3.31 vs 3.73 Highway MPG Difference

[TacoJon]

Curious what the delta in highway MPG would be between the 3.31 and 3.73 gears in the gen 14 5.0 trucks. The window sticker is the same for both of them (24 highway), but I imagine testing is only done with one axle ratio.

"Get A PRius IF you CAre ABout MPG!" ..........I know. I am more curious than anything.

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[adyaro77]

? If I wasn't concerned I would be driving a Super duty ?
My 19' with 3:31 definitely got better Gas mileage than my 24' with 3:73. Different generations, but pretty sure the 19' was a 10 speed...don't remember.

 

[parkerdog]

Don't fear the gear used to be an old muscle car adage.

I had to buy a 4x4 in a 22 to get 3:73 gears. Now it's standard with the 5.0 I believe in the regular cab.

I've never reset the mileage computer since I bought the truck and it shows 18.4 avg. ymmv <(hey that actually is appropriate)

 

[TacoJon]

Don't fear the gear used to be an old muscle car adage.

I had to buy a 4x4 in a 22 to get 3:73 gears. Now it's standard with the 5.0 I believe in the regular cab.

I thought the regular cab got the 3.15's? Or maybe that is only regular cab 2WD.

 

[parkerdog]

I thought the regular cab got the 3.15's? Or maybe that is only regular cab 2WD.

maybe it's been a long time since I looked at the build and price. When I did it was a 5.0 and 2wd with a 3:73.

*edit*
Went and looked and it still only shows a 5.0 with a 3:73 available. It is the build and price though so take it with a grain of salt as always.

regular cab short bed

Another edit, I changed it to a long bed and it opened up different combos. So maybe build and price glitch or not. Short bed locks it into 5.0 and 3:73.

 

[jasonkosi]

I doubt it would be noticeable, there’s only like a 200 rpm difference at cruising speeds in 10th between the 3.31 and 3.73.
And yes, for 2024 the reg cab short box come standard with 5.0 and 3.73, in fact that’s the only option, 4x4 or not. Long box gives you some other options on the reg cab.

 

[ChuckNorris]

I found this pretty interesting. This guy's videos were pretty influential in my choice of the 5.0 with 3.73.

 

[Mike50]

In the expedition 4X4, you don't get a choice - its the 3.73. I think Ford's engineers know what's best. With a 10 speed transmission and built-in overdrive, there is little need for low numerical ratio's.

 

[roadPilot]

Curious what the delta in highway MPG would be between the 3.31 and 3.73 gears in the gen 14 5.0 trucks. The window sticker is the same for both of them (24 highway), but I imagine testing is only done with one axle ratio.

In the real world, the difference is zero. All it takes is a few extra stomps on the accelerator or a few extra spin ups of the turbo per tank of fuel and any mathematical difference that might have existed between the two will be gone.

 

[Mike50]

It would be nice to have an engineer response. I'm not one. But, I believe it is the case that an engine, given a given load, may run more efficiently at a slightly higher rpm than at a lower rpm. It depends on the load. The sweet spot for optimum rpm depends on the engine. This would depend on the torque and horsepower being provided vs what is required. If you run an engine too slowly and it is overloaded, even slightly, gas mileage will suffer. This is just meant to be an extreme example of why you may get better mileage at a higher rpm with the engine running in it's sweet spot for a given load.

 

[Aonarch]

In the expedition 4X4, you don't get a choice - its the 3.73. I think Ford's engineers know what's best. With a 10 speed transmission and built-in overdrive, there is little need for low numerical ratio's.

This.

10 speeds is way different than the old 4 and 5 speeds, where rear end choice had major impacts.

I went 3.73s, it was a no-brainer to me. It's a truck. I want as good as towing/ hauling performance as possible, and help with acceleration.

 

[roadPilot]

It would be nice to have an engineer response.

They already have. It's on the window stickers.

 

[ks54703]

Rear gear ratio is the multiplication of torque so at a 1 to 1 ratio transmission ratio (7th) 3.31 x 410 =1357, 3.55 x 410=1,455 , 3.73 x 410=1529. 410 is the torque output of the 5.0

Your moving a plus 6000 pound brick on wheels one can struggle with a short lever or one can move the same thing easier with a longer lever. It's your choice.

Another simple example is using a torque wrench with a 24" handle VS using a torque wrench with a 30" handle to do the same work let say re-torquing your F150 wheel lug-nuts at 150 pound feet. You will most often look down and verify the setting on the 30" wrench vs struggling with the 24" wrench.

 

[Saturnfire]

I have a 2024 XLT 5.0 FX4 with ~400 miles on it now. On my 87 mile round trip, that is mostly freeway driving 65-75 mph with no traffic, I was averaging 19.9 to 20.5 MPG with 3.73 gears. My previous 2013 F150 with 3.5 Max tow and 3.73 would get 19-22 mpg...(that was a 2wd and 6speed)

Also I am stuck with Commie e10 gas. When I was able to get e0. I would get 1.5 MPG more in my previous truck.

 

[Mike50]

They already have. It's on the window stickers.

I don’t consider a window sticker an explanation.

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