How does a torsen diff know if the tires are spinning or simply moving at different speeds? Doesn't the speed difference lock up the two axels and actually shunt more power to the inside wheel as it sees the outer, faster rotating wheel, as spinning?

SH-AWD actively puts more power to the outer wheel, but it seems to me that a Torsen actually applies power to the inner wheel on accelerated cornering.

 

TORque SENsing. Not SPEed SENsing.

 

Yes, but look at how the torque is sensed by the wheel rotation differences.

 

Very little information out there that intuitively demonstrates how a Torsen diff really works. And unfortunately the best one is in French...

Torsen does not lock-up the wheels. It actually transfers more torque to the outside wheel, since it has more traction, which is desired. How does it do that? It is related to the mechanics of the internals. I needed to study various diagrams to convince myself (Type-I is easier to understand than Type-II). The way the gear angles are set up somehow creates more resistance between the input and output for the wheel with better traction (less free spinning), and that resistance enables that wheel to receive more torque than the other.

Unlike the clutch-type LSD's, the resistance is not caused by friction, but by the way the gear angles are setup, which also determines the torque bias ratio (how much torque difference can occur). It's pure genius.

CKit, you said Torsen diff's have advantages and disadvantages. Aside from the wheel hop issue (no torque causing wheel spin), are there any other disadvantages? What are the advantages based on your experience (besides it being pretty much maintenance-free)?

 

Don't you mean "wheel spin causing no torque?"

I'm not an expert on these things and I don't want to overspeak my knowledge.

I like our Torsen on our daily driven CR.

I like our clutch-type diff on our "racing" AP1.

With STR class allowing clutch-type LSDs, I'd imagine we'll get a lot of expert knowledge in the next few years.