mx5 diff problems

[PorkChop]

Originally Posted by Short

1 comment on that - the bolts are in shear. eventually, it will snap them if there not tough enough.

As for solid mounts all round, you need to allow SOME movement due to chassis twist. No matter how braced it is, the chassis will twist in corners and over bumps. the mild steel diff cage will twist, but the cast diff wont. To be honest, I think a stiff mounted diff is more likely to fail than a bushed diff. Think how much damage a car would get with no suspension at all?

One common mod on MX5s is to stiffen the diff rubbers, because tired mounts can give a reduction in gear change quality due to excessive movement (if I remember what I read correctly, it was some time ago and I can't find the bookmark). The mounts could be stiffen by filling with shoe goo, fitting diff void fillers or stiffer mounts (which I think Mazdaspeed did along with uprated engine mounts).

The Sierra diff is solid mounted in these cars. AFAIK there have been no issues with diff mounting failures.

There are several kit car manufacturers using solid mounts on their MX-5 based builds; GBS and Roadrunner Racing are two certainties because I have seen their cars IRL. Well, GBS cut off the arms and solid mount the centre part of the diff upper.