tecknomage

The dif that I am looking at getting a s4 the car has about 90k in miles on it its in the junk yard has front end damage

Not my car is a s4 vert I’ve heard that the s5 LSD's can have problems with the fluid braking down but I haven’t heard much about the s4's and if they have any problems I would imagine they would have ware and tare problems like the clutch that engages the transmission

The car that I’m looking at taking the LSD from is a 86 GXL and it looks like its in decent condition although the body damage is abnormal it looks like the car gave out and the fender got pushed up maybe the car bottomed out but how am I to know its in a junk yard

Any knowledge will be gladly accepted

Impreza2RX7

From what Ive heard, the Viscous LSDs are alot better than the clutch type, but I have no evidence from personal experience..

Turbonut

iTrader: (1)

Clutch Types LSD uses clutch packs that push against the spider gears of the rear end when one wheel starts to spin faster than the other. Clutch type LSDs are one of the best, as they have a very fast lockup , and can usually handle alot of power. Downside of a clutch-type LSD, is that over time the clutch packs can wear out, and not work very well.

Viscous LSD uses the rear end fluid to accomplish the same thing, by not letting one wheel spin faster than the other. The downside of this LSD, is that is is the slowest to react, because one wheel has to start spinning before the fluid LSD reacts and starts to work. Probably the worst LSD as far as performance is concerned, but will most likely last forever, they're not prone to wearing out or breaking.

Above courtesy of Rxmfn7. You can check:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/lsd-220100/

RX-Ben

Viscous is about the worst you can use for the above state reasons. I don't think a genuine race car would ever use a viscous type.

The clutch type is good and very robust, though needs rebuilds. The torsen type (FD diff) is smoother in operation, though not as stout, and doesn't require rebuilds.

RotaryEvolution

iTrader: (30)

off the line is where you want the wheels to work together, i would choose my clutch diff rather than a viscous.

tecknomage

kewl ty for the info

1987RX7guy

iTrader: (3)

S4. <-------period

Wanked_FC

iTrader: (1)

the s4 is bullet proof, the s5 will blow up if you try to drag launch with gobs of HP

rxspeed87

viscous was designed not really as a performance lsd but rather for all weather type driving I would say. mainly just to help keep the car able to move in the wet,snow
if your going to be doing road racing myself at least would go torsen though for straight line easily s4 clutch pack

tecknomage

i just dont wany to go off the road in the winter and i wanna have fun in the summer

Bigretardhead

clutch type, all the way. ever noticed how like all aftermarket LSD's are clutch type? because they're the best performance.

RotaryEvolution

iTrader: (30)

actually the best are lockers but they aren't technically considered LSD.
i had a beefy locker in my elcamino, it held up to some serious launches and unless you break them they won't slip, at least a decent one won't.

RotaryWeaponSE7EN

iTrader: (6)

cafcwest

I prefer clutch over viscious. People will answer however, you know those opinions....

I would like to point out this though:
All convertibles have a 3.9 rear end.

5 speed GXL is going to have a 4.1, an auto GXL a 3.9

If you pull the diff from the 5 speed car, grab the speed sensor from the tranny or your speedo will be off about 5%.

Bigretardhead

good point about the speedo gear.

oh, and with the lockers, they may allow you to launch well, but they'll screw with you when cornering.

RotaryEvolution

iTrader: (30)

that's why i will probably always have my clutch pack in my 7.

it all depends on how you drive, some people build em up for drag and others build them up for all around and yet others for sporty roads.

capn

well if you change the diff you can just change out the ring gear too wile your at it so you dont have to worry about your speed bein off. just put your old ring gear on it and then you'll be fine

and how much are s4 clutch lsd's going for these days? and is there an easy visual way to tell differences between the two?

tecknomage

one says LSD one dosent is the simplest way to put it i found this car in a junk yar i got fresh pickings looks to me like the owner rearended soem one and the car only had 90k in miles on it

question ware is the speed sensor on the tranny and how hard will it be to get off / how big ?

jspecracer7

Yes. When you pull the pumpkin cover off the gear will be to the left of the LSD. Look thru the hole in the center. If it has gears it's an S5. If it has clutch disks, it's an S4.

tecknomage

i know that hehe and i know its comming off a s4 86 GXL

i just need to know what the speed sensor looks like

andrew lohaus

to my kcowledge forumla 1 cars use viscous lsd's which was realy surprising too me. so they arent all bad. they probobly need them for the durability cus just imagine what one of those thing goes through. 800hp and missive traction i bet a clutch or torsen type couldnt hld up, but thats just a geuss.