3.91v lsd

[b3albakii]

Today a got an lsd from junk yard with this number 3.91V
What about it guys.
What is the difference between 3.91V and S3.91 ?

[lambo]

The 3.91v is a Viscous-Type LSD from an iX whereas the regular 3.91 is a Clutch-Type LSD from a regular E30.

[AndrewBird]

Which is preferred?

[b3albakii]

Which is preferred?

Yes this is what i want to ask

[lambo]

Which is preferred?

I would say clutch type because viscous diff's are typically less efficient.

[b3albakii]

So i got a bad choice ?

[Wanganstyle]

So i got a bad choice ?

honestly its good for a street car if in good shape.

Clutch type is more aggressive but it really depends on what you are doing with it; also the condition of the unit. Almost all of the used clutch units I tear down are melted; pretty much dead.

[lambo]

So i got a bad choice ?

Not necessarily. It's still better than an open diff. It's just that with sustained loads, I believe they start to lose their limited-slip properties and gradually become open diffs.

Someone correct me if I'm wrong, though.

[Wanganstyle]

Not neccesarilly. It's still better than an open diff. It's just that with sustained loads, I believe they start to lose their limited-slip properties and gradually become open diffs.

Someone correct me if I'm wrong, though.

yes, if the item has been seriously stressed it will not function as intended - i.e. the VLSD in my miata only locks up when seriously heated up or in the air on the lift.

I'd really like to have a fresh clutch LSD in my car but am not able to justify the OS Giken I would like; it costs more than the miata....

[b3albakii]

honestly its good for a street car if in good shape.

Clutch type is more aggressive but it really depends on what you are doing with it; also the condition of the unit. Almost all of the used clutch units I tear down are melted; pretty much dead.

Well ... Its really good like new
Dose it called an lsd ?
My engine is M50

[Wanganstyle]

Test the lock up breakaway, if it will hold the torque then use it :)

[strang3majik]

As a viscous clutched diff goes bad they actually lock harder to the point it'll feel like a locker around corners chirping tires and such.

Common problem in viscous clutch style transfer cases is they'll lock in 50/50 4wd and they'll actually bind up in turns.

When they work they're more comfortable though as they only lock posi when needed allowing all the benefits of an open and a lsd diff.


In the snow they'll only spin one wheel though.

[Robotin]

i also thought the VLSD's were better because they are a higher locking % because they are meant for AWD.

[LuckyHenriksen]

I have a few V4.10s and V3.91s if anyone needs one ;)

[nando]

As a viscous clutched diff goes bad they actually lock harder to the point it'll feel like a locker around corners chirping tires and such.

Common problem in viscous clutch style transfer cases is they'll lock in 50/50 4wd and they'll actually bind up in turns.

When they work they're more comfortable though as they only lock posi when needed allowing all the benefits of an open and a lsd diff.


In the snow they'll only spin one wheel though.

What? No.

Also, they usually fail open on ix's, although rear vc failures are fairly rare.

I've never noticed the vc's losing effectiveness in extended track driving either.