Interesting notes on fuel economy

[Neurobit]

I have a 5 mile commute, so almost all of my driving is the Hemi getting up to (but not at) full operating temperature. If I can eeek 12MPG out of a tank I had a good run.

Yep, that confirms what I see as well when I drive other places within a 5-10 mile radius.

 

[Drewster]

That's just the stop light by my office. The rest of the way is easy going.
I'd love to walk or ride a bike, but with the Houston humidity that's not feasible (I'd be dripping wet by the time I get to work). Yeah, it's that muggy down here.

I'm well aware - I'm also in Texas

 

[realralfy]

I have noticed increased mpg when using 100% gas (no ethanol)...

My average with the E10 is 13.25 mpg no matter what octane, with the ethanol free gas, I'm getting 14.75 mpg average....

 

[RAM Patriot]

I have noticed increased mpg when using 100% gas (no ethanol)...

My average with the E10 is 13.25 mpg no matter what octane, with the ethanol free gas, I'm getting 14.75 mpg average....

I average 1 - 3 MPG difference when I stay away from ethanol.

It gets better the more I run it. Must take several tanks to run all of the ethanol out since I fill up when I'm at 1/4 tank.

 

[realralfy]

I average 1 - 3 MPG difference when I stay away from ethanol.

It gets better the more I run it. Must take several tanks to run all of the ethanol out since I fill up when I'm at 1/4 tank.

If it gets 15% better mileage on 100% gas, then it's worth $.35 to $.45 per gallon more....I'm going to stick with this 100% gas for a while. Seems like a good idea....

 

[theblet]

I commute about 30min. Above 55 it’s hard to get mds to activate at all. Also, if there’s any kind of wind, it almost never activates.

 

[bpwj76]

When you fill up you take the miles driven then divide by the gallons pumped into the tank. Easy and accurate.

The computer has to use all the parameters to calculate what it thinks you are getting and then keeps a tally until you reset it. For a live calculation it's pretty close but is usually a little higher than what the actual is.

I always calculate my mileage that way. I even keep a spreadsheet, becuase I'm a nerd. I guess my point was that the Fuelly average (14.6 mpg) in my signature is accurate over the entire time I've had the truck. Total miles driven divided by total gallons pumped. Well, Fuelly is showing the average over the last 10 fillups (14.6) for some reason. Can't figure out how to show the average over all fillups (14.9).

The truck's computer thinks it's 18.9 mpg for some reason.

And you are correct, the trip computer average is always at least .5 mpg more optimistic at each fillup.

 

[brian42]

I commute about 30min. Above 55 it’s hard to get mds to activate at all. Also, if there’s any kind of wind, it almost never activates.

There's a lot of variables that can affect that.

I have MDS kick in a lot on the freeway and I set my cruise control at 70 MPH (69 MPH actual). My dad has a 2020 Limited with eTorque and MDS seldom kicks in on the freeway.

His truck is also Delmonico Red. Maybe that has something to do with it.

 

[Buz]

There's a lot of variables that can affect that.

I have MDS kick in a lot on the freeway and I set my cruise control at 70 MPH (69 MPH actual). My dad has a 2020 Limited with eTorque and MDS seldom kicks in on the freeway.

His truck is also Delmonico Red. Maybe that has something to do with it.

A few weeks ago I had MDS kick in on the interstate at 78 MPH. It shocked me at first until I realized the wind was blowing 25-30mph that day and it was a perfect tailwind when it happened.
In your case do both of your trucks have the same rear end gear ratio? Maybe one is 3.92 and one is 3.21?

 

[brian42]

Both of our trucks are very similar until you get to the luxury level. Both are CCSB 4x4 ORG trucks with 3.21 rears.

He does have eTorque, RAM boxes, and a lot of leather that mine does not have.

 

[Patamaran]

I commute about 30min. Above 55 it’s hard to get mds to activate at all. Also, if there’s any kind of wind, it almost never activates.

Mine normally kicks in at those speeds, even a bit above that using cruise control. Without using cruise, It doesnt turn on, my foot being an extra variable.

 

[Rickyrocket]

I just did an 1831 mile trip,RI to Myrtle Beach, average 22.3 mpg with the Hemi ,4x4,3.21s,and 1500 lbs of people & gear, usually running 5-10 mph over the limit.

 

[IvoryHemi]

E-Torque really really helps with start/ stop commutes like that. When I got a new job that was much closer, my old (non MDS, non e-torque) Hemi was getting 12 mpg with even my most gentle hypermiling. The new Ram gets about 17.5 mpg on the exact same commute.

eTorque is not going to give you +5.5 mpg, it’s more like <1mpg

You can attribute the improved fuel economy from the last non-MDS 5.7 back in 2005 to the vastly improved transmission (8HP75 vs 545RFE) and the twice redesigned 5.7 Hemi (‘06 and again in ‘09).

 

[theblet]

Yes it’s more difficult to initiate mds without the cruise for sure

 

[Mountain Whiskey]

Mine should be here in a few weeks. I figure that because I was told "by the end of the month" Interested to see what I get. Just sold off my 2020 Rubicon today. 3.6l with 4.10 gears, less than half the weight of a truck and I was getting 16 to 17 mpg. A jeep is less aerodynamic than a cow though so there is that.

 

[Drewster]

eTorque is not going to give you +5.5 mpg, it’s more like <1mpg

You can attribute the improved fuel economy from the last non-MDS 5.7 back in 2005 to the vastly improved transmission (8HP75 vs 545RFE) and the twice redesigned 5.7 Hemi (‘06 and again in ‘09).

Per the EPA, it's 2 MPG bump in the city so I'm not sure where you're pulling that number from... From FCA's own press releases, and it's repeated in 3rd party articles, the 'ol port injected Hemi uses 1.7 ounces of fuel during an average 90 second stop. Since port injection is pretty limited on injector duty cycle, I wouldn't be surprised if 8 cylinders displacing 5.7L uses pretty much the same amount of fuel in any generation while you're sitting at idle. On my 5 mile drive to work, I go through about 10 light cycles in rush hour when lights are backed up, so that's over a tenth of a gallon in just one direction, or ~0.25 gallons in one day.

Let's say you normally drive in a stop and go commute like me and you get 12mpg, that means you're burning 0.83 gallons a day. What if you didn't burn those 0.25 gallons and instead only used 0.58 during that day? Well, that means you'd be getting about 17.2 mpg. Sooo yeah, the more you drive efficiently, let eTorque brake and charge up rather than speeding up to the red light, etc. the more it's going to matter if you sit and idle a lot.

Naturally if you don't have a stop and go commute it matters much less, but for the guy I was replying to it might actually help quite a bit.

 

[IvoryHemi]

EPA mpg and real world mpg rarely jive

 

[Drewster]

EPA mpg and real world mpg rarely jive

It all comes down to how you drive. I have eTorque, and I'm saying it helps a lot if you have a stop and go commute with lots of what would be idling (as long as you don't drive like a moron). The numbers also reflect that. Do you even have an eTorque engine, or are you just confusing your opinions with facts?

 

[theblet]

EPA is done in a lab, not on the road. Also on 89 octane

 

[Drewster]

EPA is done in a lab, not on the road. Also on 89 octane

Look, real world, I get 17mpg on my stop and go commute running TopTier 89 Octane. If I didn't have eTorque and let my V8 idle at every single stop on my commute, there's no way I could get that MPG, period.

My point is that a "lab" is saying eTorque is worth 2MPG, so where is he getting this "eTorque gives you more like <1 mpg"? ..The answer is that he's making an assumption and doesn't actually have any data of his own.