now I need to search and see what all is needed,

Thank You

 

US FCs, at least. While it's unbelievably unlikely that the OP has it, the Infini IV did come with a Torsen IIRC.

 

is there a way to tell by looking at it? if it has Torsen r not?

 

get under and look to see if it had a tag on the drain plug or remnance of a tag. its hung underneath the drain plug like a washer would be if its there.

if its 100% stock, it will have a tag saying "Limited slip differnetial fluid only!"

 

Yeah, lift the rear end up, and spin the wheel on one side.

If the other spins the same direction, then you have a LSD.

If the other spins the opposite direction then you don't. You don't have a Torsen, you don't have a Clutch type, and you don't have a Viscouse... you don't have a LSD.

In 22 years of working on FC's most of the people that think they have a LSD, don't. Most think that they have the one special car that has it, but they don't.

Does your's have a Yellow LSD tag on the fill plug? If no, then you probably don't have one.

But jack the rear end up (the factory jack fits right on the jack point of the differential) and turn one wheel.

Unless you have a Turbo, I would be 99.9999 percent sure that you don't have a LSD on your 91 unless someone put one in aftermarket.

And the Torsen style differential was only available in either a 8 inch differential (and was only found on the 91 Infini IV, 92+ FD and the FE) or in a 7 inch differential (some Miata's). So if you don't have a 8 inch rear end (which only came on Turbo FC models) you probably don't have a Torsen style differential either as the swap to put a Torsen style Miata differential into a FC is not something that most non turbo FC owners can do or can afford to do.


But jack the rear end up (the factory jack fits right on the jack point of the differential) and turn one wheel. See for yourself.

And as a FYI: Pulling or twin burn outs just means that you have either a busted suspension or crappy tires and traction.

 

Or something broken in the rear.

 

Did I open a can of worms or what?

no Turbo, stock N/A.

I'll slide under her tomorrow after work.

and bty, I have 275/40/17's n the rear there Fuzion ZRi tires.

 

Nope, you just seem to think that you have something that you don't really have and despite all the good members telling you that you don't have one, you don't believe them.

 

its not that, I'm lost when it comes to 7's, just she is 100% stock and all the chevy's I had with lsd kick it sideways and this one does also.

plz don't take it the wrong way, if she don't have it I like to get it. and 3.90 gears.

I have learned a lot from my short time on this forum. and I hope to soak everything y'all say like a sponge.

I like to have a safe but fast 7 I can. on a budget..

 

oooo... cheap tires, maybe mark was right about the tire thing. Couldn't afford anything better?

 

that is called a lack of traction and poor rear end design

 

they came with the car. lol

I'm going to bed, going to look for a tag, or whats left of a tag after work.

Thank you for all the input

is 3.90 the way to go or stay with 4.11's?

I like all around low mid and top speed.

 

Depends on what you are trying to do.

Best top speed: 3.9
Best 0-60: 4.3
Good mix of both:4.1

 

the coupe came with 4.1, so I'm good there

 

If its a real lsd then you don't really know what's in there. I have a 4.30 in my diff, :P.

 

Best top speed? Probably not - top speed in the NA is not rev limited, but rather power limited. However the best fuel mileage is probably with the 3.9.

Now, I'm just waiting for the next question about premium fuel.

 

lol, yah, gas. Lets just nip this one in the bud now then. Your car was tuned on 87, so put 87 in it. You dont get more power from higher octane gas.

 

well..... I run mid gas... till the next fill up. I have 1/4 in her now.


I got pix on my diff, there is a tag around the fill hole.

<br>
is this a LSD from Birth? lol

 

looks like it. what they are saying about kicking sideways is true chevys have horrible rear end design especially camaros. but also i would like to state that the whole jack up the rear end and spin the tire trick works.....sorta. you have to make sure the car is in nuetral that is something people fail to state. if the car is in gear lsd or not the wheels will spin opposite directions. but with that tag there i would say it looks to definitely be a lsd. whether or not you have a special car.(which i highly doubt). i am pretty sure whether it was an available option on paper or not. if someone wanted it when they bought it new they could get it. my dad did buy his truck from the dealer he built it online with all the options he wanted including some that weren't listed and it was built exactly as he wanted from the nummi factory. lowered from the factory.

 

I seen the order papers, nothing about lsd. well the ladie I got it from was hot. just nice to know I have a lsd.

is there any way to see is its special...lol

 

In the middle bottom (jack point) of the differential, does it look like this:

l l



or like this

O

 

let me go see

 

 

That is a S4 differential then and not stock on a 91. It would be a clutch type LSD, with faster engagement than a S5 Viscous... and not a Torsen.

 

is that good or bad?

and how can I find out the gear ratio?