Diff Gears for 3spd auto XF - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

XF Falcon · 04-12-2003, 23:23

Gday, my auto xf has the standard open wheeler 2.72:1 (or some similar ratio) diff at the moment.

Ive got the chance to get off a mate, a 3.25:1 LSD diff centre to whack into my car.

Would that gearing be ok you rekon? Or would it revv too much on freeway driving and such?

My other choice is a 2.92:1 LSD centre to whack in place of mine.

What do you all rekon would be the best choice?:oo3:

South · 04-12-2003, 23:38

Whats she rev at currently on the freeway?

Totally different car, but friends worked VL V8 had 3.45s & 3 speed auto and sat on 3000rpm on the freeway.

If i shift my fairmont into 3rd on the freeway it sits up around 2800rpm and its got a 3.23 LSD...

I guess the question is, what do you hope to achieve from this swap? Just the ability to chuck a snakie, or are you wanting the car to get up and boogy from the lights?

XF Falcon · 04-13-2003, 00:03

Not too sure what it revs on the freeway as theres no tacho in my car :( Anyone know roughly what rpm it does at around 100 - 130 k's?

But basically im after better performance off the line as well as being able to know that its always going to light up both tyres, and its always going to kick out in the wet.. and not just when it wants to (i think my open wheeler diffs starting to play up)

South · 04-13-2003, 00:10

3.25 sounds fine to me then, its not a HUGE step like other people choose. If your only on the freeway twice a day for a short period of time then it shouldnt worry the old hip pocket. If however you make trips up north or down south a fair bit then it might cost a few extra dollars.

With that said though, running your engine at slightly higher revs wont use much more fuel. Your smack bang on/in your torque range, so the cars doesnt have to work to overtake or just speed up slightly. I can see it being more effiecient. Ive tested the fuel economy at 100 and that read 8.0L/100km, and i tested it at 150, and that reported 10.0L/100km. So i was getting 50km further & quicker for only 2L more fuel usage, which is a shit load more economical, and that due to me sitting smack bang in the middle of the torque curve.

Theres more to it than that, but yeah, go for it, have some fun :D

Slash · 04-13-2003, 04:19

ive got a standard 3.23 diff in my auto xf and she revs about 2700 at 100 k's. not to bad on fuel either from the old 2.78. i reckon u should go for it.

OverDose · 04-13-2003, 20:39

just curious how much do the 3.23 lsd diffs go for?

$hadow · 04-13-2003, 23:39

hey i have a XF falcon s pack that has a lsd not sure on the size or anything but its all stock and at 110 i rev at about 2100 i also have the 3 speed aiuto

XF Falcon · 04-14-2003, 06:57

Great fellas, ta for the info. looks like i'll try get the 3.23 then.

Overdose, if all goes well i'll be getting the 3.23 (non-lsd) diff for nothing, and then all i'll have to pay is some place to transfer the gears into a LSD 2.92 that I can also get for nothing :)