Handbrake/rear diff cut off for rallying

[Myothercarisatractor]

Evening all

I am considering purchasing an older group a/b car to have a bit of fun in.

I like to think that I am reasonably well clued up with cars, however, I don’t know anything about rear diff cut outs for rally cars (I’m not even sure if that’s the correct name for them). Basically, many rally cars do not need the clutch to be depressed when pulling the handbrake, I imagine this is done by cutting the engines connection with the rear wheels. I can find very little information on it and no where to buy them online so I decided to turn to ph’s infinite knowledge! If someone could explain what system allows this to happen and where to buy it I would be very grateful!

Call me lazy all you want but my left leg hurts after a while haha!

Thanks

[GreenV8S]

I think you may be thinking of an active center diff.

[generationx]

Modern-era WRC cars often have a disengagement device on the front of the rear differential which is operated when the handbrake is used. Think of it as a form of hydraulic clutch.

Much less common on GrA cars, these were more likely (as mentioned above) to use the active centre diff' to disengage drive to the rear. Such things were not allowed in the first generation of WRC car.

In GrB I'm pretty sure such a thing was nonexistant, they were all fairly unsophisticated when it came to the driveline.