Gas Mileage Question

March 7, 2022

17 minutes ago, Wiggums said:

Who bought all that oil in the first place? Oh, yes, the people who had NO INTENTION of using the oil. When I said 120, that was today's oil futures. It is laughable to say that traders reduce the swings in the market. Isn't it $120 right now? And are we in war? No, that's WTI.. WTI is $120 per barrel. Ukraine is 8,000 miles away. W..T..F.. !?!?

I'm also setting you on ignore, don't want to listen to your ignorant drivel. Good bye.

Ironic. Maybe you should listen more, and talk less. I gave you an example of what happened the last time a futures market was banned. It's not pretty.

Bamacommander · March 8, 2022

Obama proposed a ban on oil manipulation in the spring of 2012 in order to present an election deflection issue since gas prices were rising. This was done so as to provide his party with an argument to help the Dems in the midterms. It wasn’t any different when the GOP was saying they would repeal Obamacare. In fact between 2012 to 2016 they voted to repeal it on numerous occasions , but when they actually had a vote that counted , John McCain ( a Republican who had voted every time to repeal it) cast the deciding vote against it’s repeal. All this political theater is designed for the MIMS, which means the manipulation of the ignorant masses. One side blames the other side for being against there great legislative goals, and guess what, people actually buy into this nonsense and hence here we are. This is what we do know, gas prior to Biden taking office was under $2.00 a gallon, before the Ukrainian war it was up over $3.50 a gallon, and today in my state it is now over $4.00. Parties in power only want to take credit for good things and run away from the bad issues by blaming other people. So, whose to blame? I tend to look at whoever is the captain of the ship first, since they are the ones who are implementing there policy that they want to push forward. Sorry Joe, and by the way today is Monday, just in case you forgot what day of the week it was.

GN2018 · March 8, 2022

5 hours ago, 1454 said:

Weight and elevation change are major drivers too. It's not the most fun, but if you want to save 10% (~2mpg), you'll need draft behind a semi the whole way. You might get a half an mpg by taping your hood seems, and blocking off half your grille. It's stupid, I know. But that's about the best way you are going to see any actual improvements without some more major modifications. Oh, and limit the AC use. Meaning turn the A/C actually off, it will probably give you a couple of tenths on a cooler day. Those are about the easiest solutions you are going to have.

https://ecomodder.com/forum/fuel-economy-mpg-modifications.php

I agree that a 10% improvement in the gas mileage of a vehicle is unrealistic. However, that assumes improvement from the rated mileage. Basically you’re saying if the factory spec for the truck is X, it will be hard to get a 10% improvement on that. However, I’m not suggesting that. I’m looking to improve compared to my typical highway driving style which is to get in the left lane and drive 80. Generally, trying to get where I’m going as fast as road conditions and such will allow. Doing 10% better that that shouldn’t be too difficult. Basically, I need to slow down and drive smoother. The question I was asking is at what speed would I find a sweet spot. Given one of the responses above, it sounds like 62mph. I doubt I’ll be able to do that, but I’ll start there and see if I can adjust to it. On a long, uncrowded stretch of two lane highway, I can probably pull it off. Going through a metropolitan area with three lanes and people driving crazy, I’ll have to revert to my typical driving.

It will be an interesting experiment. How much gas mileage can I squeeze out of my truck without driving myself crazy. Trip is for two week later this month. I’ll definitely report back. I’m hoping I can hit something over 23mpg. That would be for the entire trip, not just something like a 50 mile stretch.

Grumpy Bear · March 8, 2022

On 3/6/2022 at 11:54 AM, GN2018 said:

Obviously driving a truck means we’re not going to get the best gas mileage but I recall a post about getting the best gas mileage out of our trucks and can’t find it now. The general conclusion was something like driving around 65mph was the sweet spot. Does anyone recall that post or what the actual conclusion was? I have a long road trip ahead. While I’m not thinking about driving 55 (ugh, shoot me now), if I can maximize my mileage and not drive too slow, I could do that. I know I’m not going to be cruising at my typical 10 to 15 over. Thankfully, I’m retired and in no hurry on this trip. All tolled, should be around 2500 miles

ETA - I have the 5.3L with the 10 speed and have averaged just over 20mpg on my last highway trips.

65 mph isn't it sir.

We've all heard that doubling the velocity increases kinetic energy by a factor of four but that equation only considers the weight of the vehicle and the difference in speed. Below is the explanation that considers the entire resistive force. Not just weight but air resistance. Even minor reductions in AIR speed will pay fuel dividends.

https://www.quora.com/When-you-double-the-horse-power-why-don’t-you-go-twice-as-fast#:~:text=Hence%2C in order to double,to reach 200 km%2Fh.

The relationship between power and speed for land vehicles is not, unfortunately, linear. That is to say, that if you double the power you do not manage to double the speed.

At any speed above somewhere around 40 km/h (25 mph) on a flat and smooth road, aerodynamic drag of the vehicle becomes the most important force that prevents the vehicle from going faster. For high speeds, let's say above 160 km/h (100 mph), aerodynamic drag of a typical car is so high that it can be considered the only force acting on a road vehicle, all the others being irrelevant compared to it (despite also all other friction forces having increased as speed has increased).

So how does this force progress? With a fairly good approximation it can be considered proportional to the square power of speed. Doubling the speed from say, 100 to 200 km/h, will result in a 2x2=4 fold increase of aerodynamic drag force.

A force applied to an object that moves against an opposing force, produces a mechanical work. In order for this work to be accomplished over a certain amount of time, a power is required. The shorter the time, the higher the power required. The relationship is linear: In order for the same quantity of mechanical work to be accomplished in half the time, power must be doubled.

Mechanical work is force times distance; power is work divided by time. But distance over time equals speed, therefore power equals force times speed. This means that, if the opposing forces remain the same at all speeds, then speed is proportional to power and indeed, doubling the power will result in doubling the speed. This is what happens for example in lifts: if you double the power of the electric motor of the lift, it will (roughly) double its speed, since the force of gravity does not change with the speed of the lift.

But the aerodynamic force that opposes the motion of a road vehicle is (approximately) proportional to the square power of the speed so, being power equal to force times speed, it must be proportional to the THIRD power of speed. Hence, in order to double the speed, the power of a land vehicle must be increased EIGHT TIMES!

For example, if a land vehicle requires 20 horsepower to travel at 100 km/h, it will require 160 HP to reach 200 km/h. If you double the horsepower of a vehicle, all the rest being equal, its speed will increase of a mere 26%: again, if 20 HP were sufficient to reach a top speed of 100 km/h, 40 HP will propel the same vehicle at the mind boggling speed of 126 km/h.

Dirk13 · March 8, 2022

8 hours ago, GN2018 said:

I agree that a 10% improvement in the gas mileage of a vehicle is unrealistic. However, that assumes improvement from the rated mileage. Basically you’re saying if the factory spec for the truck is X, it will be hard to get a 10% improvement on that. However, I’m not suggesting that. I’m looking to improve compared to my typical highway driving style which is to get in the left lane and drive 80. Generally, trying to get where I’m going as fast as road conditions and such will allow. Doing 10% better that that shouldn’t be too difficult. Basically, I need to slow down and drive smoother. The question I was asking is at what speed would I find a sweet spot. Given one of the responses above, it sounds like 62mph. I doubt I’ll be able to do that, but I’ll start there and see if I can adjust to it. On a long, uncrowded stretch of two lane highway, I can probably pull it off. Going through a metropolitan area with three lanes and people driving crazy, I’ll have to revert to my typical driving.

It will be an interesting experiment. How much gas mileage can I squeeze out of my truck without driving myself crazy. Trip is for two week later this month. I’ll definitely report back. I’m hoping I can hit something over 23mpg. That would be for the entire trip, not just something like a 50 mile stretch.

I have a 3.0 Duramax so not sure how much the below will relate to the 5.3 but it’s certainly possible, especially if you’re currently driving like that.

I drive a 175 mile round trip for work 2-3 times a week. Driving however I felt like (included 80+mph in early mornings, “spirited” acceleration at times) got me an overall average of somewhere around 23.5 on that trip. I did it three days in a row last week and did all I could to get the best MPG. Driving at 60 on 55mph roads and 66-68 on 65 mph roads, the absolute minimum throttle input for the situation, and actually using auto start/stop. I ended up at 28.0 for the three days.

March 8, 2022

8 hours ago, GN2018 said:

I agree that a 10% improvement in the gas mileage of a vehicle is unrealistic. However, that assumes improvement from the rated mileage. Basically you’re saying if the factory spec for the truck is X, it will be hard to get a 10% improvement on that. However, I’m not suggesting that. I’m looking to improve compared to my typical highway driving style which is to get in the left lane and drive 80. Generally, trying to get where I’m going as fast as road conditions and such will allow. Doing 10% better that that shouldn’t be too difficult. Basically, I need to slow down and drive smoother. The question I was asking is at what speed would I find a sweet spot. Given one of the responses above, it sounds like 62mph. I doubt I’ll be able to do that, but I’ll start there and see if I can adjust to it. On a long, uncrowded stretch of two lane highway, I can probably pull it off. Going through a metropolitan area with three lanes and people driving crazy, I’ll have to revert to my typical driving.

It will be an interesting experiment. How much gas mileage can I squeeze out of my truck without driving myself crazy. Trip is for two week later this month. I’ll definitely report back. I’m hoping I can hit something over 23mpg. That would be for the entire trip, not just something like a 50 mile stretch.

Definitely, if you can, try to get behind any car. Even small cars reduce the effective frontal area because of the air pocket they have created. When I was driving to NJ every week last year, I got 22.4 over multiple tanks by using semis whenever I could with my 6.2. This was 1000 miles round trip weekly. It takes a very dedicated right foot. I honestly don't do this to save money, I do/did it to keep my mind active on long trips.

I have found 58-62 seems to be the best speed for highest milage. That's with my 6.2/10sp. I can't speak to others, and this is anedotal from me watching the instant dic. I've seen 50 mile stretches near the 30's in thst range with maintaining a good distance to still take advantage of cars in front of me.

Edited March 8, 2022 by 1454

March 8, 2022

15 minutes ago, Grumpy Bear said:

65 mph isn't it sir.

We've all heard that doubling the velocity increases kinetic energy by a factor of four but that equation only considers the weight of the vehicle and the difference in speed. Below is the explanation that considers the entire resistive force. Not just weight but air resistance. Even minor reductions in AIR speed will pay fuel dividends.

https://www.quora.com/When-you-double-the-horse-power-why-don’t-you-go-twice-as-fast#:~:text=Hence%2C in order to double,to reach 200 km%2Fh.

The relationship between power and speed for land vehicles is not, unfortunately, linear. That is to say, that if you double the power you do not manage to double the speed.

At any speed above somewhere around 40 km/h (25 mph) on a flat and smooth road, aerodynamic drag of the vehicle becomes the most important force that prevents the vehicle from going faster. For high speeds, let's say above 160 km/h (100 mph), aerodynamic drag of a typical car is so high that it can be considered the only force acting on a road vehicle, all the others being irrelevant compared to it (despite also all other friction forces having increased as speed has increased).

So how does this force progress? With a fairly good approximation it can be considered proportional to the square power of speed. Doubling the speed from say, 100 to 200 km/h, will result in a 2x2=4 fold increase of aerodynamic drag force.

A force applied to an object that moves against an opposing force, produces a mechanical work. In order for this work to be accomplished over a certain amount of time, a power is required. The shorter the time, the higher the power required. The relationship is linear: In order for the same quantity of mechanical work to be accomplished in half the time, power must be doubled.

Mechanical work is force times distance; power is work divided by time. But distance over time equals speed, therefore power equals force times speed. This means that, if the opposing forces remain the same at all speeds, then speed is proportional to power and indeed, doubling the power will result in doubling the speed. This is what happens for example in lifts: if you double the power of the electric motor of the lift, it will (roughly) double its speed, since the force of gravity does not change with the speed of the lift.

But the aerodynamic force that opposes the motion of a road vehicle is (approximately) proportional to the square power of the speed so, being power equal to force times speed, it must be proportional to the THIRD power of speed. Hence, in order to double the speed, the power of a land vehicle must be increased EIGHT TIMES!

For example, if a land vehicle requires 20 horsepower to travel at 100 km/h, it will require 160 HP to reach 200 km/h. If you double the horsepower of a vehicle, all the rest being equal, its speed will increase of a mere 26%: again, if 20 HP were sufficient to reach a top speed of 100 km/h, 40 HP will propel the same vehicle at the mind boggling speed of 126 km/h.

That's overly simplistic. Yes, in general terms, ignoring mechanical advantages, this is correct. However, in real world, I've experienced a decrease in mileage below 50 because it seems the truck hold a higher gear. I've personally had the best results between 55-65. Especially since nobody drives 30, you also gain the advantages of using other cars to draft behind.

diyer2 · March 8, 2022

This doesn't make sense. Why did you buy a truck if gas mileage is important.

Dirk13 · March 8, 2022

22 minutes ago, diyer2 said:

This doesn't make sense. Why did you buy a truck if gas mileage is important.

Useful post, thanks for really bringing a lot to the discussion.

It’s not about getting “good” mpg or it being important, just maximizing what’s possible. Who buys a truck for fuel economy? No one, you don’t need to point that out. Trucks are driven for other reasons but that doesn’t mean you can’t try to get the best fuel economy possible while driving that truck, especially when prices are rising.

diyer2 · March 8, 2022

I guess the difference is I'm not concerned about mileage.

Fixed Edited

Edited March 8, 2022 by diyer2

Dirk13 · March 8, 2022

9 minutes ago, diyer2 said:

I guess the difference is I don't worry about mileage.

And if I didn’t drive many miles I wouldn’t either. With fuel costs at $5.29, the 4.5 mpg difference I get between driving how I want and driving to maximize economy means a $75 a month difference. That’s not insignificant and would be stupid not to take advantage of.

March 8, 2022

13 minutes ago, diyer2 said:

I guess the difference is I don't worry about mileage.

Who said anything about worrying about it? I do it as a game for mental stimulation while driving long trips. I can't speak for OP. If I cared that much about it, I'd have bought a prius.

GN2018 · March 8, 2022

38 minutes ago, 1454 said:

Who said anything about worrying about it? I do it as a game for mental stimulation while driving long trips. I can't speak for OP. If I cared that much about it, I'd have bought a prius.

That pretty much sums it up. Also, if I can save $50 to $100 with virtually no effort, I’m in for that. I’m retired, I have plenty of time.

Most of the time I drive near home in suburbia. Not much I’m willing to do different on those roads - typically 40 to 45mph speed limits. And no, I didn’t expect a truck to get good gas mileage, but I didn’t think gas would get this high this quick. I don’t drive enough to care, but it still hurts a bit going over $80 on a fill up. Still, I love my truck and have no plans to get rid of it anytime soon.

KARNUT · March 8, 2022

I didn’t think I’d ever be in the market for another truck. I only drive mine in town. If gas levels out high there’re going to flood the market. Of course GM and ford will be caught again with its pants down getting rid of cars. Ford is a little better off with the maverick. And I may be in the market for a reduced gas guzzler.

It's Tim · March 8, 2022

2 hours ago, 1454 said:

*

Distracted driving is the act of driving while engaging in other activities which distract the driver's attention away from the road. Distractions are shown to compromise the safety of the driver, passengers, pedestrians, and people in other vehicles.