Quote:
Originally Posted by Nomake Wan
That makes no sense. "Open center diff?" In all the diagrams I've seen, it's clearly labeled as a limited-slip differential.
I'm lost, here. The VTD clutch does what, exactly? If it is fully disengaged, then what? It makes absolutely no sense, from an engineering standpoint, to have a setup so that failure of the VTD clutch to engage results in front or rear wheels rotating arbitrarily. A design in which the failure of the clutch (or disengagement of it on purpose) results in one or the other rotating every time, on the other hand, makes infinitely more sense. Such as Nissan's ATTESA-ETS.
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Nomake,
You are no doubt confused by Harvey’s statement,”The clutch plays no part in driving either end.” Think on what he is effectively saying. The centre differential has a fixed front rear ratio when the clutch is not engaged.
The complete picture:-
In respect of the JDM box with VTD clutch, a signal providing maximum energised time and current to the normally open solenoid “C”, will increase transfer control pressure by closing a bleed. This causes the LSD clutch to be engaged, resulting in front rear drive virtual lock up. This can proven by inserting the control fuse.
Failure of solenoid valve “C”, will result in the clutch not becoming engaged and therefore drive in accordance with the mechanical ratio, i.e. front 36.4%, rear 63.6%.
The US arrangement incorporates a normally closed solenoid “C”, so that a similar control signal, reduces control pressure by opening the solenoid and creating a bleed. Consequently the clutch is not operated and there is no rear wheel drive.
Failure of solenoid valve “C”, will result in the clutch operating and front rear binding.
These alternative arrangements in respect of solenoid valve configuration, prevents the need for mechanical alterations in respect of the hydraulics used in the two systems, as has been proposed by Harvey.
Cheers, Trevor.