gas mileage/rpms

[zebz21]

what is the best rpm's to run at for the 4.0's i know for the 3.0's its around 3 grand but what about the 4.0's

 

[AllanD]

with my '93 4.0 engine t seems to turn into a complete pig ~2500rpm

The 4.0 doesn't like to rev without burning a lot more fuel.

AD

 

[Big Jim M]

Mine is bout the same as his.. Under 2500 gets pretty good..above starts loseing milage real quick. I shift at 18/1900 or less all the time and only get above that in 5th gear. Unless of course I'm entering a freeway or something that requires more quick!
Big Jim

 

[shadetree]

I have a 94 Explorer with cruise. It's best mileage is obtained at around 1500 to 1800 rpm. This is 55/60 mph. Best mileage to date is 21.5mpg. shady

 

[AllanD]

Hey, I run 235/75-15 tires and have 4.10 gears... which are just too much.

It restricts me to <70mph (actually more like 65-68mph) if I want to get >20mpg.

that's why the 4.10's are comming out and 3.73's are going in.
As soon as I finish prepping the 3.73 D35 pig I'm putting in...

BTW, my best mileage to date is 22.1mpg.

But I've only had the 4.0 in the truck and running for about 9 months, I finished my conversion late august, but didn't start driving it until september.

AD

 

[Bruce]

I have a 2002 with the 4.0, 4.10 gears 4x4 andP245 75Rx16's and im seriously thinking about dropping to 3.55's gears.

I have a 94 Exploder4x4 that has 3.27 gears with P235 75Rx15 tires on it and and it does a lot better on fuel mileage then my 02.

On another note my Brothers Ranger with 302 EFI AOD and 3.27's is pulling better than 24 miles per gallon.

 

[exbass94]

My Explorer has 3.27 gears and doesn't really get past 2500 rpm ever, even when accelerating. It usually gets around 15-17 mpg.