Newbie to mx5's and I am a bit confused

[jakdh]

First of all, hi! This website is incredible and I am so glad to find such a wealth of knowledge about these cars. My main question is I don't know what type of mx5 nb8a mine is purely because of these reasons and would love to find out what parts are in it; I have read that a lot of nb's have open diffs from stock and one way to tell if mine has an LSD is to do a skid which I have done many so far and there is always 11's on the road, this is the main question on my mind purely because as far as i understand only the 10ae's have them from stock? and on the door sticker it says its a special edition and I am soo lost by this. I know it is a jap spec from vin checking on websites but this is the thing, every time I checked it all that was said is that it's a jap spec. I am calling the mazda dealership where it was bought from and will ask them for info on the car but has anyone heard or seen anything like this?? All I want to know is if its anything special and most importantly if it has a LSD so I don't have to upgrade that bit until it dies oh and I also had another post about my car stalling but how do I delete it as that issue has been and gone for ages now. Any information would help because I can only hope the mazda dealership that it was bought from according to the Mazda service records that came with the car still has info on my car.

[ManiacLachy]

Welcome.

It's a bit hard to tell what your car is exactly without info on the year, or any special badging around it, some special models were in a special colour so that might help too. Post some pictures It's likely your car didn't come fromt the factory with an LSD, but that doesn't mean one wasn't installed later.

You can't delete threads, so just update your stall thread with a post saying problem solved. Maybe say how it was solved, what the issue was, etc so if someone else has a similar problem and they come across your thread they can get some handy info.

Also, don't do skids in the streets

[Charlie Brown]

Welcome to MX5's. I know you'll love it.

I doubt that your dealer will have a clue if it has a LSD. I'd say there's a 99.9% chance that it hasn't got one, which doesn't matter even if you intend to do some track work as the class you’d be in wouldn’t allow LSD’s anyway.

Have fun.

[93_Clubman]

...and on the door sticker it says its a special edition and I am soo lost by this.

All MX5 NA & NB door jam stickers have 'special edition' as a category on them, but they are only a special edition when there's actually information in the space immediately below where it says 'special edition'.

...I know it is a jap spec from vin checking on websites but this is the thing, every time I checked it all that was said is that it's a jap spec. I am calling the mazda dealership where it was bought from and will ask them for info on the car but has anyone heard or seen anything like this??
I can only hope the mazda dealership that it was bought from according to the Mazda service records that came with the car still has info on my car.

If the VIN starts with JM0NB30P1 then it was an Aust Domestic Market MX5 NB8A (ie 1998-2000), but if the VIN contains NB8CE then it's a Japanese Domestic Market Eunos Roadster & subsequently been imported from Japan after initial delivery.

[jakdh]

Ok that helps a lot, its definitely an Aus spec then and its good to know that its not anything special as well. I just dont really understand how the open difs work because iv been in lsd cars, mine feels very similar with both wheels always spinning off the line and while sideways it spins both directions just as easily but I thought an open dif in essence is 1 wheel drive?? as well as the 11 tire marks Oh and in reference to not doing it on the road, I only do it in my driveway, the true Australian way haha but yeah that's great and thanks for the information. Maybe it is one wheel drive or someone put an lsd in it before I got it.

[hks_kansei]

Open diffs are two wheel drive, however, when there is a difference in grip the wheel with less grip will slip first.

The simplest way to test for an LSD is to exagerrate the difference, so park with one rear wheel on dry bitumen, and the other on dirt/wetgrass. Let the clutch out (not enough to spin on the bitumen)

If the car sits still with the grass wheel spinning, it's an open diff.
If it launches with both wheel spinning, or neither, it's an LSD.

The Viscous LSDs are all fairly worn by now, so will likely act as an open diff.

[22Silver]

In regular driving open diff/LSD will feel similar.
You'll only notice the difference if you are tearing up corners or driving on gravel/dirt/wet roads.

Most likely has an open diff. Clubman versions (I believe) all come with an LSD, even the old NA clubsport/clubman, but they tend not to come with aircon and such.
(Based on experience with my fathers NA clubman/sport (clubman or clubsport, which is it???) which had an LSD, a 1.6L engine, and no aircon or power windows (maybe power windows). It was white (and is still white, but highly modified, we saw it at a Thursday night clubmeet in Victoria!, the new owner has done it great justice.)

Either way, don't worry if you dont have an LSD, you wont "need" it until you have mad cornering skillz, an even then, there's probably other things you would notice (as an upgrade) more, in terms of improvement in track time per dollar spent.
In terms of "sick skidz" per dollar spent, it goes;
Stiff rear sway bar > everything else.
Don't stiffen the rear sway bar unless you highly balance the set up...

Please post pictures!!!

[jakdh]

Awesome I am so glad someone explained that whole lsd thing, I was full thinking it was like a bombadore where only one wheel provides power and when you do lose traction only the same wheel spins. Makes me happy that I wont have to change it straight away but I did do the grass thing with one wheel on the concrete this morning and one wheel was spinning but the other wheel on the pavement was not spinning but as I took it of the clutch it basically had one wheel spinning on the grass and the other one was pulling me forward on the concrete but still feels like its open and not an lsd. If I where to go turbo is it a high priority sort of thing to change to a lsd?? for strength or something?? Also what did you want pictures of?? the car??

Thanks for everyone's help on this and in my other post, not even mx5 mania could explain that diff stuff and the stalling issues in my other thread were pretty much fixed because of people on this forum helping me out.

Greatly appreciated!

[hks_kansei]

Open diffs aren't one wheel drive, they are still two wheel drive.

The difference is that an open diff will always transfer more power to the wheel with least resistance.
Commodores are still 2wd, but the reason they spin one wheel a lot more easily than an open diff MX5 is a combination of more torque (easier to break traction) and sh*t suspension (more weight transfer off a wheel, ie: less grip)

There's other factors, such as the driveshaft length etc that can add to one wheel breaking traction more often too.



The main types of diffs are:

Open
Viscous LSD
Clutch LSD
Torsen LSD
Spool LSD
(there's a few more, but the list above is what applies to MX5s)

The open diff is standard on Aussie MX5s, it provides no LSD action and will mean that in a hard corner the inside wheel may spin (less grip due to weight transfer)

The viscous LSD works by the centre of the diff containing a thick fluid that causes the wheel opposite the spinning wheel to also spin a little. Not too unlike an auto gearbox in theory.
The Viscous LSD isn't a particularly good LSD, as the fluid degrades over time.

The Clutch LSD operates via small cams inside the centre that force friction plates against one another, when a clutch LSD grabs, it locks both wheels together, meaning they will both spin at the same speed regardless of grip. (these diffs can be setup as to how hard, and under what conditions they clutches grab)

The Torsen LSD is that Mazda used on the NA clubman and the NBs with the optional LSD. It operates via internal gearing and will multiply torque to the wheel with more grip. Where an open diff will allow a situation where a wheel can have 100% torque, and the other zero, a clutchpack will always lock to 50% each. A Torsen will transfer a set rate from the slipping wheel to the grippy wheel. I think the MX5 uses a 3:1 rate, so if a wheel slips it transfers 3 times the torque to the grippy wheel. Torsens are great for a road car, but hard to explain without having seen inside one.

Spool LSDs aren't really an LSD, they're more a No slip diff. Basically a spool is a welded diff (some companies sell spool centres which are specially made centres with no gears) a Spool diff will ALWAYS power each wheel 50/50, regardless of grip. You really don't want one of these for most cars, they tend to make it handle pretty odd.

[smy0003]

An LSD won't increase the strength of your diff, the crown and pinion gears are the things that blow up. But since you have an NB it's unlikely that you'll ever break the diff.

An open diff is an open diff regardless of what car it is on. It is 2WD up until one wheel starts to slip, then the power follows the path of least resistance, spinning the slipping wheel and sending no power to the wheel with more grip.

You're most likely leaving 11's on your driveway because both your rear wheels are losing grip at the same time. Therefore the power is still being sent through both rear wheels. In a corner this will not be the case, and you'll be spinning the unloaded wheel.

You can swap your diff for a factory mx5 torsen LSD assembly fairly easily, or you can use a clutch-pack LSD centre. It depends on what sort of driving you are doing, if you want to go drifting, how much money you have and blah blah blah.

There's heaps of information out there about MX5 diff choices, have a google around.

And post pictures because we like pictures

[ManiacLachy]

Who else with a torsen has been stuck going up a driveway with one rear wheel in the air?

Whats 0 (torque on the wheel in the air) x 3 (torsen multiplier)?

That's right, the grounded wheel get's no power!

[hks_kansei]

Who else with a torsen has been stuck going up a driveway with one rear wheel in the air?

Whats 0 (torque on the wheel in the air) x 3 (torsen multiplier)?

That's right, the grounded wheel get's no power!

Pull the handbrake up a bit, the caliper will drag and give enough load to multiply into grounded wheel movement.

I've never had a driveway issue though, never needed to use a driveway steep enough to lift a wheel.
That, and my Torsen is still pretty tight and has some pre-load. (the cone washers in them wear out and they lose pre-load over time, you can shim them up for even more pre-load if you want)

note: my T2 came from a low km car, and I had it rebuilt before putting it in my car

[speed]

An LSD won't increase the strength of your diff, the crown and pinion gears are the things that break.

You're most likely leaving 11's on your driveway because both your rear wheels are losing grip at the same time. Therefore the power is still being sent through both rear wheels. In a corner this will not be the case, and you'll be spinning the unloaded wheel.

This.

If you are going to track it then get a lsd.
If not, what you have is fine for the road and as you've already discovered, both wheels hook up most of the time in a straight line.



Sent from my iPhone using Tapatalk

[ManiacLachy]

Who else with a torsen has been stuck going up a driveway with one rear wheel in the air?

Whats 0 (torque on the wheel in the air) x 3 (torsen multiplier)?

That's right, the grounded wheel get's no power!

Pull the handbrake up a bit, the caliper will drag and give enough load to multiply into grounded wheel movement.

I will give this a try next time! Happened to me twice so far.