9 inch rear diff - ratios ?

[Panza]

What ratios are available for the Group A / WRC 9" rear diff ?

[SCS j1mbo]

3.6, 3.9, 4.4 and 4.8 iirc although im not 100% sure on the last

[M K]

and ive seen a few 5.1

[Panza]

Thanks
If I used a ratio of 3.6 in the rear diff I assume I would need 3.6 at the front too ?

Scratch the calculation. Look further down for the correct ones..

[nathan666]

What ratios are available for the Group A / WRC 9" rear diff ?

hi mate
ford offered 3.083 /3.250/ 3.417 / 3.636 / 3.818 / 3.9 / 4.091 / 4.273 / 4.444 / 4.667 / 4.889 / 5.111/ the ratio 4.8 was only used on the last WRC cars all the spec's are taken from the ford motor sport boreham books for you
i hope this helps

[Panza]

Which ratios are useable on the front with the 3.636 rear ?
Or more general: What is the max difference in ration front to rear ?

[Mike Rainbird]

Which ratios are useable on the front with the 3.636 rear ?
Or more general: What is the max difference in ration front to rear ?

It has to be matched - otherwise you will screw the centre VC. You do this with the relevant drop gears on the front .

[Panza]

Yes, I agree they have to be matched, but HOW closely ?

Look at these calculations (correct this time I hope). It seems to me that 5 rpm or 7 rpm is less than what would cause the centre diff to start locking up.