J'sWorld

Nobody makes one there is no market not gonna happen.

h_____

Yep no standard fitment. The options seem to be what you've suggested....
1. buy a kit and take apart and work out how to fit
2. retro fit all the original gear from a car with front and rear factory diffs. Find out a way to manually activate it, as not easy to retro fit the electrics too.

I prefer option 2, although its clearly loads more expensive. Due to cost, this one is on the back burner....

If I had my time again, I'd buy a car with these options on, too far in and too expensive to swap now.

BigBearJoe

Okay, I guess I'm maybe just stupid but… Why do you really need a rear locker on these cars? Doesn't the traction control automatically send power to the wheels with traction?

993GT

I asked Quaife about this years ago, believe they said get 10 preorders and they'll make them...

garrett376

That's actually a great question. The "problem" with ABD (automatic brake differential) which uses braking intervention to stop a slipping wheel versus a locked differential, is that momentum is lost as well as more even drive force distribution to the ground. This increases the risk of getting stuck since enough force may not be able to be applied to the reduced number of wheels with traction to keep the vehicle moving.

BigBearJoe

Okay, I can see where that would make sense if you're running around in the dunes or snow or mud where you need some momentum. If you're doing low speed rock crawling would a locking rear differential be beneficial over traction control?

garrett376

Yes, on any loose surface there is a definite benefit to locking differentials, especially going slow over rocks - it's not just for maintaining momentum, but trying to gain it, too (moving from a stop). It comes down to that the vehicle needs to exert a certain force to move forward; if the ground cannot exert enough force against 1 tire, or 2, or 3 to get moving, then you're stuck. But if you have 3 tires to divide this force up with the ground below (in the case of center and rear differential locks + ABD), you have a far better chance you can actually move OR continue to move. If you have no locking at all and just ABD and all wheels are on a low traction surface (including rocks!), theoretically the PTM will try to help by routing power to potentially 1 wheel; but if the ground below is rocky and loose, or muddy and slippery, or sandy and slippery, it will not be able to exert enough force against the surface below just 1 tire to get moving. Now you're stuck! Locking differentials permits distribution of force to more tires (potentially 3 with the rear locking option, 2 without). That means less chance to get stuck. The locked differentials prevent or reduce the reaction of the ABD to traction loss, since the traction loss event may not occur at all with the locked differential.

There are also stability benefits when going down loose surfaces with a locked rear and center differential; similar to the effects of LSD's on race cars under braking.

nodoors

Except for ice... if you regularly drive on ice just remember that a locked, front diff can cause a loss of control when turning.