mpg you can get based on driving habits and environmental factors! For example, did you know your fuel could have a power density difference by as much as 4%? That would be almost 1 mpg difference on a 20 mpg vehicle from the same gas from the same station! Anyway, for those of you that really care about the efficiency of your vehicle read this Real MPG Part 2: It?s Report Card Time - Motor Trend article on how they test it right.

Good read. I can get great mileage variances on my 2012 Expedition with a 5.4L engine. One particular brand of gasoline gets better MPG than the other.

My cumulative average on the 2015 TP Is about 18.3 with less than 3K miles. This is good because I could never get better than 14.5 in the 2005 F150

77

 

[cashmoney]

If 1mpg bothers your budget or your psyche you should quit checking it or redo your budget. Assuming you can use the complete 18gal in the tank, the difference between 15 and 16mpg is 18 miles. That won't even get me to the office. That's like a $1.25 a week or $65/yr. I could drink one 12pk a week less and save over $600/yr.

 

[1engineer]

Understood. You do realize that mpg threads are some of the most popular in every subforum though. I just wanted to post that so hopefully people will realize finding an average mpg for a vehicle is not as easy as driving to the beach and checking their mpg one time. The more you know lol.

 

[KidVermicious]

Good read. I can get great mileage variances on my 2012 Expedition with a 5.4L engine. One particular brand of gasoline gets better MPG than the other.

My cumulative average on the 2015 TP Is about 18.3 with less than 3K miles. This is good because I could never get better than 14.5 in the 2005 F150

77

I have seen as good as 17.5mpg with the 5.4 in my '01 F150, that was summer gas on stock tires and me driving like grandpa. Right now I'm getting more like 13. :cry2:

 

[Wolf_Girl]

My '67 caddy averaged 16 on the hwy, I was pleased. However even more so with a carb'd vehicle it depends on your foot. I'd think that's the direct cause and effect, no? LoL And yeah I suppose gas too. Higher octane fuel sure seems to give more get up 'n go, but I also read too much of the same is bad too (Chevron all the time, etc) because their additives start to build up. So switching around but never getting the cheapest gas seems to work well.
My fiance gets awful mpg in his '96 Dodge ram because he's a lead foot.
I average 22-23 mpg hwy in my Toyo with 5.29s and 33 M/Ts. Love that OD button. Haven't paid attention in town because I don't fill up often.
My 1st gen spoiled me rotten <3

 

[KidVermicious]

Higher octane fuel sure seems to give more get up 'n go,

This is a really pervasive myth, and not really true.

When you hear people talk about pinging or knock, they're talking about the air fuel mix in the cylinder igniting before the spark plug fires due to compression from the closing piston. The octane rating of gasoline is just a measure of the gasoline's ability to take that compression without spontaneously igniting, nothing more. It does not indicate any greater energy potential than lower octane gas.

To confuse the matter though, higher octane does let a motor run higher compressions in the combustion chamber, and more compression means more bang when it does ignite. But that's the motor, not the gas, and if your motor is not built and/or tuned to take advantage of that higher octane fuel then paying for the higher octane is just throwing your money away.

 

[Wolf_Girl]

This is a really pervasive myth, and not really true.

When you hear people talk about pinging or knock, they're talking about the air fuel mix in the cylinder igniting before the spark plug fires due to compression from the closing piston. The octane rating of gasoline is just a measure of the gasoline's ability to take that compression without spontaneously igniting, nothing more. It does not indicate any greater energy potential than lower octane gas.

To confuse the matter though, higher octane does let a motor run higher compressions in the combustion chamber, and more compression means more bang when it does ignite. But that's the motor, not the gas, and if your motor is not built and/or tuned to take advantage of that higher octane fuel then paying for the higher octane is just throwing your money away.

Word! My Caddy's big block is a high compression motor (Forgot comp test numbers but somewhere around 10:1.. Gawd I miss that power, she's still in NM) so she complains when I don't feed her premium, but hey as long as gas is below 2 bucks a gal why not burn out that carbon with some high octane once in a while in our daily drivers?
You're right though, that premium doesn't make for better mpg.
But it may make for a cleaner healthier running engine... which in turn.. makes for better mpg?
:

 

[Twan]

But it may make for a cleaner healthier running engine... which in turn.. makes for better mpg?
:

Nope. Octane rating has nothing to do with that at all. Sounds like you're just buying into the snake oil that is the "ultra super premium patented" detergent blends they advertise.

 

[MtnT4R]

Interesting article. Made me think of something I learned about a few years ago: Fuel temperature affects the volume you actually pay for. Maybe a small amount, but significant enough that companies have designed Automatic Temperature Compensation pumps.

http://www.fairbanksglobal.com/fuel-temperature-report.html

 

[m85476585]

Word! My Caddy's big block is a high compression motor (Forgot comp test numbers but somewhere around 10:1.. Gawd I miss that power, she's still in NM) so she complains when I don't feed her premium, but hey as long as gas is below 2 bucks a gal why not burn out that carbon with some high octane once in a while in our daily drivers?
You're right though, that premium doesn't make for better mpg.
But it may make for a cleaner healthier running engine... which in turn.. makes for better mpg?
:

There's more to it than just compression ratio. The 4runner's 4.0L is 10.4:1, and Mazda's Skyactive engines have a ratio of 14:1 on regular fuel! It sounds like they achieve that by taking measures to cool the combustion chamber between cycles.

Skyactive 2 is rumored to have a compression ratio of 18:1, and it sounds like they will be basically diesel engines that run on regular gasoline. They are supposed to be ready by 2020.
DailyTech - Mazda Expects 30 Percent Enhanced Fuel Economy with Skyactiv 2 Engines Come 2020

 

[thecalm_7]

I've found Sam's Club fuel to run the most consistent, at least in my turbo cars. Never had problems. I dont swear by it, Im not bent for a brand, but running the same grade fuel from different stations, theirs knocked the least if at all. 4runner is more forgiving it seems, but its still new

 

[BrianSD_42]

I recently did a longer trip to a nearby city and back. I filled up that morning and then drove until the tank was down towards E. I filled up 15.5 gallons and after calculating the mileage plus the tire offset I ended up with 16.7 MPG.

I was elated. Not bad for 240,000 miles on an engine EPA rated @ 15/18 MPG on a truck with a lift kit, bumpers, sliders and 33" tires.

16.7 MPG ..... WHOOOOOOOOHOOOOO! VICTORY!!!!!!!!!

:yo:

 

[GSPRunner]

Just what we need....another MPG thread.



:nicethread:

 

[noisebeam]

Driving style is the biggest factor. 10-15% boost from a lead foot to light.

 

[Unner]

I recently did a longer trip to a nearby city and back. I filled up that morning and then drove until the tank was down towards E. I filled up 15.5 gallons and after calculating the mileage plus the tire offset I ended up with 16.7 MPG.

I was elated. Not bad for 240,000 miles on an engine EPA rated @ 15/18 MPG on a truck with a lift kit, bumpers, sliders and 33" tires.

16.7 MPG ..... WHOOOOOOOOHOOOOO! VICTORY!!!!!!!!!

:yo:

Same way I feel about mine haha.

When I drive home I always see how high I can get the MPG on my scangauge. Had it showing 18.5 MPG last night as I pulled into the driveway. Too bad that's offset by me running late every morning getting 14 MPG and then running small trips all day getting awful gas mileage... I've been averaging about 15.3 city lately, and probably 18 ish highway.

 

[Wolf_Girl]

Nope. Octane rating has nothing to do with that at all. Sounds like you're just buying into the snake oil that is the "ultra super premium patented" detergent blends they advertise.

But Kevin said higher octane makes for hotter combustion - meaning carbon gets cleaned out - unless I'm wrong - which I've noticed you guys are more than happy to point out when I am :caked:
I was simply trying to learn the why's and how's, and what if scenarios, which is why I love this forum.
I just didn't expect such deceit, and find it sad how everyone just accepts it. Literally, let the buyer beware.. lol.

 

[KidVermicious]

But Kevin said higher octane makes for hotter combustion - meaning carbon gets cleaned out - unless I'm wrong

Sorry, I guess I wasn't clear. The only thing octane in gasoline does is help prevent preignition, or engine knock. When the air/fuel mix is compressed by the closing piston, the rapid compression can cause the mix to ignite early. If that mix detonates before the piston begins to open again, Bad Things (TM) happen. So octane is added to your gasoline to ensure that the air/fuel mix ignites when the spark plug tells it to and not earlier. In higher performance motors, advanced ignition timing or higher compression levels require more octane to prevent early detonation. But the octane itself does not make a bigger boom, it doesn't clean any carbon, higher octane fuels don't do you any good at all unless your motor is designed/tuned to take advantage of them.

Lots of gas companies like to push their "premium" fuels as having more cleaning additives, but the octane itself is not one of those additives. In fact I don't think there's any fuel company that puts more of their additive package in their premium than in their regular. My understanding is that they can't due to limitations in their distribution model. But that doesn't stop them from implying that they do to get you to pay more for the premium blend. They are indeed sneaky ****ers.