Diff options into a 318i cab. ..?

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jimbom30cab
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Post Sun Feb 24, 2013 7:56 pm

HI,

I think I have the small case diff fitted, it's the factory fit 4.1 ratio from a K reg 318i diff

Anyway, I want to fit a taller diff say a 3.46 and all the doffs I have seen for sale are medium case.

Is this a straight swap or is there other parts such as the drive shafts needed also

Sorry if this has been post loads of times. :o: :o: :o:

Thanks


Jim
Grrrmachine
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Post Sun Feb 24, 2013 8:25 pm

I don't think you'd want to go all the way down to 3.46. That feels blunt enough on a 325i, let alone a weedy 1.8litre four-pot. The absolute lowest fitted to a 318i was a 3.64, and I bet that was dog-slow.

All the diff info is here:

http://www.e30zone.net/e30zonewiki/inde ... fferential
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DaniTD
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Post Sun Feb 24, 2013 8:38 pm

Being a 318i and more being a cabrio (more weight), I wouldn't go further than 3.91. I know of people that changed from 4.10 to 3.91 and they are happy with it (lower rpm when cruising on highway), although accelerations seems to be a bit flawed. I personally have on my 318i 4 door a 3.91 and I wouldn't recommend you lower than that.