This is something I've pondered for a while, Weismann's famous (in the late sixties/seventies/eighties) road racing locker and latterly the Kaiser Locker from Brazil use a sprag clutch type arrangement to fully lock under load, ie. they have a series of rollers running in a case that cam out and fully lock under power.
These aren't to be confused with a cam and pawl (ZF) type diff.
The big advantage of these diffs is that they unlock on a trailing throttle (unlike a Detroit Locker/No Spin) yet fully lock under power and so reduce corner entry understeer compared to a fully locked rear end, ie a spool or Detroit.
The downside with these (or at least the Weismann) was that you needed a specific additive chemistry for the lube otherwise the rollers would suffer what was known as 'popping', where the rollers would slip under load.
LSD fluids are a no-no, and apparently most syn fluids don't work.
Weismann now market their own syn fluid, naturally enough called 'Snake Oil'
(someone there has a sense of humour)
Nekarth, the manufacturer of the Kaiser Locker in Brazil claim you can use any gear/diff fluid with their Kaiser Locker, but I know that behind an auto tranny this thing is pretty seamless, put a manual in front of it and it clunks and bangs and can bite badly with on/off throttle applications.
I'm guessing it's suffering the same as the Weismann did back in the day, so what sort of characteristics does the brains trust reckon the fluid needs for proper operation ?
I'm guessing something like an aggressive MTF additive package, an increasing coefficient of friction as the relative speed between the rollers and case decreases ?
Just throwing it out there for an interesting discussion.
These aren't to be confused with a cam and pawl (ZF) type diff.
The big advantage of these diffs is that they unlock on a trailing throttle (unlike a Detroit Locker/No Spin) yet fully lock under power and so reduce corner entry understeer compared to a fully locked rear end, ie a spool or Detroit.
The downside with these (or at least the Weismann) was that you needed a specific additive chemistry for the lube otherwise the rollers would suffer what was known as 'popping', where the rollers would slip under load.
LSD fluids are a no-no, and apparently most syn fluids don't work.
Weismann now market their own syn fluid, naturally enough called 'Snake Oil'
Nekarth, the manufacturer of the Kaiser Locker in Brazil claim you can use any gear/diff fluid with their Kaiser Locker, but I know that behind an auto tranny this thing is pretty seamless, put a manual in front of it and it clunks and bangs and can bite badly with on/off throttle applications.
I'm guessing it's suffering the same as the Weismann did back in the day, so what sort of characteristics does the brains trust reckon the fluid needs for proper operation ?
I'm guessing something like an aggressive MTF additive package, an increasing coefficient of friction as the relative speed between the rollers and case decreases ?
Just throwing it out there for an interesting discussion.