Welding Diff vs Spool Diff centre vs 1.5 way vs 4.3

[Jimmynb]

Okay, So, I want more predictable oversteer as the entire reason i bought my mx-5 was to learn to slide.

I have been doing research on diffs for a while now and i am still very confused as to what i am after.

Previously i have been told that welding a differential can damage more components than simply the differential and I do not want this to happen.

I have seen the spool diff centre available at mx-5 mania but i do not understand what it is or what it does and what it will damage. I have heard that it handles and feels essentially like a welded differential. i have had a car with a welded diff before and i didnt find it terrible but i dont remember exactly how bad it was.

I know that a 1.5 way diff locks on acceleration and partially locks on decelleration therefore this is a good option.

I have heard that a 4.3 way is a smart option but not really suitable for oversteer control.

Can someone please give me more insight as to what i am after for oversteer and control without damage to the car?

[beavis]

As a general guide and based on what i can judge from your post, the best diff for you is probably a 4.1:1 ratio, factory Torsen LSD.
(you have not mentioned what car you have, where you drive it, or what is done to it)

http://www.ebay.com.au/itm/Mazda-MX5-NA-NB-BP-1-8L-4-1-Torsen-1-Diff-complete-with-Housing-Used-Good-Cond-/282039341877?hash=item41aadad335:m:m6dBYm687OHv1Iv2pSMfX-w

[Jeo]

4.3 is a drive ratio, not a style of diff.

[rascal]

A diff has gears in it that turn to allow the wheels to turn at different speeds to allow easy cornering.

'Welding the diff' is welding these gears together so they can't turn, effectively making both axles turn at exactly the same speed, always .
Fitting a spool to a diff means removing the centre gears and replacing them with a single metal piece that also locks the wheels together .
Welded or spool achieves exactly the same result. Welding is permanent, as you can't unwed the gears, whereas a spool can be reversed by removing the spool and refitting the centre gears. Spool is technically the better option of the two. Note that Neither is road legal. You don't mention if this a road or track car.

A 1.5 way is a better idea than both the above as well as being road legal.

There is no such a thing as a 4.3way. Think you are confusing the diff ratio of 4.3 with the type of diff.

[Jimmynb]

Okay, so my nb8a is bone stock and is used as my daily. However my daily driving entails a lot of attempted sideways driving (sorry guys) on quiet roads with no people around.

As for the 4.3, i assume that 4.3 are only made in LSD. So essentially i mean an LSD.

1.5 is what i want most but i am struggling to find one.

[Magpie]

Having recently swapped from a torsen to a 2 way my comments maybe helpful.

2 way is a lot of fun once you get used to it, if the car starts to oversteer put the foot down and steer. HOWEVER, the 2 way resists turn in and requires the extensive use of trail braking. The amount of 'lock' can be controlled by the number of clutch plates. It is possible to change between 1, 1.5 and 2 way.

A torsen, if you lift a wheel acts like an open diff. A torsen requires some resistance to work hence care is needed to not lift a wheel.

A clutch pack diff can be a bit noisy when turning sharply, like in car parks.

If you want to drift then consider a 2 way, most people will suggest a 1.5 way for track. But, as mentioned to me if you can drive quickly on a track with a 2 way you can drive anything.

It comes down to what you want to do and what you can live with. I'm really starting to enjoy the 2 way on the track.

[Jimmynb]

Magpie:

Isn't a two way essentially the same as a welded or spool i.e. locks on accell and decell therefore always locked?

Also where did you find a 2 way clutch diff?

[Jeo]

Right. Start here then come back.
https://en.wikipedia.org/wiki/Limited-slip_differential

NA/NB MX5's came from the factory with Torsen or Viscous type lsd's. Aftermarket you can find clutch types.

None of these have anything to do with the final drive ratio. Yes, there were 4.3:1 open diffs.
Factory NA/NB's came with 3.6, 3.9, 4.1, and 4.3 final drive gearing. This means that tailshaft needs to rotate 3.6/3.9/4.1/4.3 times to turn the wheels once. Each ratio is basically a trade off of acceleration vs top speed. Miata.net has a good overview of what your factory based options are. If going aftermarket, you can get basically whatever final drive you want.


Ignore viscous.
Factory torsens are the most commonly suggested.
I wasn't a huge fan of the Mazdaspeed clutch pack I had in my NA, but had heard good things about them otherwise.
For maximum attack hardcore touge drift battle e-peen though, just weld it and be done. It will be a prick to drive normally, but provided you're sideways all the time it's all win anyway.

[The American]

Magpie:

Isn't a two way essentially the same as a welded or spool i.e. locks on accell and decell therefore always locked?

Also where did you find a 2 way clutch diff?

A spool or welding has zero 'give' to allow the differential to 'differentiate' the wheel speeds. This means the rear axle will alway try to make the car drive straight ahead when trying to turn normally - it will "push".

A 2-way does lock both ways, but it's not locked all the time and will allow some slip or difference in left/right wheel speed before the clutches engage.

Tbh, you can slide nicely with an open diff with some practice (I've got clips of my first mx5 open diff sliding somewhere), and a bit easier again with a Torsen. The effort of a spool or the cost of clutch pack diff (2, 1.5 or 1 way) may not be worth it unless you've got long term drifting plans (in which case, sell the mx5 and get a Silvia).

Welding is cheapest, but if you get sick of it, you'll have a junk diff nobody wants. Torsen would be next easiest and not to expensive. If you get one already in a pumpkin, you could swap it in yourself in a Saturday. An aftermarket clutch pack would be the most expensive option, or the longest wait for one to pop up for sale.

[Jimmynb]

Spool is sounding smart as its essentially a reversible welded diff. I will keep looking, I never want to sell my mx-5, and i will always want to slide but not necessarily together. I wouldnt mind the idea of buying a s chassis and having the mx-5 as the daily. So in the mean time spool diff centre sounds smart.

[rascal]

I wouldnt mind the idea of buying a s chassis and having the mx-5 as the daily.

This is your best idea yet....

[mx5002]

Probably cheaper and easier to weld up your original diff and just buy another open diff if you ever wanted to revert back to standard rather than opening up the diff and messing around with the gearsets.

Mx5's are great to slide in the wet but you won't be no drift king with a standard mx5 and a locked diff in the dry

[Magpie]

If your intention is to 'slide' on public streets then I'm not sure what advice can be given. Personally I would keep it on the track and use the streets for normal driving...

A welded diff is worse than a 2 way, as explained by others a 2 way diff has some 'give' in it whereas a welded diff has NONE.

Have a read of this, it finishes with Definitely read what I wrote very carefully. "If you dont have any formal training or competition experience nor do you plan on either the 2 way diff is the worst thing you can get. Stick with the 1 way or 1.5way diff."
http://forum.miata.net/vb/showpost.php?p=1660929&postcount=10

[hks_kansei]

Welding Diff
A welded diff is, as the name suggests, any diff where the centre had been welded together to essentially make it act as a single solid axle.
It will never slip, both wheels will always turn at the same speed regardless of surface.
Bad points, when you turn the wheels will try to spin at difference speeds. If the tyres are able to slip (crap tyres, or slippery surface) this isnt an issue, but if they dont slip it loads up the half shafts as they try and twist them. This can eventually lead to either a broken shaft, or shearing the splines off the axle.
Other issues can be the welds breaking if they arent done that well.
Welded diffs are only really useful for a car that rarely does tight turns, so basically track cars.

Spool Diff centre
essentially a spool is the same as a welded diff, except instead of welding up the centre you replace it with a "spool" centre, which is essentially just a cast block to hold axles and crown gear, it has no gears in it.
The advantage over a welded diff is the lighter weight.
It carries all the same downsides.

1.5 way
This references a clutch based diff centre which will only lock the wheels together under certain conditions.
A 1 way will only lock the wheels during acceleration, and will behave like an open diff during cruise, or deceleration in gear.
A 2 way will lock during acceleration, AND deceleration, and will only behave like an open diff during cruise (or other low load times, like rolling etc)
A 1.5 way locks during accel, and will half lock during deceleration (allowing some slip, but not as much as an open diff) personally, of the clutch diffs I think this is the best street one.


4.3
This references the crown and pinion ratio, or the final drive ratio of the car. It has nothing to do with LSD or not.
An easy explanation is that this is like the size of the rear sprocket on your bike, a bigger rear sprocket means you have more torque and acceleration but need to pedal a lot faster to get to speed.
A smaller sprocket lets you have more speed without pedalling so fast, but it's harder to get to speed.
The 4.3 ratio is stock for the NA6
4.1 for NB8A
3.9 for NB8A 10AE
3.6 for NB8B
All are able to be installed/swapped to get the ratio you want, except for the NA6 diffs which are a different size.


Torsens
The factory LSD on the CLubman and later, a fer different versions exist but they operate by using many internal gears to transmit power to the side that needs it.
Great LSD, but not as predictable for drifting.


Viscous
OEM LSD option on the NA, works by having a centre of thick fluid which encourages each wheels to resist changes in speed compared to each other.
Not the best, and in my opionion not really an LSD, more a slow to react open diff.
More so these days since on many the fluid has started to degrade and doesnt work a swell.

[Jimmynb]

As i said a clutch type LSD is my preference. HOWEVER, I cannot find one anywhere. If anyone can give me insight as to where to get one I will enquire about it.

Second best seems to be to either buy the spool diff centre or buy another open diff and weld it therefore i can reverse it eventually.

Having spoken to many people being both mx-5 owners, drifters and essentially bro-scientists, and from personal experience with a ke-70 I know that if a car has enough power to do a standstill burnout then your car can drift with a diff, a handbrake and a clutch.

The s-chassis isn't exactly an option at this point as I am not willing to part with the funds necessary for two cars. Also, I have been looking for s-chassis but havent found a deal that I find good enough to part with my mx-5. Mx-5 is too good a car to let go of. Imagine having a roof, eww. If i found an amazing deal on an s-chassis I would take it, however my perspective on an amazing deal is unrealistic. Therefore I am looking for some way of sliding in the mean time.

As for all concerned with the open road aspect, it is more so closed/empty car parks and wide open roads away from people, traffic, and houses. I understand your concern and judgement and I invite it, however it is what makes me happy. Therefore I am willing to knowingly take the risk. I take all precautions to minimise the risk while still choosing to partake in the activity. I hope that gives some sort of insight into the reasoning and choice.