Suitable diff ratio suggestions - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

jAcKaL · 10-23-2003, 01:20

Gday guys,

What diff ratio would you recommend to fit to an xf that runs a std auto and efi 6 mill with minor engine mods and exhaust/headers in order to get quicker off the line? I believe it currently has a 2.77 ratio with LSD.
I was thinkin of fitting a 3.25 ratio so it wouldnt impact a whole deal on the cruisability of the car that runs a speed auto box. Any suggestions? Are there other issues I should factor in when making a decision?

cheers,
jAcKaL

danege · 10-23-2003, 01:27

If you dont do any highway driving or care about the revs your doing get 3.9 or 4.11 gears.

If you do a bit of highway driving i would suggest 3.45 or 3.7 gears.

This should help a fair bit with takeoff

TIKFD6 · 10-23-2003, 03:10

I have 3.9:1, i still get 28mpg on the highway.
And a nice punch off the line. 4.11 is to low

sylox · 10-23-2003, 12:35

Dont go to low with the new diff ratio

The ea before the one I have now. I put a lower diff ratio in it. went from 2.9:2 standard
up to 3.0:8
Made a fairly good improvment but remember if you have a manual you'll be changing gears more often so you might lose time there.
i went from getting 100k's out of second to only getting 85k's
So just bare it in mind.
Sure go super low if you have a race car but if you have to use it as a daily driver I wouldnt go too far with it.

WBT56 · 10-23-2003, 15:06

Don't go lower than 3.23. The 4.1 doesn't like to rev, and makes good torque. We recently changed an XF manual from 3.5 to 3.08 and it went better.

NZ · 10-23-2003, 16:23

What are the diff ratios that are avalible? Standard an non standard. I know the standard ones are 2.77, 2.92, 3.08, 3.23, 3.27, 3.45, 3.7, 3.9 and 4.11. Ive heard of 3.5 as a non standard are there others?

Im looking at changing my diff ratio from 3.27 (V8 manual) but I think going to a 3.45 would be a bit pointless since its a mall change and 3.7 would be a bit short for the highway.

WBT56 · 10-23-2003, 19:52

ED XR8 = 3.27. EL XR8 = 3.45. Obviously Ford thought the small change was worthwhile. Although mathematically small, you will notice the improvement going from 3.27 to 3.45.