gas millage???

[off_road_junkie21]

ok i am swaping in a 4.0 into my 87 ranger xlt ext 4wd what kinda millage can i get.i am rebuilding it before i put it in. it is going to be port polysed,port matched.msd,hearders, bigger throttle body, throttle body spacer,cold air intake to. my 2.9 get about15 to 20 on the highway it is boried 40 over. thanks guys

 

[Fusion]

It was a different gas mileage thread i was thinking of.

I've not had my truck long enough to make a good report on gas mileage. With the 35's, 10" of lift and carrying 5 wheels, 4 tires, 2 rear bumpers, a set of cyl heads, 2 axles and a couple of boxes of misc stuff it got 15.5mpg on a parkway with some fairly steep inclines. I'm guessing it might get 17mpg running 55-60 on flat ground with no load but that's a guess. I wasn't running the supercharger though. I've been told it would actually help fuel mileage a little due to pulling the hills with less throttle applied.

 

[BlackBII]

I was getting about 17 in one of my BII's with a 2.9, after swapping in a 4.0, I actually got better mileage, like 20.

But the 2.9 was about to blow and the 4.0 had hardly anymiles on it......

 

[Big Jim M]

Milage is all about perfect matching of the compnoents and mild use of the vehicle. By placing a larger throttle body on there you will change the way the intake keeps up it's velocity and prolly will LOSE milage as a result. Any gain will be at very HIGH rpm which is the opposite of milage.. The TB spacer is dubious at best and won't help a thing in a computer controlled engine. A spacer can help a carbed engine at A CERTAIN RPM as the spacer can increase velocity of the mixture to the desired speed at THAT rpm. In a computer engine it just gets in the way of the thousands of hours the engineers have spent trying to get the best possible milage from their design of the engine.
Big Jim

 

[KELLY88]

I've got a 4.0 with about 195k on odometer. Well maintained and gets about 19 around town last time I worked out the numbers.

 

[Jarvill8]

I have a 99 ext cab 4.0 with 4x4, 31" BFG A/Ts, and an automatic transmission and I consistently get 17-18.5 mpg in my truck with combined driving. I do, however, drive like a very old woman and never drive it above 2500 rpms unless I accidently pull out in front of a semi.