LSD or not LSD?

Bevan · Postby **Bevan** » Mon May 22, 2006 2:49 pm

No, it definitely won't have an LSD. I don't even think the LE models of 97 had one... did they?

EGG80X · Postby **EGG80X** » Mon May 22, 2006 3:57 pm

u can do it on a dirt road if you're worry about tyres

kitkat · Postby **kitkat** » Mon May 22, 2006 4:27 pm

revving it and dropping the clutch wont tell you anything. I have a 89' 318i open diff and i could make it drop double lines everytime like that without fail.

Maybe try driving in a circle then putting full power down... if it has LSD it should spin both wheels making you do donuts... if open only the inside will spin.

StanTheMan · Postby **StanTheMan** » Mon May 22, 2006 5:03 pm

http://www.miata.net/garage/vlsd.html

kita is right. the rest of you are all wrong

Moggy · Postby **Moggy** » Mon May 22, 2006 6:13 pm

I've been trying to work out if my '89 mx has an lsd or not. It has a fair bit of power at 125rwkw and I can assure you that if I drove in a circle and put full power down I would lose traction in both rears in about 0.01 of a second. Likewise if you are going around a gentle corner and put in anything over half throttle the rear snaps out nicely (in the dry). But is this due to the power or the power and the diff?

My car has been on the road with said power for over two months and the diff has not shown a sign of breaking. I haven't done any burnouts as I don't feel the need but I drive in a fairly spirited fashion fairly often. No noises or lurching with power changes. I jacked the rear up and turned the wheels - in gear the wheels turn in opposite directions and in neutral they turn in the same direction...

Anyone know whether my diff is open or not from this info?

kitkat · Postby **kitkat** » Mon May 22, 2006 6:47 pm

ive also been trying to figure if ours is open or LSD, best way i think to find out is to open it up!!! so i be doing that very soon.

Unless anyone knows if you have both rears up and you turn one will the otherone spin in the opposite direction like an open diff or will it spin the same with an LSD, or will it not matter because there is no pressure?

Mr_Q · Postby **Mr_Q** » Mon May 22, 2006 7:01 pm

kitkat wrote:Unless anyone knows if you have both rears up and you turn one will the otherone spin in the opposite direction like an open diff or will it spin the same with an LSD, or will it not matter because there is no pressure?

I'm not sure that will help either. If I do that - spin one wheel by hand - the other wheel does nothing.

kitkat · Postby **kitkat** » Mon May 22, 2006 7:19 pm

hmm maybe its meant to do nothing with an LSD then.

I thought with an open diff if you spin one wheel the other wheel will spin the opposite direction.

SileNceR · Postby **SileNceR** » Mon May 22, 2006 7:20 pm

do the LSD's use LSD fluid? If so it should be marked on the filler bolt of the diff... that's how you tell with Falcon's and Commodores at least.... lol

Casey · Postby **Casey** » Mon May 22, 2006 8:57 pm

Bevan wrote:No, it definitely won't have an LSD. I don't even think the LE models of 97 had one... did they?

No Aust delivered '97's should have one from factory - I couldn't get one fitted as an factory option for love or money when I bought mine. Nothing to say its had one fitted afterwards of course.

kitkat wrote:hmm maybe its meant to do nothing with an LSD then.

I thought with an open diff if you spin one wheel the other wheel will spin the opposite direction.

This test doesn't work with TorSens.

bigdog · Postby **bigdog** » Mon May 22, 2006 8:59 pm

http://www.miata.net/garage/diffguide/index.html

this is guide to which diff is which on the big forum - might help.

Moggy · Postby **Moggy** » Mon May 22, 2006 10:28 pm

Thankyou bigdog!

All answers are on that page. I will summarise...

This is a 1.6 open diff with a smooth case:

And this is a 1.6 viscous LSD (torsen) finned case from the right:

And left:

You can see the way to tell the difference is by the tangs on the stub shaft flange where the half shafts bolt in. The open diffs have eight regular tangs (four with studs) on both sides while the torsens have different tangs on the left and right shaped as circled above.

It turns out I have a smooth case torsen which surprises me slightly as my car was one of the first Eunos Roadsters made (July '89, #100225) and I thought that all the first mx5's had open diffs...

Cool...

StanTheMan · Postby **StanTheMan** » Mon May 22, 2006 10:32 pm

so every one just ignored my post.... :cry:

Moggy · Postby **Moggy** » Mon May 22, 2006 10:39 pm

And I just realised that the above post (edit: my above post, I mean) is no help whatsoever to the original poster, who has a 1.8, and is currently wondering why their thread got hijacked... :oops:

The link does show both open and torsen 1.8 diffs but doesn't point out any external differences, nor did I notice any. :roll:

Moggy · Postby **Moggy** » Mon May 22, 2006 10:52 pm

StanTheMan wrote:so every one just ignored my post....

I didn't.

But it said this:

"(Q) How do I tell if I have a Limited Slip differential in my 1990-1993 Miata?

(A) You can't. There are no external markings on the housing to indicate a limited slip (both open and VLSD use a yellow colored fill cap). You could call Mazda Customer Relations (800-222-5500) with your VIN and just ask if it originally came with your car."

However according to the other link (from miata.net as well) there are external differences between the 1.6 diffs...