3.89 Ratio diffs

[Kieron20V]

Hi Chaps,

Im looking at swapping the narrow 01E I currently have in my v8 coupe for a 2.5 tdi one which should be able to handle the torque when I turbo the engine. (currently work in progress)
I dont want to pay mega bucks for a DSY or whatever flavour as chances are they will have been thrashed and need a rebuild anyway,

The only trouble is they are 3.89 ratio final drives, but are fairly cheap.

I can seem to find any 3.89 rear diffs that will fit straight into the rear subframe, so can anyone suggest any that would bolt it? Will a Urquattro fit with vacuum diff lock parts and same mounts?

Alternatively, I may get a matching diff from the donor car and pull it apart and use its pinion and crown set. Ive checked the bearings and they share the same bearings for the pinion shaft so should be straight swap.

Gear speeds calcualated with current tyres (225/40/17) and 7000 rpm redline are:

1 - 34mph
2 - 62mph
3 - 97mph
4 - 125mph
5 - 181mph
6 - 230mph

6th is veeery long so should make cruising long distances more viable.....

Ta for any info.

[UrS4boy]

Two threads for you that talk about 4.11:1 and 3.89:1 diffs and 01E transmissions.

1. http://www.s2forum.com/forum/showthr...highlight=3.89

2. http://www.s2forum.com/forum/showthr...highlight=3.89

[Kieron20V]

Two threads for you that talk about 4.11:1 and 3.89:1 diffs and 01E transmissions.

1. http://www.s2forum.com/forum/showthr...highlight=3.89

2. http://www.s2forum.com/forum/showthr...highlight=3.89

Thanks, I've read all that. I already know the gearbox I want is 3.89, it's b3 shaped rear diffs info I'm looking for.

Sure I could just pick a 3.89 ratio rear diff, but all the ones I've seen have different housings to the b3 one and would require custom subframe mountings and different props.

I think I'll just try to grab the cheapest 3.89 diff I can find and pull the crown and pinion and rebuild my current diff.

Unless of course there is a bolt in 3.89 rear diff out there.

Cheers,
Kieron

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[AndyP]

What TDi box are you looking at using? The one on my A6 is a DPJ and that's a 4.11:1 diff.

[Kieron20V]

What TDi box are you looking at using? The one on my A6 is a DPJ and that's a 4.11:1 diff.

As far as I know the dpj has a narrow first gear.

I'm looking at boxes from 98-04 a4/a6 2.5 v6 tdis. Can't remember code off top of my head.

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[Kieron20V]

Actually looks like dpj has wide first and flexible input shaft.

Just need to source one, the a4/a6 boxes are pretty commonplace and cheap that's why I chose that option.

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[caterpillar]

to what car do you want the 3,889... the a6 or??

[caterpillar]

for the a6/s6/ s4 c4 chassi use the diff from the autobox versons.. the may be 3,889 ( i have one at home)

[spink]

I think martinws has done what you are doing as he had a 2.8cq diff off me a few months back, not an easy thing to find though I would say if

[UrS4boy]

for the a6/s6/ s4 c4 chassi use the diff from the autobox versons.. the may be 3,889 ( i have one at home)

That is true of the early autobox C4s but the last ones, like 1997 and the 1998 C4 avants, I think, were 4.11:1. I know my 98 C4 A6Q V6 autobox quattro rear diff is 4.11:1.

[Kieron20V]

I think martinws has done what you are doing as he had a 2.8cq diff off me a few months back, not an easy thing to find though I would say if

Spink, do you have any dpj boxes for sale?

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[spink]

Spink, do you have any dpj boxes for sale?

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No,never had any apart from the one on my own car.It can't be any easy thing to find

[Error404]

Yup, V6 cq rear diff is the way to go - if you can find one

[popdemonic]

CKL rear diff from UrS6 automatic box has 3.89 ratio.I confirmed this but not sure if it's fitting straightforward on your chassis.

[AndyP]

Yup, V6 cq rear diff is the way to go - if you can find one

Try Audibits, he much have broken a few cq's