If I read this correctly

and


I have the 4.10 Open Diff, so is this normal for the 2.3L?

so then,,



I should run atleast 30"s to get the best performance? and my current tire size is hurting my mpg?

am I reading this right?

 

mine came with a 3.73 open and a 7.5 axle.

 

My 2000 2.5L Sport came with 4.10 Open 7.5 diff.

 

That chart would apply for highway driving in 4th gear (1:1 ratio). I'm guessing that you would use 5th gear on the highway most of the time. 5th gear is overdrive and has a ratio of 0.8:1. So, all of the RPMs in that chart should be multiplied by 0.8 to get the true RPM in 5th at 65 MPH.

Your factory P225/70R15's are about 27.5" diameter. This corresponds to an RPM of about 3250 in 4th gear.

0.8 x 3250 = 2600

2600 RPM in 5th at 65. This is in the blue area where you want to be for best FE. It is also near the green area to maintain some highway performance. Looks like the Ford guys chose a good compromise.

 

i have seen a few but not many... and as far as i know all 2.3 or 2.5 motors came with the 7.5

 

ya mine came with a 7.5 open with 3.23 gears OH ya can we say slow with 32's thats why i have a L/S 3.73 now much better...