Jag Diffs - Tips and Problems

[maxcat]

I'm trying to get information about independent Jaguar diffs - either XJS or XJ6.

Does anyone have any information about the similarities and differences between the XJ6 and the (preferred) XJS diff ranging from mounting differences and ratios?

Thanks

Max

[bnewsom]

The xj6 and xjs diffs are basically the same, at least internally. They are dana 44's using same gear sets as other d44 applications. They are very strong units and are clean looking with disc brakes mounted inboard near the center section. V12 cars had posi units and others had open diffs. From around 82-87 they used 2.88 gears and earlier years had 3.0somethings, 3.54 and some I believe had like 4.11. Mounting info I don't have but hope this helps some.
Bob

[maxcat]

Thanks Bob it did help.

A few more queries though: What is the ratio typically chosen by T-Bucket drivers and does the Jaguar stud pattern take Ford rims?

[bnewsom]

Not sure what ratio to recommend because it would realy depend on transmission type and personal preference. I would guess anywhere from 2.88:1 with a non overdrive trans to a 4:11:1 with an overdrive trans. Jaguar wheel bolt pattern on the earlier years up to 1987 I know and maybe a little later is the Chevy 5 on 4.75".
Bob

[maxcat]

I'll be running a reconditioned but stock 3 spd Turbo 350 trans and 350 engine.

Driving will be pretty much summer beach stuff so no need for high speed - I want acceleration over top end. Ratio for this kind of driving might be?..

This site may be of interest to other readers interested in Jag rear ends:

http://www.erareplicas.com/fia/jagsusp.htm


Max

[bnewsom]

With that light of a car, I would run in the low to mid 3's. No need to turn the extra rpm's that you would have to with something like 4:11's unless you are going to run really large tires(over 28") or are going racing.
Bob

[maxcat]

I've been offered an XJ12 diff - is there anything different to be aware of with this model?

Having done a search there are a few Cobras running with them, but I can't find a lot of information about the costs/benefits of going to the (apparently) finer toothed XJ12 diff.

Max Christoffersen

[bnewsom]

XJ12 is good! Should be a positive traction differential. I'm not aware of a difference in teeth though.
Bob