Sponsored

steevenk

Black Diamond
Well-Known Member
First Name
kurt
Joined
Aug 18, 2020
Threads
1
Messages
87
Reaction score
187
Location
Chicago
Vehicle(s)
'05 AWD Astro, '90 G20 Van, '14 Subaru Forester XT
Your Bronco Model
Black Diamond
He changed his initial post from 2x speed is 4x fuel to 2x speed is 4x "power".

I say "power" because his use of "power" is wrong. He is discussing drag force. Power is Force x Velocity or P = Fd*v. If we only discuss Drag force (and neglect any other forces), then Fd = 1/2*rho*A*Cd*v^2 where rho is air density, A is cross sectional area, Cd is coefficient of drag and v is velocity. So Power, P = (1/2*rho*A*Cd*v^2)*v. Assuming that A, Cd and rho are constant between the 2 states, P ~ v^3. So power required for maintaining steady state at speed V2 = 2*V1 you get P2/P1 = (V2/V1)^3 = ((2*V1)/V1)^3 = 8 => P2 = 8*P1.

For anyone reading this, If you disagree with me, please be respectful in your reply.

edit: tagging @WuNgUn
Power to overcome drag is a cube of speed. If this is what you were trying to say you should have said it, though that doesn't really matter to what I was trying to point out.

The point I was making doesn't matter whether it is specifically 4x or 8x, and doesn't really matter if we are talking specifically fuel or power. You sure seemed to be implying that changing gears to keep the engine RPM at 2000 when increasing speed from 25 to 50 would require an insignificant amount of additional fuel/power. I was pointing out that If you were trying to say that it would take a lot of extra power/fuel to increase the RPM from 1000 to 2000 once you shifted, just not 8x a lot, then you did bad job of communicating that. You did seem to keep implying through your posts that the transmission makes a much more significant difference in required power/fuel when doubling speed then it actually does during normal driving.
Sponsored

 

adxl

Outer Banks
New Member
First Name
John
Joined
Mar 28, 2021
Threads
0
Messages
3
Reaction score
2
Location
Atlanta
Vehicle(s)
Sportrac Boxster
Your Bronco Model
Outer Banks
Hilarious with people posting MPG when they drive 80 and 90MpH 🤷
It probably doesn't matter much to Americans who pay what, $2.75 a gallon and think thats a lot, but you'll need FOUR times more power every time you double your speed...
Doesn't matter if it's 25/50MPH or 100/200MPH.... 4X as much.
https://www.caranddriver.com/reviews/a37103139/2021-ford-bronco-first-edition-v6-by-the-numbers/

Great pictures and complaints by Car and Driver about low mileage (who really cares, go buy a Prius) somewhere about 17 to 18 mpg.
 

jaspercasidino

Base
Well-Known Member
Joined
Jul 18, 2020
Threads
7
Messages
1,070
Reaction score
2,940
Location
PNW
Vehicle(s)
2022 Bronco
Your Bronco Model
Base
Clubs
 
Power to overcome drag is a cube of speed. If this is what you were trying to say you should have said it, though that doesn't really matter to what I was trying to point out.

The point I was making doesn't matter whether it is specifically 4x or 8x, and doesn't really matter if we are talking specifically fuel or power. You sure seemed to be implying that changing gears to keep the engine RPM at 2000 when increasing speed from 25 to 50 would require an insignificant amount of additional fuel/power. I was pointing out that If you were trying to say that it would take a lot of extra power/fuel to increase the RPM from 1000 to 2000 once you shifted, just not 8x a lot, then you did bad job of communicating that. You did seem to keep implying through your posts that the transmission makes a much more significant difference in required power/fuel when doubling speed then it actually does during normal driving.
I did say power is proportional to cube of speed (P ~ v^3) and showed the work. Other guy was saying that power is proportional to the square of speed. I was laying out the framework so people can see the difference between force and power.

I am also specifically speaking to steady state conditions and ignoring transient effects (like in the case if you decided to drive XX miles at speed 1 and XX miles at speed 2). Sorry that I am not communicating that clearly. Point of discussion changed somewhere in the middle of the conversation from fuel economy to power required. All I was trying to showcase with various transmission statements and examples is that transmission has an effect on fuel economy and going 2x as fast doesn't require 4x the fuel. Another user posted this link and the chart. It also matches what we know from years and decades of driving. We are not quadrupling our fuel consumption once we move from the city streets to highway driving.
 
Last edited:

nminus1

Banned
Base
Banned
Banned
First Name
Henry
Joined
Jul 16, 2020
Threads
6
Messages
525
Reaction score
992
Location
High Desert So Cal
Vehicle(s)
Chevy Duramax, Trailblazer, and Ford Escape
Your Bronco Model
Base
Boy this post went off the rails with engineers. Its ok I like engineers in my line of work they are either my savior or my worst nightmare.
I think the most importance thing to take away this post is MAKE SURE YOU GET WHAT YOU WANT. After waiting nearly 2 years when I get my Bronco next year, I do not want to have regrets about my order. Order what you really want, JMO
 

termin8

Outer Banks
Active Member
First Name
Dave
Joined
Feb 2, 2021
Threads
1
Messages
39
Reaction score
126
Location
Ontario, CAN
Vehicle(s)
2013 ford edge
Your Bronco Model
Outer Banks
Came back from a 6 hour trip this past weekend and have these comments. A combination of city stop and go and highway max 60mph as was only a 2 laner road. I got 23mpg just like the window sticker says, so very pleased with that. There were times had to pass slow moving farm equipment vehicles, and boy the 2.7 door had great giddy-up. We had the 2 front roof panels off and just loved it, they stored nicely in the bag at the back cargo area secured to the tie hooks and the straps around the backseat head rests. The seats were super comfortable, no moving around like my other vehicles when your ass gets sore. Radio I know others complained about it, but it was fine for us even with the roof off. As far as washing it goes, when we got home there were lots of bugs splattered on the front bumper and dust everywhere from some gravel roads we were on. Every vehicle I've owned there is always some area after washing then drying that just keeps oozing out water no matter how many times you try to dry it. I think the engineers did a great job in that area(is there even a position for someone to make sure washing and drying a vehicle isn't a pain) my OBX grill has fewer slots than other grill styles so wonder what others have thought about their experience. Anyways to date, I have no complaints and hope they can release those on dirt mountain soon enough for you to enjoy as well.
 

Sponsored

PotatoSalad

Badlands
Well-Known Member
Joined
Jun 4, 2021
Threads
10
Messages
109
Reaction score
160
Location
Houston, TX
Vehicle(s)
2014 Ford Fusion
Your Bronco Model
Badlands
The ugly…the soft top is a pain at best. When stowed all of the way, you lose entire visibility through rear mirror. Removed completely it would solve the problem, but then you wouldn’t have the top available. There is a ton of road noise as well as warm air circulating around the cabin. The three removable panels are a real pain to get back in place properly, easily as bad as the Wrangler soft top, which is a similar nightmare as well.
How is the visibility out of the back when the soft top is all the way up? I went to a dealer today to look at their demo Bronco (no test drive) and they had the soft top folded all the way down. I definitely see what you mean about no visibility. The rear view mirror is useless.

I've been considering changing my order from MIC to soft top, but am concerned about visibility in general with the soft top. How is it when it's actually on?
 

SuperDave150

Outer Banks
Well-Known Member
First Name
David
Joined
Apr 5, 2021
Threads
8
Messages
319
Reaction score
460
Location
Albuquerque, NM
Vehicle(s)
Ford F-150, Ford Edge
Your Bronco Model
Outer Banks
Clubs
 
Hilarious with people posting MPG when they drive 80 and 90MpH 🤷
It probably doesn't matter much to Americans who pay what, $2.75 a gallon and think thats a lot, but you'll need FOUR times more power every time you double your speed...
Doesn't matter if it's 25/50MPH or 100/200MPH.... 4X as much.
18 MPG given sounds about right. Better than a Taco on 32’s (I know 2 different people who have 32’s on their Taco - both get 16-17 MPG). My brother has a stick shift Taco, he drives fast; curiously, he changes the subject any time I ask about MPG with his Taco. 🤣
 
OP
OP

Spider Jeff

Big Bend
Member
First Name
Jeff
Joined
Aug 15, 2021
Threads
4
Messages
13
Reaction score
216
Location
The Woodlands, Texas
Vehicle(s)
2016 F150 1967 Vette 2021 Bronco
Your Bronco Model
Big Bend
Visibility is fine with top up, side mirrors are especially good with two piece blind spot mirror.

Another point I forgot to make is zero means zero on the fuel gauge, I hit zero miles remaining as I pulled to the pump and it took 20.6 gallons before the auto shutoff, in a 20.8 gallon tank.

My F150 has about two gallons left when it hits zero, about one if towing due to the method used to calculate remaining fuel.

just a warning, especially for someone wheeling!
Sponsored

 
 


Top