LSD. Essential?

I’m considering an ND2 RF as a daily.
My preference these days is for automatic, partly as I have a horrible urban commute of 8 miles in each direction 3 or 4 days a week (23 sets of lights!) partly as modern torque converter autos are so good (coming from ZF8 BMW) and can be controlled manually with no computer interference.
The auto ND does not have an LSD which concerns me a little, so my question is: How essential are they on the MX5, purely road use?
Look forward to peoples thoughts.

We had a thread up somewhere about this same subject. The general consensus was, don’t get hung up about having an LSD or not, the driving pleasure will be much the same in an MX-5.

BTW I know nowt about the finer details of LSD"s.:roll_eyes:

I would say that an LSD is really only relevant if you do hard cornering. Generally you will not notice much of a difference in everyday use.

If you were on a track, or really go for it on the road an LSD would be ideal, however, you will get more out of the auto as a daily driver than you will lose from not having an LSD

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I’m not convinced the LSD makes my ND more pleasant, my perception is you feel a weird kick from it when it acts where in a 1.5 it’s a more progressive slide. In either case it’s due to excessive cornering speeed for the conditions. My MX-5 is a welcome relief after 20 years of autos, great in traffic but not an active choice I made.
Whatever you decide, Make sure you test an MX-5 with auto. Mine were all very different, ironically the ancient 3-speed sludgematics were much more pleasant to drive due to their predictable simple nature, whereas modern ones have given heartstopping moments like refusing to kickdown when overtaking because the gearbox decided you wanted to drive economically whereas you actually had been stuck for miles behind some duffer; or that you’d like to pull out onto a roundabout in neutral because without a hydraulic torque converter it does not have any way of slipping the drive system between ratios.

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Orange, I think you’re referring to DCT/DSG double clutch gearboxes, which are universally dreadful IMO.
The mx uses a 6 speed torque converter box, and from what I’ve read is pretty basic, but importantly when in manual mode will not change gear unless you tell it to, unlike many other autos.
My own thoughts are that with under 200hp, little torque, good suspension and light weight an lsd shouldn’t be strictly necessary.
Current car is 400hp, 500ft lbs, so lsd is definitely necessary!

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Having had both, an ND1 1.5l without, and an ND2 2.0l with, I would say “No”. In normal road driving conditions I have found no advantages or dis-advantages with either, so unless you use your car for “track day” racing, I don’t think LSD essential at all. I’m no expert, just a “day to day” driver.

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Yes I would agree. I think basically if you don’t know if you need one or not it probably means that you don’t. If you start sliding in a car with an open diff it will try to make you stop sliding without any drama whereas a car with a lsd is more for someone who is intending for the slide to happen and the lsd will make it easy to control. If you don’t want your car slide then the open diff can be considered an advantage.
Also bear in mind that if you get used to the car with an open diff and want to progress its not a big deal to make a change later.

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It is a big change though, as the ratio on the manual diff is much longer than the auto. Sixth gear is direct (1-1) on the manual car, fourth on the auto is direct, so if changing the diff I’d have to make sure there’s enough torque at low revs to pull a really long 5th and 6th gear in the auto. Physically changing the diff housing is easy.
It would make for a good motorway cruiser though, not really it’s natural habitat!

Thanks Overdrive for clarifying LSD and Mx auto box. Agree about Mx on motorway, though I’m sure even the Mazda auto box can’t be as short as my old Pug Rallye which was screaming away at 4000rpm in top at 70mph!

I’ve had years of big diesels, and my current petrol is at <2k rpm at 80.
As people have said, I really need to drive a manual and auto and make a decision. Roll on the end of lockdown :grin:.
Appreciate everyone’s input.

These are the MPH/1000RPM for the two gear boxes using 205/45 R17 tyres. If you need any more info just ask and I will attempt to oblige.

This is for the MX5 ND Automatic:

MPH per Gear
1000 RPM
33.6 6th
27.4 5th
19.6 4th
13.9 3rd
9.5 2nd
5.5 1st
6.2 Reverse

This is for the MX5 ND Manual:

MPH per Gear
1000 RPM
24.5 6th
19.0 5th
15.3 4th
12.0 3rd
8.2 2nd
4.8 1st
5.2 Reverse


I have had an ND 1.5 (no LSD) and currently have an ND2 2.0 with LSD, on the mountain twisties you notice the extra traction the LSD brings to the party particularly when you add power coming out of the corner.

Essential, no, nice to have, yes.


SWMBO’s 2002 Sport LSD really only comes into it’s own if pulling smartly out of wet weather junctions & roundabouts. Safer. Bar that, pretty much redundant.
My '93 auto ( open diff) does need a bit of throttle feathering when the torque converter dumps it though…which just means I wait for a slower exiting. Even with good Rainsports fitted…it’ll still squeal the nearside rear on smooth tarmac.

Malc, are your calculations allowing for the different final drive ratios?
If so it should work ok, just, but may need a downshift going fast uphill. Or a turbocharger :slightly_smiling_face:.
Thanks, by the way.

Hi O,
Yes is the simple answer. I have constructed a spread sheet that does all the sums, you just need the final drive and gear ratios along with the circumference of the tyre and it spits out the answers. The extraction below is for the manual and shows speeds in MPH for the 6 forward and reverse gears.
As you can see 3rd maxes out at 90mph so not a bad overtaking gear!!!

Maximum Maximum Maximum
Torque Power Revs
4000 7000 7500
98 171 183
76 133 143
61 107 115
48 84 90
33 57 61
19 34 36
21 36 39


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Would you mind doing the sums for the automatic, with the standard diff as well as the manual lsd one please?
It would save me a lot of calculator time. I can supply the numbers if it helps, although thinking about it you probably have access to them.
I can then factor in the available torque at various revs.
I’ve a feeling it’ll be just about useable, as long as changing up in the lower gears doesn’t result in dropping completely out of the power, with 5th and 6th being pretty much left for pottering about.

Here you go----

Maximum Maximum Maximum
Torque Power Revs
4000 7000 7500
134 235 252
110 192 206
78 137 147
56 98 104
38 66 71
22 39 41
25 43 46


Wow everyone will be looking to get an auto if it does 252mph! :joy:

M62 Windy Hill to Brighouse perhaps, it looks long and steep enough!!! Any volunteers???
The gearing would suggest that they will drive in a completely different way to each other. The auto is certainly ‘long legged’.

Those figures are for an auto with a manual LSD equipped diff. As standard both auto and manual are similarly geared, (engine revs to road wheel speed) as although in the auto 6th gear ratio is less than 1:1, (4th is 1:1) the auto diff is shorter to compensate. (3.6)
The manual is 1:1 in 6th, and uses a 2.8 diff ratio.
So, an auto with a manual diff will be very long geared compared to standard versions of either.
Is it worth it to gain an lsd? I’ll have to test drive both the auto and manual, make a decision to buy one, probably auto, run it for a while and see what I think.
As long as I can pick up a used manual diff for sensible money it’s easy to swap them and worth trying.
Hopefully the speedo reads from the abs sensors and isn’t related to gearbox. That needs looking into.