Switchable centre diff lock?

Bumpty · Post by **Bumpty** » Thu Feb 21, 2008 3:25 pm

I'm very curious to how this can be done to cars?
Our tractor has it, and what a difference that little button can do... But thats a tractor...

Why isn't it very common to have this done to cars, I've heard some of the new 4WDs are becoming more common for having it, so is it just money being the issue...

Please discuss

By the way, Subafury prompted this thread

Quote ripped from another thread.

Subafury wrote: with a switchable centre diff lock

BrennyV · Post by **BrennyV** » Thu Feb 21, 2008 5:07 pm

I have this box in my Leone. It’s a EA82ftawd 5MT from a jap spec Leone RX. It has a vacuum operated centre diff lock, with lo range gearing. I’m assuming that it was never released in oz delivered versions as the need would have been minimal for Australian road conditions. I also know they were comman in the USDM models also.

discopotato03 · Post by **discopotato03** » Thu Feb 21, 2008 6:24 pm

If you had all the different bits you could convert a PT 5 spd box but its probably easier to get an original one or an AWD Vortex box which is the same but single range .

Mine is a converted (DR) Vortex box and the back up is a std AWD Vortex box .

Horses for courses , for AWD tarmack the Liberty box is probably better where for off road the AWD L box better . The reason I say this is because any open centre AWD box can lose all drive through one spinning wheel . The centre diff will proportion all torque out the path of least resistance which means towards whichever diff has the spinning wheel and from there to which ever side drive shafts wheel has no grip .

In a certain organisation we have issues with permanent 4WD and 6WD trucks which also do this . They have diff locks but thats not the best way to drive them on a hard surface . Sometime difficult to get the locks to let go . The Lib/Imp system has a viscous clutch to limit the difference in speed of either side of the open center diff . So unlike the L type AWD box it wont send all the drive out one side .

The best system would have been the viscous hub and a diff lock .

A .

mattl200 · Post by **mattl200** » Thu Feb 21, 2008 10:14 pm

i built one of these boxes for my off road brumby
adding the lseries low range and using front liberty cases to bolt straight to the ej22

and will (my sti) has done the same for his wagon

Thalass · Post by **Thalass** » Fri Feb 22, 2008 9:40 pm

Man... Switchable locking diffs would be great. Though it ads complexity - and despite being a rabid geek, when it comes to cars I think they should be as simple (and therefore reliable) as possible. Also having a switch for that sort of thing is cheating! Like on that damn mitsubishi outlander.

Rob_D · Post by **Rob_D** » Fri Feb 22, 2008 10:03 pm

Thalass wrote:Man... Switchable locking diffs would be great. Though it ads complexity - and despite being a rabid geek, when it comes to cars I think they should be as simple (and therefore reliable) as possible. Also having a switch for that sort of thing is cheating! Like on that damn mitsubishi outlander.

I considered an Outlander before I bought my Outback, As I remember it even though the switch is marked "4 Wheel Drive Lock" it doesn't really do that. From what I remember on the Outlander forums it still allowed the power distribution from front to back to vary.

Edit: Here it is:

"For driving in particularly challenging conditions, such as snow, the driver can select "4WD Lock" mode. In Lock mode, the system still apportions front and rear torque automatically, but enables greater power transfer to the rear wheels. For example, when accelerating on an upgrade, the coupling will transfer more torque to the rear wheels immediately, helping to ensure that all four wheels get traction. In contrast, an automatic on-demand part-time system would allow front wheel slippage before transferring power, which could hamper acceleration.

In dry conditions, 4WD Lock mode places priority on performance. More torque is directed to the rear wheels than in 4WD Auto mode to provide greater power off the line, better control when accelerating on snowy or loose surfaces, and enhanced stability at high speeds. Rear wheel torque transfer is increased by 50 percent over the amounts in 4WD Auto mode - meaning up to 60 percent of available torque is sent to the rear wheels under full-throttle acceleration on dry pavement. When in 4WD Lock mode, torque at the rear wheels is reduced by a smaller degree through corners than with 4WD Auto mode."

Reading about the Subaru VDC I think it is probably better than the Outlander system.

Rob