Diff ratio compatibility

Archives of Posts to the NZ MX5 List back in 2003
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PeterD

Diff ratio compatibility

Post by PeterD » Tue Jul 08, 2003 6:53 pm

Does anyone know if the Mazda and Torsen Diffs can exchange crown wheel
and pinion sets. Specifically a 93 4.1:1 Torsen using a 4.3:1 Mazda,
assuming 7"?

lou Girardin

Diff ratio compatibility

Post by lou Girardin » Wed Jul 09, 2003 4:07 pm

The 1.6 and 1.8 diff insides do not interchange.

jeff

Diff ratio compatibility

Post by jeff » Wed Jul 09, 2003 4:15 pm

Hi Peter


If you havent already, check out http://www.solomiata.com. If it doesnt fit well, Ill take it off your hands for a fair price! J


I take it yours is a '99+ with a 7" 4.3 diff then?


Jeff

96 Torsen-less in Akl


PeterD <peter.dixon@paradise.net.nz> wrote:

Does anyone know if the Mazda and Torsen Diffs can exchange crown wheel and pinion sets. Specifically a 93 4.1:1 Torsen using a 4.3:1 Mazda, assuming 7?

PeterD

Diff ratio compatibility

Post by PeterD » Wed Jul 09, 2003 5:15 pm

Thanks, mine is a 93 4.1:1 7" Torsen. I'm after the 4.3. The solomiata
is very informative but doesn't specifically say that they are
interchangeable with the Mazda item.

As the Mazda price is $850.00 it's a bit of a risky gamble. Mazda state
that they do not support the Torsen and accordingly can give no
information. At $850.00 you think they might ask the question for me.

I am of course after the Crown wheel and pinion, but would be interested
in a swap should another Torsen owner want a higher ratio.

Rgds

PeterD

PeterD

Diff ratio compatibility

Post by PeterD » Wed Jul 09, 2003 5:17 pm

Thanks Lou, I'm looking for the 99 4.3:1 crown wheel and pinion. They
are both 7" but I'm not sure if the Mazda is interchangeable with the
Torsen.

Rgds

PeterD

Fletch
Yes. I might just know (Trusted Advisor)
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Diff ratio compatibility

Post by Fletch » Wed Jul 09, 2003 5:34 pm

The Torsen and open diffs are both Mazda diffs...

The ring and pinion can be swapped, as a set, between open and Torsen
diffs...

You cant mix ring gears and pinion gears from different sets..

Clear?

Fletch.
Red '90. Many n/a mods and Link ECU

jeff

Diff ratio compatibility

Post by jeff » Wed Jul 09, 2003 5:37 pm

<brain fart> ... pure speculation but I think it will fit since the Aussie Guru torsen (http://www.mx5mania.com.au ) seems to universally fit the NA8 and NB models, all of which are 7" , but of varying ratios (http://members.aol.com/solomiata/RingandPinion.html )

You may be able to find something in the MiataPower archives as well (www.miatapower.net)

hope that helps!


PeterD <peter.dixon@paradise.net.nz> wrote:


v\:* {behavior:url(#default#VML);}o\:* {behavior:url(#default#VML);}w\:* {behavior:url(#default#VML);}.shape {behavior:url(#default#VML);}
Thanks, mine is a 93 4.1:1 7 Torsen. Im after the 4.3. The solomiata is very informative but doesnt specifically say that they are interchangeable with the Mazda item.


As the Mazda price is $850.00 its a bit of a risky gamble. Mazda state that they do not support the Torsen and accordingly can give no information. At $850.00 you think they might ask the question for me.


I am of course after the Crown wheel and pinion, but would be interested in a swap should another Torsen owner want a higher ratio.


Rgds


PeterD

PeterD

Diff ratio compatibility

Post by PeterD » Wed Jul 09, 2003 5:47 pm

Thanks Fletch, not quite clear though. Mazda makes two diff options, the
"open" and VLSD. The Torsen is supplied by Torsen and fitted as a
factory accessory by Mazda.

Mazda NZ will sell me a 4.3:1 set for the Mazda 7" but are unable to
advise if it will fit the Torsen.

If I can be sure that the Mazda will fit the Torsen then I will be back
at Mazda Wn tomorrow with $850.00 in my hand. Of course if it arrives
and doesn't fit then I have two very expensive paper weights, and an
angry Wife to deal with.

PeterD

Fletch
Yes. I might just know (Trusted Advisor)
Yes. I might just know (Trusted Advisor)
Posts: 119
Joined: Thu May 18, 2006 10:11 pm
Location: Auckland

Diff ratio compatibility

Post by Fletch » Wed Jul 09, 2003 5:56 pm

Randy Stocker of www.solomiata.com says they fit...

For an MX-5/Miata/Eunos Roadster, the VLSD was only available in the 6" diff
for the 1.6 NA cars.

The Torsen is an LSD unit that bolts into the standard Mazda 7" diff as came
with all the 1.8 MX-5/Miata/Eunos Roadsters...

Different year 1.8 MX-5 (etc) came with different sets of 7" ring/pinion
ratios... but they all bolt into the same 7" diff housing... and they can all
have a Torsen unit fitted or not fitted...

I have not done this personally myself, but that is what I've been reading
many times for the last five years, and I've never seen any one contradict
it...

(and although it doesn't apply to your issue, you can equally transfer the
"can of goop" viscous unit between 6" diffs if you want)

Good luck.

Fletch.
Red '90. Many n/a mods and Link ECU

Gary Morrison
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 100
Joined: Sun Jun 04, 2006 3:24 pm
Location: Wellington

Diff ratio compatibility

Post by Gary Morrison » Thu Jul 10, 2003 1:34 pm

Thanks, mine is a 93 4.1:1 7 Torsen. Im after the 4.3. The solomiata is very
informative but doesnt specifically say that they are interchangeable with
the Mazda item.

I have a 1.8 torsen in my 1991 car. I didn't worry about the changed diff
ratio, any reason why you want to change it?

SLYDIT
Keep calm, Forum Moderator here.
Keep calm, Forum Moderator here.
Posts: 1610
Joined: Sun May 21, 2006 6:18 pm
Location: In the Garage.

Diff ratio compatibility

Post by SLYDIT » Thu Jul 10, 2003 4:37 pm

$850 sounds like a LOT of money for a .2 ratio
change!! Have you thought about getting a used 7" with
the 4.3 ratio instead?? Why are you changing??
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

PeterD

Diff ratio compatibility

Post by PeterD » Thu Jul 10, 2003 6:11 pm

Thanks, If you can find a cheaper one then I'm keen. Reasons, better
0-100 performance, not too drastic to alter cruising speed, no change in
speedo gear, will out perform all those with 4.1 not wanting to spend $.

Car is being built for Targa.

PeterD

Gary Morrison
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 100
Joined: Sun Jun 04, 2006 3:24 pm
Location: Wellington

Diff ratio compatibility

Post by Gary Morrison » Fri Jul 11, 2003 4:21 pm

Perhaps the slight difference in gearing could be made up with tyres that are
slightly undersized... I don't know if there is a fitting that would do it...


On Thu, 10 Jul 2003 05:37:04 +0100 (BST), glenn roberts wrote:

$850 sounds like a LOT of money for a .2 ratio
change!! Have you thought about getting a used 7" with
the 4.3 ratio instead?? Why are you changing??

SLYDIT
Keep calm, Forum Moderator here.
Keep calm, Forum Moderator here.
Posts: 1610
Joined: Sun May 21, 2006 6:18 pm
Location: In the Garage.

Diff ratio compatibility

Post by SLYDIT » Sun Jul 13, 2003 12:00 pm

A lightweight steel flywheel (8 Pound) would probably
give you the same sort of pickup as the diff swap. For
around a grand you could get a flywheel from the
states and an ACT heavy duty clutch kit.
On miata.net there have been comparisons made between
the two diffs and theres not much in it at all.

Glenn


--- Gary Morrison <gm@paradise.net.nz> wrote: >
Perhaps the slight difference in gearing could be
made up with tyres that are slightly undersized... I
don't know if there is a fitting that would do it...


On Thu, 10 Jul 2003 05:37:04 +0100 (BST), glenn
roberts wrote:

$850 sounds like a LOT of money for a .2 ratio
change!! Have you thought about getting a used 7"
with
the 4.3 ratio instead?? Why are you changing??

________________________________________________________________________
[...]
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

PeterD

Diff ratio compatibility

Post by PeterD » Sun Jul 13, 2003 5:59 pm

Thanks Glen, flywheel is underway as well.

PeterD

SLYDIT
Keep calm, Forum Moderator here.
Keep calm, Forum Moderator here.
Posts: 1610
Joined: Sun May 21, 2006 6:18 pm
Location: In the Garage.

Diff ratio compatibility

Post by SLYDIT » Mon Jul 14, 2003 6:06 pm

Have you got a crew organised?? Im sure youd have no
shortage of MX5ers keen to help out. How are you
prepping the car and engine. etc what suspension etc
are you going to use?? cant wait to see a MX out there on the back roads.
Glenn "SLYDIT"
RED '90 TURBO.
SCARING PRIUS DRIVERS SINCE 2002

PeterD

Diff ratio compatibility

Post by PeterD » Mon Jul 14, 2003 7:24 pm

Thanks for the encouragement Glenn. Planning on entering the Targa in
stock class, so only genuine Mazda parts available for that model.

Also looking for original 1.8 air box from air meter back. Can trade K&N
unit. More power on Dyno, but outside stock specs for class.

Proposed build:
93 S-Spec
Last oversize pistons on way from Japan
Lightened flywheel
Head skim
Custom made headers and exhaust
4.3:1 Diff

Had it on the Dyno last weekend as a benchmark 104.6/416

Back on again this Saturday after exhaust fitting.

My web site should be up soon
http://homepages.paradise.net.nz/peter.dixon/

May take U up on the crew, and a place to stay! (just kidding)

Rgds

PeterD

lou Girardin

Diff ratio compatibility

Post by lou Girardin » Tue Jul 15, 2003 8:20 am

Sorry this is late, I've been away. I think the Torsen or open 4.3 diff is
standard on the M2's with 16" wheels and 5 speed.

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