mpg gauge reliability

[Collin]

Update:

I drove on wet roads and the mpg was 13. It seems the big boost was caused by dry roads making for less drag than driving a wet road.

 

[Deviate]

I calculated mine by hand today for the first time after changing my spark plugs. The overhead had me at 14.2 MPG. Calculating it straight off of the miles traveled divided by the gallons of gas, it came out to 13.7 MPG. But, I have larger than stock tires now and I never have adjusted for that in the computer since I don't have a tuner or anything. So adjusting for the larger tires, I got 14.4.

So funny enough, the overhead is pretty close for my actual MPG.

 

[Collin]

I calculated mine by hand today for the first time after changing my spark plugs. The overhead had me at 14.2 MPG. Calculating it straight off of the miles traveled divided by the gallons of gas, it came out to 13.7 MPG. But, I have larger than stock tires now and I never have adjusted for that in the computer since I don't have a tuner or anything. So adjusting for the larger tires, I got 14.4.

So funny enough, the overhead is pretty close for my actual MPG.

How much highway is that?

I'm getting about the same mpg with my humming tires.

The weirdest thing is how mpg can vary with weather. Warm and dry gives me 2 mpg better than cold and rainy.

 

[Stangshcky12]

Left school and the lie o meter said 110 miles to empty (conveniently its 110 miles exactly from school to my house)
After 60 miles I stopped at a gas station for food (and fuel) and the lie o meter said 34 miles to empty
32% error
I only put 4.79 gallons in to get me home since we have a fuel tank, which took the lie I meter up to 120 miles to empty
All this is rough math but going off of the overhead, i used 4.39 gallons to go 60 miles/13.67mpg and it's all highway
The meter has been averaging about 19mpg on trips back and forth to school and averaged 18.1 over the 500+ miles on this past tank of fuel of mixed highway and city
So te theoretical nog from today is about 28% off of what it says I'm averaging

That's just way to much for me to trust
I wish I had a Volune meter on our tank do I could get real numbers

 

[Collin]

Update:

For a short trip, I've been able to average 15.4 mpg in flat city/country driving.

I've noticed the mpg doesn't seem to vary very much between going say 35 mph and 45 on flat roads--and actually, if I go 45 I can coast a lot further to stop signs or coast to slow down around a turn. If I won't be stopping any time soon, it's more efficient to drive fast.

Also, it's much better to take side roads without traffic or lights. You can go any speed you want and coasting to stops or slowing for turns without using the breaks is where you'll find a lot of your gains.

It pays to count how many stop signs you'll have to deal with. Every time you stop your mpg goes wayyyyy down. It's worth it to drive a different route to avoid even 1 of those stupid things.

Going 50 mph down a flat stretch of road can yield 17 mpg, but if you have to go down the same road and I have to accelerate from a dead stop, I'll only average 13.5.

 

[Deviate]

My mpg is based on probably 80% highway. And by highway I mean I-95 doing between 70 and 75mph. If I take some of the back roads where the speed limit is 55 I can get a bit better. But it takes too long to get to work and I don't have the time usually.

 

[Collin]

My mpg is based on probably 80% highway. And by highway I mean I-95 doing between 70 and 75mph. If I take some of the back roads where the speed limit is 55 I can get a bit better. But it takes too long to get to work and I don't have the time usually.

I hope the drive isn't very long, or you're going to be paying lotssss in gas!

 

[swamp_life hemi 05]

Wats mods have you done to your hemi?? When I had my stock wheels and tires with a tuner, exhaust and k&n filter I was averaging 19-20mpg going 55-60mph on long trips.

Sent from my ADR6350

 

[Deviate]

I hope the drive isn't very long, or you're going to be paying lotssss in gas!

50 miles round trip 4-5 days a week. Depending on how often I decide to work from home. Hence one reason I'm buying a motorcycle now.

 

[Collin]

Still trying to get better mpg!

I hit a peak of 16 mpg average on a trip recently. that was cool, but the overall average was still only 14.5 by the time I got home. Damn hills and stop signs.

I wonder how much improvement I would get from changing the transmission fluid to synthetic. problem is I don't feel I'm competent enough to do it.

 

[SmokedRam]

Still trying to get better mpg!

I hit a peak of 16 mpg average on a trip recently. that was cool, but the overall average was still only 14.5 by the time I got home. Damn hills and stop signs.

I wonder how much improvement I would get from changing the transmission fluid to synthetic. problem is I don't feel I'm competent enough to do it.

the trans fluid you currently have in your trans (ATF+4) is a synthetic trans fluid.

 

[Collin]

the trans fluid you currently have in your trans (ATF+4) is a synthetic trans fluid.

Awesome. what about diff fluid?

 

[Collin]

Update:

hit 14.8 on the same route. Getting 3 more mpg than I was getting at first seems worth the effort.

if it wasn't for the hills, I think I'd be averaging close to 16 mpg instead of 15.

 

[07' Hemi]

Mine was reading 11.3-13.8. So I did the math and Im averaging around 20-22 depending on what pulls up next to me at a light.

 

[drkmtr]

I thought I was getting bad MPG, but after seeing some of ya'lls claims, I feel good about my 17 average to and from work. Granted my computer says my average is 15.4, but it gains .1 about every 2-3 tank fulls. You have to remember, the odometer reset just resets the miles, the computer (to my understanding) keeps a running MPG average over the life of the vehicle, if this is true, you will never see the exact same MPG as what you get on paper for that single tank of fuel.

 

[Collin]

Mine was reading 11.3-13.8. So I did the math and Im averaging around 20-22 depending on what pulls up next to me at a light.

20 mpg? That seems way off. Going down the highway at a steady speed you might be getting 20 mpg, but not as an average.

 

[Collin]

I thought I was getting bad MPG, but after seeing some of ya'lls claims, I feel good about my 17 average to and from work. Granted my computer says my average is 15.4, but it gains .1 about every 2-3 tank fulls. You have to remember, the odometer reset just resets the miles, the computer (to my understanding) keeps a running MPG average over the life of the vehicle, if this is true, you will never see the exact same MPG as what you get on paper for that single tank of fuel.

17 is very good if it's city.

I've just been able to hit 16 mpg city. That's when i accelerated extra slow and only touched the brake for stop signs.

To put it into perspective, some of the new chargers only get around 18 mpg.

 

[Collin]

Getting around 15 mpg lately...with a peak of 17.5 city. Not bad for a truck.

 

[LoneTex]

MY 3.7 is horrible on gas. I always step in it and wind out gears so that might not help haha. It is pretty quick for a v6 I must say!

 

[drkmtr]

I have a friend at work that has the same basic truck as mine but with the V6 and he gets horrible mileage. He drives the same route I do and he is lucky when he gets 15. I drive about 15 miles one way to work, 2 miles at 70, 8 at 50 and the rest is stop and go at about 30. I drive like a grandpa getting up to speed, so that helps a ton. I try to use the cruise as much as possible as well. I even have a bat IAC and TPS ( I really need to replace them, but just don't have the $), as long as I'm above 1k RPM she runs fine.