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I have a 1.6L viscous diff in my 1990 mx5. I happened to have old plate diff left over from a Mazda Familia 4x4 Rally car and it looked like it would fit.

I've ripped the diff out and the splines do fit into the diff, though the viscous diff has an extra gear on the end of the spline. Looks like I'll need to source a open diff spline to fit this centre. I haven't tried fitting it in the housing yet though it looks good in terms of overall size and bearing locations / diameters.

The center looks like this inside however with fewer clutch plates. http://www.z1auto.com/prodmore.asp?model=350z&cat=driveline&prodid=3489 It is also packed with some extra shims to tighten it up a bit. Perhaps its an rx7 plate diff?

Has anyone had any experience with this type of diff?

How suitable is it for motorsport?

regards,
Rick

I seem to recall (and this is a BIG memory stretch) that the rear diff centre from a Laser TX3 4x4 Turbo will fit an NA6 housing.

I would expect the Familia likely used the same diffs as the Laser.



I think Noddi85 has/had a Laser diff in his MX5, he's not really on the forums much but maybe try a PM anyway.

I found this great page, http://www.miataturbo.net/useful-saved-posts-8/diy-faq-all-your-answers-one-big-post-10821/ down in the diff section it talks about an RX-7 plate diff that fits into a 1.8 housing.

I better do some research and see if this thing fits into the NA housing or not. Are the splines on a 1.6 1990 the same as the 1.8 1994? I didn't think so, but if my splines fit then this must be a different diff than the RX-7 one and maybe it is out of the TX3 which ran all the same gear as the Mazda 323 / Familia back then.

Probably not a bad diff to run... might be worth getting this to work.

You will just need a pair of open diff stub axles and it will work no problems. The viscous stub axles are different lengths and can't really even be cut down and made to work properly. The plate diff will be good but will need to be reshimmed fairly regularly to keep it tight.

I may have a pair...... let me know if you need me to look.

After a bit more investigation the diff is the indeed the right size to fit into the 1.6 housing. The ring gear is only the 6" diameter and the hole centers are the same. The splines are correct except a little short by 5mm (I think this is because I only have the stub axles from the VSLD where one is shorter and the other is longer with an additional bit on the end) so an open diff stub axle will fit correctly I believe as they are a little longer.

So for those of you wanting a better LSD for a 1.6 try looking for a Mazda 323 (aka Familia) or Laser TX3 rear LSD diff.

Now it's just a matter of finding some open diff stub axles!