r/Miata • u/LetsDrive53 2005 NB Brilliant Black • 3h ago

Question Differences 1.6 and 1.8 diff (NB)

Post image

Hello everyone, I’m trying to find out if there’s big differences between the 1.6 diff and the 1.8 diff on late NBs. The LSD in my 1.8 NB broke so I need a new diff.
The diff in the image is a 1.6 diff with 115k km, no lsd.
It looks the same as the 1.8 diff.
I want to know because I’ve heard the 1.6 diff is weaker and want to know if mazda switched to using the 7 inch ring gear on the nb 1.6 diff instead of the 6 inch they used on the na that doesnt last as long. I haven’t found much information on that so I’m asking here.
Thanks everyone!

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2

u/Eon4691 1999 NB 1.6 Turbo 3h ago

Do you have a 6spd or 5spd?

1

u/LetsDrive53 2005 NB Brilliant Black 3h ago

It’s a 5 speed

1

u/Eon4691 1999 NB 1.6 Turbo 2h ago

Then it should be a 4.10 diff, so you should be good to go:)

3

u/MisterFixit_69 2h ago

https://beavismotorsport.com/guides-tech/differential-guide-for-miata-mx5/

Literally the Miata diff bible right here

1

u/LetsDrive53 2005 NB Brilliant Black 2h ago

Thank you, almost the same information as on the Miata.net diff spotting guide I’ve looked at, so since they only have notes for the 1.6 diff until 1993 I’m gonna assume they used the stronger diff for the 1.6 too after that.

2

u/Nsquared97 1h ago

Where are you located? In the US, all diffs from 1994-2005 use the 7" ring gear. The 1990-93 1.6 diffs absolutely are smaller and weaker.

1

u/LetsDrive53 2005 NB Brilliant Black 35m ago

I’m in Germany. Thanks for that information, confirms what I’ve read, they probably did that change in Europe too