JDM diff type?

Engines, Transmissions & Final Drive questions and answers

Moderators: timk, Stu, zombie, Andrew, The American, Lokiel, -alex, miata, StanTheMan, greenMachine, ManiacLachy, Daffy

RS2000
Racing Driver
Posts: 680
Joined: Mon Nov 25, 2013 7:38 am
Vehicle: NB8A
Location: Newcastle

JDM diff type?

Postby RS2000 » Fri Jun 13, 2014 6:26 pm

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

User avatar
Regie
Speed Racer
Posts: 4259
Joined: Thu May 15, 2008 3:02 pm
Vehicle: NC - V8
Location: Sydney

Re: JDM diff type?

Postby Regie » Fri Jun 13, 2014 8:05 pm

3.9 Torsen as a guess
MY07 NC, Mazdaspeed Body, Ohlins, Full GWR Exhaust, 17x9 RPF1's, 4.1FGR and lots lots more

User avatar
hks_kansei
Speed Racer
Posts: 6154
Joined: Tue Feb 03, 2009 10:43 am
Vehicle: NB8A
Location: Victoria

Re: JDM diff type?

Postby hks_kansei » Fri Jun 13, 2014 8:41 pm

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.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)

User avatar
zossy1
Racing Driver
Posts: 1979
Joined: Wed Aug 18, 2010 8:48 am
Vehicle: NA8
Location: Southern Highlands, NSW
Contact:

Re: JDM diff type?

Postby zossy1 » Fri Jun 13, 2014 11:57 pm

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.

emily_mx5
Racing Driver
Posts: 1720
Joined: Wed Aug 03, 2011 5:57 pm
Vehicle: NB SE
Location: Sydney

Re: JDM diff type?

Postby emily_mx5 » Sat Jun 14, 2014 9:02 am

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.


Sent from my iPhone using Tapatalk

User avatar
timk
Racing Driver
Posts: 1928
Joined: Fri Dec 31, 2004 3:16 pm
Vehicle: NC

Re: JDM diff type?

Postby timk » Sat Jun 14, 2014 10:33 pm

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

spikey
Fast Driver
Posts: 453
Joined: Mon Mar 14, 2005 1:32 pm
Vehicle: ND - 2 GT
Location: Perth W.A.

Re: JDM diff type?

Postby spikey » Tue Jun 17, 2014 12:05 am

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 :cry:

RS2000
Racing Driver
Posts: 680
Joined: Mon Nov 25, 2013 7:38 am
Vehicle: NB8A
Location: Newcastle

Re: JDM diff type?

Postby RS2000 » Tue Jun 17, 2014 9:53 pm

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

emily_mx5
Racing Driver
Posts: 1720
Joined: Wed Aug 03, 2011 5:57 pm
Vehicle: NB SE
Location: Sydney

Re: JDM diff type?

Postby emily_mx5 » Tue Jun 17, 2014 10:24 pm

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


Sent from my iPhone using Tapatalk

User avatar
david_syd_au
Racing Driver
Posts: 935
Joined: Mon Feb 07, 2011 10:27 am
Vehicle: NC
Location: Bilpin, NSW

Re: JDM diff type?

Postby david_syd_au » Wed Jun 18, 2014 8:39 am

A 1999 Roadster RS would also have yellow bilstein shocks, and probably ABS
2011 NC LE "Black Beauty" (ours) | 2006 NC race car "Shazza" (his) | 1998 JDM NB race car "OMG" (hers) | NC Trailer


Return to “MX5 Engines, Transmission & Final Drive”

Who is online

Users browsing this forum: No registered users and 79 guests