Fuel Economy emphasis

[FLG8R]

Seems we have pretty much peaked in our push for fuel economy numbers. We shave 200 to 300lbs off a truck to gain 1 mpg and its not working. So we modify the transmission shift points and compromise driveability. And when you hear about some owners issues with their A/C output you wonder if the compressors have not been downsized for less pull on the engine. Yet we keep making trucks bigger in a peeing contest with our competitors. Something has to give. I want to own a truck not a school bus.

 

[Cattail cruncher]

My AC is good , just drove from AZ to WA stoped in LA for 2 days 4 mountan passes 19.8 mpg. It was 113° in AZ no problem staying cool in the truck, heck you could cook an egg on the hood, whats not to like. My 2003 ram gets 9 mpg so the same trip would double in price. PS bought the 2019 RAM in AZ.

 

[Whynot]

MPG is not a linear scale (which is its biggest weakness and why L/km is popular overseas and not km/L). Going from 17 to 18 mpg, for example, is actually a slightly better improvement than going from 30 mpg to 33 mpg. So yeah, getting only 1 more mpg may not seem impressive, but it is actually a very good improvement when your fuel economy is crap.

 

[rvsixer]

MPG is not a linear scale (which is its biggest weakness and why L/km is popular overseas and not km/L). Going from 17 to 18 mpg, for example, is actually a slightly better improvement than going from 30 mpg to 33 mpg.

Not sure I follow.

MPG percentage increase (% increase = Increase ÷ Original Number × 100):
17mpg to 18mpg => (18-17)/17 = 5.9% increase
30mpg to 33mpg => (33-30)/30 = 10.0 % increase (largest improvement in mpg)

Overseas L/100km is used, L/100km percentage decrease (% Decrease = Decrease ÷ Original Number × 100):
17mpg to 18mpg => 13.84 L/100km to 13.07 L/100km => (13.84-13.07)/13.84 = 5.6% decrease
30mpg to 33mpg => 7.84 L/100km to 7.13 L/100km => (7.84-7.13)/7.84 = 9.1% decrease (largest improvement in L/100km)

In both measures, I see the second option showing a greater consumption improvement than the first, and both are linear (since in both, both the distance and volume measures are linear).

Counterpoint/math please.

 

[FLG8R]

Not sure I follow.

MPG percentage increase (% increase = Increase ÷ Original Number × 100):
17mpg to 18mpg => (18-17)/17 = 5.9% increase
30mpg to 33mpg => (33-30)/30 = 10.0 % increase (largest improvement in mpg)

Overseas L/100km is used, L/100km percentage decrease (% Decrease = Decrease ÷ Original Number × 100):
17mpg to 18mpg => 13.84 L/100km to 13.07 L/100km => (13.84-13.07)/13.84 = 5.6% decrease
30mpg to 33mpg => 7.84 L/100km to 7.13 L/100km => (7.84-7.13)/7.84 = 9.1% decrease (largest improvement in L/100km)

In both measures, I see the second option showing a greater consumption improvement than the first, and both are linear (since in both, both the distance and volume measures are linear).

Counterpoint/math please.

WOW! I know I do a pretty good job of stirring the pot and stoking the fire with my posts. But in all honesty this was not intended to be one of them. My intent was just to say that we seem to do these things just so that we can justify making bigger trucks. This thought came to mind when I recently looked at an older model full size Chevy sitting next to one of their so called mid sized Colorados. I could visually see no difference in size.

 

[Whynot]

Not sure I follow.

MPG percentage increase (% increase = Increase ÷ Original Number × 100):
17mpg to 18mpg => (18-17)/17 = 5.9% increase
30mpg to 33mpg => (33-30)/30 = 10.0 % increase (largest improvement in mpg)

Overseas L/100km is used, L/100km percentage decrease (% Decrease = Decrease ÷ Original Number × 100):
17mpg to 18mpg => 13.84 L/100km to 13.07 L/100km => (13.84-13.07)/13.84 = 5.6% decrease
30mpg to 33mpg => 7.84 L/100km to 7.13 L/100km => (7.84-7.13)/7.84 = 9.1% decrease (largest improvement in L/100km)

In both measures, I see the second option showing a greater consumption improvement than the first, and both are linear (since in both, both the distance and volume measures are linear).

Counterpoint/math please.

You are looking at the wrong metric. What actually matters is gallons of gas used (and ultimately price we are paying for that) not “mpg”. If you drive 10,000 miles a year at 17 mpg you use 588 gallons (all numbers rounded) of gas. At 18 mpg you use 555 gallons... a 33 gallon improvement. At 30 mpg you use 333 gallons, at 33mpg you use 303 gallons...saving 30 gallons.

The price of fuel is fixed, it is not asked on usage. You don’t pay more for a gallon of fuel if you have already used 500 gallons versus if you have already used 300 gallons. You are getting the same annual fuel cost benefit going from 17->18 mpg as going from 30->33 mpg.

This is why the pace of mileage improvements slows down significantly after 40mpg. Getting that extra efficiency out of it while still being cost effective for consumer is hard, especially when 1mpg improvement starts to only equal a few gallons of gas a year.

 

[rvsixer]

You are looking at the wrong metric. What actually matters is gallons of gas used (and ultimately price we are paying for that) not “mpg”. If you drive 10,000 miles a year at 17 mpg you use 588 gallons (all numbers rounded) of gas. At 18 mpg you use 555 gallons... a 33 gallon improvement. At 30 mpg you use 333 gallons, at 33mpg you use 303 gallons...saving 30 gallons.

Most interesting way to look at it, thanks for the viewpoint.

 

[alacombe]

You are looking at the wrong metric. What actually matters is gallons of gas used (and ultimately price we are paying for that) not “mpg”. If you drive 10,000 miles a year at 17 mpg you use 588 gallons (all numbers rounded) of gas. At 18 mpg you use 555 gallons... a 33 gallon improvement. At 30 mpg you use 333 gallons, at 33mpg you use 303 gallons...saving 30 gallons.

The price of fuel is fixed, it is not asked on usage. You don’t pay more for a gallon of fuel if you have already used 500 gallons versus if you have already used 300 gallons. You are getting the same annual fuel cost benefit going from 17->18 mpg as going from 30->33 mpg.

This is why the pace of mileage improvements slows down significantly after 40mpg. Getting that extra efficiency out of it while still being cost effective for consumer is hard, especially when 1mpg improvement starts to only equal a few gallons of gas a year.

So how long will it take to pay off the $800 E-torque add on at 1mpg gain? lol

 

[rvsixer]

So how long will it take to pay off the $800 E-torque add on at 1mpg gain? lol

Depends on how/where you drive. If its mostly open highway my guess is a rather long time for payoff. In the city, the gain is more than 1mpg (probably closer to 2mpg won't know till we have a few reports from the road), and the system comes with stop/start capability as well (I hate looking at my average mpg tanking every time my current truck idles in stop'n'go traffic).

Since I also pull a trailer, I am looking forward to having 130 lb ft of torque at zero rpm before the Hemi spools up and takes over .

 

[cjgerson]

Well assume the following

1. you pay invoice price for eTorque that is $727
2. Drive 12,000 miles a year
3. Fuel costs $2.75 a gallon
4. Average fuel economy is 19 vs 17 mpg

12000 miles @ 17 mpg = 706 gallons
12000 miles @ 19 mpg = 632 gallons
So savings on 74 gallons @ $2.75 = $2o4 per year
$727/$204 = 3.5 years

 

[Kramersp]

It should pay off quick with increased driveability, take off MPG, towing MPG, ect. But like he said, if all you're doing is mostly unloaded highway driving, it'll be a while.

 

[rvsixer]

Fuel costs $2.75 a gallon

I wished gas was only $2.75/gal here on the left coast ! Paying $3.75/gal here for the car, $3.80/gal diesel for the truck. E-torque should pay for itself quickly, as my daily commute is 50% hwy/ 50% stop n' go.

 

[Cattail cruncher]

$2.75 a gallon at that price I am doing a dance at the pump we are $3.65.

 

[VaderRebel]

The fuel conversation always confuses me a bit... I ordered a bad-*** Rebel with 400hp... not a Smart car. I don't think about gas until the truck dings and says it's thirsty. Gotta spend your money somehow!

I also burn tires in my backyard, viva-la-global-warming! Just in case any of the tree huggers were wondering.

 

[SpeedyV]

When I was truck shopping, I ran some numbers on fuel economy, just for fun (I only put 6-8K miles on my truck per year). I've updated them below based on the new eTorque numbers and 2019 GMC rating:

Contestants

2018 Ford F-150
3.5L V6 EcoBoost engine (375 HP, 470 lb-ft, 17/23/19 mpg): "Your vehicle is designed to run on regular fuel with an octane rating of 87 or higher. For best overall performance, premium fuel with an octane rating of 91 or higher is recommended."

2019 Ram 1500
5.7L V8 Hemi eTorque engine (395 HP, 410 lb-ft, 17/22/19 mpg): "89 Octane Recommended - 87 Octane Acceptable, 0-15% Ethanol (Do not use E-85)."

2019 GMC Sierra 1500
6.2L V8 engine (420 HP, 460 lb-ft, 16/20/17 mpg): "Use premium 93 octane unleaded gasoline in your vehicle. Unleaded gasoline with an octane rating as low as 87 may be used, but it will reduce performance and fuel economy."

2003 GMC Sierra 1500HD (just for fun)
6.0L V8 engine (OE rated at 300 HP, 360 lb-ft, 10/11/10 mpg): Truck is tuned for 89+ and typically run 93 octane, with real-world economy of 11-12 city / 12-14 highway.

Results

Disclaimer: At just 7,500 miles/year, I'm not worried about fuel economy. So the differences shown below are minimal (using combined efficiency ratings). But let's compare anyway!

• First, my existing truck (2003 GMC Sierra 1500HD) easily consumes the most gas. At an average of roughly 12 mpg, I'm using 625 gallons per year. At $2.99/gal (93 octane), this translates to an annual fuel cost of $1,869. This sets our baseline.
• The new 2019 GMC Sierra consumes 441 gallons/year in the same scenario, saving me 184 gallons ($550). That's a good start.
• The 2018 Ford F-150 and 2019 Ram 1500 both consume 395 gallons/year, saving me an additional 46 gallons ($138) over the GMC. Better.

The math gets a bit more sophisticated if you consider recommended octane levels:

• The 2019 Ram 1500 finishes first overall, with annual fuel consumption costing $1,082/year at 89 octane (19 mpg, $2.74/gal).
• The 2018 Ford F-150 takes second, at $1,180/year, despite the same combined economy rating as the Ram, at 91 octane (19 mpg, $2.99/gal).
• The 2019 GMC Sierra (6.2L) finishes third, at $1,319/year, as this engine recommends 93 octane and consumes more fuel (17 mpg, $2.99/gal).

For me, there's little difference (less than $250) in annual fuel costs between these trucks. All of them save money over my current truck. But I'm not, for example, expecting to recover the cost of the eTorque option from fuel savings (even though it will do so in 5.3 years, per the post by @cjgerson above but using $2.99/gal). More importantly, these numbers might be extrapolated to show a more significant cost savings for those of you that put 20-30K/year or more on your trucks.

 

[2019REBEL]

I wish gas was that cheap over $5 a gallon here in Canada

 

[alacombe]

I wish gas was that cheap over $5 a gallon here in Canada

$2.89 by me

 

[Jared B]

I wish gas was that cheap over $5 a gallon here in Canada

You're telling me. $1.60 a litre x 3.78544 to convert to US gallons = $6.056 a gallon.

 

[mikemcfarland]

You're telling me. $1.60 a litre x 3.78544 to convert to US gallons = $6.056 a gallon.

looks like us canadians will be looking for a smart car WITH ramboxes very soon.

 

[Jared B]

looks like us canadians will be looking for a smart car WITH ramboxes very soon.

Lol, yeah thats the whole reason I bought a commuter car a few months ago.