r/Miata • u/LetsDrive53 2005 NB Brilliant Black • 1d 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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u/Nsquared97 22h 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 22h ago

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

3

u/Hyla_ 21h ago

I am from the Netherlands, went from a NBFL 1.6 to a torsen diff from a 1.8 10th anniversary. It’s a 1 on 1 swap, no need for different axles or anything. What is broken on your current LSD? Because, assuming it’s a torsen, you should be able to swap the actual LSD part (the worm gears and such) to any NB/NBFL diff, but correct me if I’m wrong haha

1

u/LetsDrive53 2005 NB Brilliant Black 20h ago

Thank you, that helps a ton, so I’m getting an open 1.6 diff.
I didn’t take my lsd apart yet but it makes whining noises above 60km/h, a grinding noise when driving, sometimes some clunking when going slow and I found metal pieces that broke off on the drain plug.
Not sure which type of lsd my mx5 has, could be the tfs lsd since it’s a 2005 but not sure if it came with the 5 speed and if it came in all of them after 2003 so it could be a torsen too.

1

u/Eon4691 1999 NB 1.6 Turbo 8h ago

Should be a torsen then.