Which MX5 diff
Padstar - 2/7/12 at 09:21 PM
Hi I have read on here that the latter LSD unit is better than that fitted on the older cars. The diff I have from what I understand is from the year
where they changed from one to tother. How do I know which model/unit I have and which is better?
adithorp - 2/7/12 at 09:58 PM
I found THIS GUIDE when searching for answers a while ago.
Padstar - 3/7/12 at 07:10 AM
Thanks for the link great description of each model.
At first glance it looks like I have the earlier VLSD model from the 1.6. Will have a much closer look over the weekend.
Which is classed as the better option? It is likely to be used with a 1.8 duratec engine.
[Edited on 3/7/12 by Padstar]
pewe - 3/7/12 at 09:08 AM
IIRC the early LSDs were viscous and didn't last well.
Later Torsen ones are mechanical and longer lasting.
To fit to an early car you will need the propshaft and push-in drive shafts from a 1.8.
Identify these later diffs by looking through the driveshaft holes and you'll be able to see all the way through.
Be aware that most (if not all) Torsens are low geared, great for acceleration but a bit revvy on motorways (3750 @70mph on 15" wheels).
However in terms of performance and extra grip well worth fitting (ask me how I know!).
And before you ask - the later 6 speed box doesn't give much advantage in terms of gearing.
Contact Nick of Skuzzle Motorsport all round good guy and very helpful.
HTH.
Cheers, Pewe10 
Padstar - 1/8/12 at 12:54 PM
Is a diff from the current model MX5 the best option? Would a low mileage 2007 unit be worth investing in?
Also are the drive shafts standard units from the donor or do you have to have made/modified to suit Haynes use?
chillis - 1/8/12 at 02:06 PM
quote:
Originally posted by pewe
IIRC the early LSDs were viscous and didn't last well.
Later Torsen ones are mechanical and longer lasting.
To fit to an early car you will need the propshaft and push-in drive shafts from a 1.8.
Identify these later diffs by looking through the driveshaft holes and you'll be able to see all the way through.
Be aware that most (if not all) Torsens are low geared, great for acceleration but a bit revvy on motorways (3750 @70mph on 15" wheels).
However in terms of performance and extra grip well worth fitting (ask me how I know!).
And before you ask - the later 6 speed box doesn't give much advantage in terms of gearing.
Contact Nick of Skuzzle Motorsport all round good guy and very helpful.
HTH.
Cheers, Pewe10
"the early LSDs were viscous and didn't last well. " Mine is still working after nearly 200000miles. Their lack of function is often
confused with the way they function. They dont lock instantly.
Padstar - 1/8/12 at 02:17 PM
So that would be a yes then unless u r a big fan of the original viscous type.
Just checking that the Torsten ones run right up to the current model.
Sorry to keep going over old ground, I just want to get it right.
DH2 - 1/8/12 at 04:34 PM
quote:
Originally posted by Padstar
So that would be a yes then unless u r a big fan of the original viscous type.
Just checking that the Torsten ones run right up to the current model.
Sorry to keep going over old ground, I just want to get it right.
Diff used in the Mk3 2006-on is a completely different casing to the previous models, as the Mk3 rear end is derive from the RX8.
DH2
Padstar - 1/8/12 at 05:52 PM
So will it not suite the standard MX5 Haynes chasis?
DH2 - 1/8/12 at 07:50 PM
quote:
Originally posted by Padstar
So will it not suite the standard MX5 Haynes chasis?
No idea, but would guess that the chassis has been designed around the earlier MX5 as a donor?
DH2
indykid - 1/8/12 at 10:51 PM
You need a diff from a 1.8 if 94-97(1.8 mk1), or any model from 98-04 (the 1.6 and 1.8 got the same diff from then on). A mk3 diff is completely
different and even if it fits, you're paying a hefty whack for a less available part.
You can identify a 7" diff by the rubber damper behind the pinion flange. The 7" diff body is longer than the 6.5" so you need a
shorter prop if fitting to an mx5, but if in a locost, I presume the prop will be modded anyway. Early mk1 7" diffs came with bolt on halfshafts.
Later models came with single piece push in half shafts.
Early 1.6 diffs were 4.3:1. All mk1 1.8 diffs were 4.1:1, either open or type 1 torsen (apart from the RS ltd which got a 4.3:1 CW&P set on torsen
guts)
Mk2 and mk2.5 5 speeds are 4.1:1. The 6 speeds got 3.9:1 and 3.6:1 diffs. These are type 2 torsens if LSD.
The mk2.5 sport got a tochigi fuji diff - a combination of clutch and torsen diff, but the clutch plates are fragile and a number of people have
reported the plates breaking up.
Padstar - 9/9/12 at 08:59 AM
I have been looking around for a bit now since my last post and have located a diff from a 2003 1.6 manual 5 speed MX5. Is this the unit I should be
getting? Will this mate with the engine/gearbox I have from the 99 donor car without any problems.
Out of interest and in the spirit of locost what is a reasonable price for such a unit?
chillis - 9/9/12 at 10:04 AM
quote:
Originally posted by Padstar
I have been looking around for a bit now since my last post and have located a diff from a 2003 1.6 manual 5 speed MX5. Is this the unit I should be
getting? Will this mate with the engine/gearbox I have from the 99 donor car without any problems.
Out of interest and in the spirit of locost what is a reasonable price for such a unit?
Have you confirmed it is an LSD? LSD's are NOT repeat NOT a standard fitment on any MX5 except ltd ed's. Many were specified as options but
you cannot assume it has an LSD - you must check using the guide posted at the top of the thread.
indykid - 9/9/12 at 07:45 PM
quote:
Originally posted by Padstar
Out of interest and in the spirit of locost what is a reasonable price for such a unit?
If it's open, they're hard to give away. I sold an open 1.8 diff for £40 and thought I'd got pretty good money for it. A torsen on the
other hand will sell all day long for £250-300.
There's a breaker on mx5nutz.com called junk yard dog. He's the go to guy for reasonably priced mx5 bits.
Padstar - 10/9/12 at 04:46 PM
Are they all the same casement size etc. if so then maybe I will just install the one I have from my donor and then change when complete and
roadworthy 
if I don't like it.
I guess they are relatively easy to change over along with drive shafts? Do the mx5 rear hubs take drive shafts for both type diff?
indykid - 10/9/12 at 10:33 PM
The 1.6 case has a shorter nose because of the smaller crown wheel, so needs a longer prop.
The chassis mounts are identical on either diff though.
Either halfshafts fit the hubs, but they can be a pig to separate. (10 ton press and heat - lots of heat)