Gas Mileage Question

TNTSierra · March 9, 2022

Never mind. I just saw what you highlighted. My damn iPhone didn’t show it right away. Too funny!!! Ya Im not a Tequila fan.

we can survive without Tequila. Most of the US can’t survive without gasoline.

Dirk13 · March 9, 2022

14 minutes ago, TNTSilverado said:

Explain

edit:
i take it back

Edited March 9, 2022 by Dirk13

Dirk13 · March 9, 2022

1 minute ago, TNTSilverado said:

Never mind. I just saw what you highlighted. My damn iPhone didn’t show it right away. Too funny!!! Ya Im not a Tequila fan.

we can survive without Tequila. Most of the US can’t survive without gasoline.

Yeah this mobile version of the forum is trash.

I can certainly survive without tequila.

TNTSierra · March 9, 2022

1 minute ago, John F. said:

Damn dude calm down. I think you took it out of context. I was making a joke about the Tequila shortage. I said I was lucky about getting a fuel card. But I drive MY truck for my job. You don't know anything about me or my job. I put mileage on MY truck to make the company I work for ALOT of money. I'm good at what o do and get paid accordingly. I'm sorry McDonald's doesn't pay for your gas. Enjoy your Bud Light and chill out.

First off. It was a very selfish statement. 2nd I could care less what you make for money. Congrats. I have 2 masters degrees (one on the human brain) and I make very good money as well, but I’m not on here stating I don’t care about gas prices.
You sounded quite ignorant! Now go have your Tequila and watch The View. Sounds right up your alley.

Good day.

Grumpy Bear · March 9, 2022

13 hours ago, 1454 said:

That's overly simplistic. Yes, in general terms, ignoring mechanical advantages, this is correct.

Sir Isaac Newton will be pleased to learn you find his explanations of the laws of motion correct....

in general terms.

March 9, 2022

15 hours ago, Grumpy Bear said:

Sir Isaac Newton will be pleased to learn you find his explanations of the laws of motion correct....

in general terms.

You completely missed the point. The point is that the motor produces 100 hp as low as 1200 RPM, and therefore the lower the RPMs (mechanical advantage) means that driving the *fastest* you can at the lowest RPM results in the highest MPG. You neglected that in your overly simplistic statement. As you seemed to suggest that driving 15 mph would result in better gas mileage than say, 55, with the right gearing. If you can drive 60 and overcome drag @ 900RPM you are going to have peak efficiency as you are already losing most of the energy as heat. Geez. This is why you are one of the most insufferable people on here.

Edited March 9, 2022 by 1454

Wiggums · March 9, 2022

Been reading the thread...

Having twice the power doesn't mean twice the speed. Aerodynamics, gearing, terrain, all play a role. Aerodynamics is largely responsible since going twice the speed means 10x the resistance. Even if the truck's RPM is 2,000 at both 60 mph and 80 mph, it is still working much harder at 80 mph due to aerodynamics being whatever-fold compared to 60 mph.

I'm no scientist so I'll just stick with my Don Julio 1942.

Grumpy Bear · March 9, 2022

5 hours ago, 1454 said:

You completely missed the point. The point is that the motor produces 100 hp as low as 1200 RPM, and therefore the lower the RPMs (mechanical advantage) means that driving the *fastest* you can at the lowest RPM results in the highest MPG. You neglected that in your overly simplistic statement. As you seemed to suggest that driving 15 mph would result in better gas mileage than say, 55, with the right gearing. If you can drive 60 and overcome drag @ 900RPM you are going to have peak efficiency as you are already losing most of the energy as heat. Geez. This is why you are one of the most insufferable people on here.

Nope. Missed nothing. Your assumption "As you seem to suggest" is in error. I suggested nothing of the sort. Did you read the article? There was a lower limit at which aero drag is no longer the primary resistance. It gave that number in meters/second and MPH.

The most fuel efficient speed is the one that allows the motor to operate MAINLY in the highest gear AND in the most fuel efficient area of the fuel map. Normally in modern motors that is between one 1K and 1.5K. For most BOX like automobiles this happens to be between 43 and 53 mph. And that, as I said before is AIR speed, not road speed. 43 mph in my personal truck is minimum speed the 6 speed with a 31 inch tire and a 3.23 gear will shift up to high.

I don't argue physics anymore than I would argue the sum of 2 added to 2. Discuss yes, argue no. Have a nice day.

March 10, 2022

On 3/9/2022 at 1:13 PM, Wiggums said:

Been reading the thread...

Having twice the power doesn't mean twice the speed. Aerodynamics, gearing, terrain, all play a role. Aerodynamics is largely responsible since going twice the speed means 10x the resistance. Even if the truck's RPM is 2,000 at both 60 mph and 80 mph, it is still working much harder at 80 mph due to aerodynamics being whatever-fold compared to 60 mph.

I'm no scientist so I'll just stick with my Don Julio 1942.

It's not a linear function, it's an exponential one.

D = Cd * A * .5 * r * V^2

Everything before V^2 is constant and 45-80 is only a 3x increase, not 10x in drag force.

March 10, 2022

21 hours ago, Grumpy Bear said:

Nope. Missed nothing. Your assumption "As you seem to suggest" is in error. I suggested nothing of the sort. Did you read the article? There was a lower limit at which aero drag is no longer the primary resistance. It gave that number in meters/second and MPH.

The most fuel efficient speed is the one that allows the motor to operate MAINLY in the highest gear AND in the most fuel efficient area of the fuel map. Normally in modern motors that is between one 1K and 1.5K. For most BOX like automobiles this happens to be between 43 and 53 mph. And that, as I said before is AIR speed, not road speed. 43 mph in my personal truck is minimum speed the 6 speed with a 31 inch tire and a 3.23 gear will shift up to high.

I don't argue physics anymore than I would argue the sum of 2 added to 2. Discuss yes, argue no. Have a nice day.

I didn't *argue* anything. You made an assumption, which was in error. Now you are backtracking because what I said was correct. You just restated what I previously stated in the response you are replying to.

Grumpy Bear · March 10, 2022

6 hours ago, 1454 said:

I didn't *argue* anything. You made an assumption, which was in error. Now you are backtracking because what I said was correct. You just restated what I previously stated in the response you are replying to.

Bull.

For some reason that escapes me people like to believe that saying a thing true makes it true. Like that I said something I did not. Or that I would care what a person that disregards such an obvious and easy to check truth thinks. What I said is part of a permanent record. I have a special dislike for liars.

Not my dog. Not my fight. Believe as you wish.

Edited March 11, 2022 by Grumpy Bear

JimCost2014 · March 11, 2022

To get this post back on track, hope this helps the OP. Remember the numbers are changing daily

customboss · March 15, 2022

Define Cd for each of our trucks or your guessing on drag effect vs velocity.

redwngr · March 18, 2022

The drag force can be expressed as:

Fd = cd 1/2 ρ v2 A

where

Fd = drag force (N)

cd = drag coefficient

ρ = density of fluid (1.2 kg/m3 for air at NTP)

v = flow velocity (m/s)

A = characteristic frontal area of the body (m2)

So, for any drag coefficient, the drag force will increase with the square of the velocity.

Edited March 18, 2022 by redwngr

TNTSierra · March 18, 2022

Throughout this week, I have been doing a little test on my truck. Since "I pay for my own gas", and it's out of control at $4.39 for premium here in Iowa. I have seen my mileage to work increase from 23.9 mpg's from 17.6 mpgs. Now this is just the trip meter and dash indicator on the truck but bare with me. Here is what I have done:

First when I take off, I haven't let the truck go above 2000 rpms, instead of accelerating at normal or a little aggressive speed.

Second, I have set the cruise at 67 mph, this seems like the sweet spot for my truck. The highway I travel is 65, so I don't want to go slower than that, because of idiots still driving 75-80 mph. The RPM's are around 1400 with the 10 spd.

I also have not remote started the truck all week. So after work, yes, it stinks when cold, but it has helped tremendously. I usually get a tank out of one weeks worth (Sunday-Sunday). I still have a little over a half a tank of gas today (243 miles to empty), last Friday I was at 138 miles to empty. All through the dash, I know, not truly accurate but still 100 miles is a big difference.

Just thought I'd share what I have found. Hopefully some of you guys can benefit from slowing down, relaxing, leaving 10 minutes earlier for work, enjoying the scenery, and just enjoying life and the simple things, because its chaos out there right now and we need a little comfort/peace.

Take care, hope this helps, have great weekend gentlemen.