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What factory diff came on a JDM '99 NB (NB8C) with a 6 speed gearbox ?

Open or viscous lsd or torsen? Ratio?

Thanks in advance

3.9 Torsen as a guess

Could be anything, Japan you could option different ones.

'99s were 4.1 ratio, but I;m not sure if that applied to the 6 speed.

As for the diff type, could be open, or torsen.

If it's from an RS (which I expect it is, since it's a 6 speed) it's more likely to be an LSD since I think they were standard on the RS.

hks_kansei wrote:Could be anything, Japan you could option different ones.

'99s were 4.1 ratio, but I;m not sure if that applied to the 6 speed.

As for the diff type, could be open, or torsen.

If it's from an RS (which I expect it is, since it's a 6 speed) it's more likely to be an LSD since I think they were standard on the RS.

Are you sure? Dad pulled an open 4.3 out of a 99 JDM NB8C (5 speed) last week. No doubt it was factory installed.

I know the ADM was 4.1 but I suspect the car we have was representative of all JDM 5 speed 99-00 NB8Cs.

Gotta be careful with your series names, all jap NBs are called nb8c (part of the vin)
Where are we use nb8a/nb8b/nb8c to distinguish them.
So you are talking about a jdm nb8a in both cases, pretty sure the RS had a torsen diff.


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I think all 6 speed NB JDM MX-5s have TorSens.

The JDM NB's with 6 speeds ran the 3.9 Torsen unlike the ADM with the 3.63 open diff, I don't think any of the JDM models had an open diff, they were all sent here instead

Thanks for all replies - seems it's most likely a 3.9 Torsen.

The car has a 'Roadster' badge - I assume that's what you mean by 'RS' ?

Cheers

No.
Roadster is the Jap name/badging.
RS was a particular model in japan, special edition with lots of goodies.


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A 1999 Roadster RS would also have yellow bilstein shocks, and probably ABS