Differential question.

[DANACO]

My best guess is durability. Everything I've ever read about differentials says that open diffs are the most reliable, longest lasting out of all the different technologies out there. Being that it's RWD very close to 100% of the time for most people, it would make sense to have the most reliable option back there.

Torsen's are very reliable and strong as I know them, had one in the rear of a pickup with over 100k. You can leave the Raptor in 4W Hi all the time if you wanted, they don't say you can't or shouldn't, so I say the reliability thinking is not it.

 

[jabroni619]

Torsen's are very reliable and strong as I know them, had one in the rear of a pickup with over 100k. You can leave the Raptor in 4W Hi all the time if you wanted, they don't say you can't or shouldn't, so I say the reliability thinking is not it.

The reason you shouldn't use 4wd "full time" has nothing to do with the operation of front or rear differentials. It has to do with the operation of the transfer case. You may be right in that reliability isn't the reason why there isn't a Torsen in the rear, but being or not being able to use 4wd full time is a completely separate issue.

Also, being able to go 100k without a diff issue isn't a bragging matter. I'd be shocked if any type of diff didn't last well beyond 100k.

 

[HankTheTank]

what would be the reasons they don't put a Torsen in the rear end ? Seems like it would do everything all the other controls do without the complication.

Because a Torsen is a limited slip slip. For what the Raptor was meant to do, a fully locking rear diff is more appropriate. You see rear Torsens in track cars. Not in off road vehicles.

I'm curious because there's an off-road trail nearby with a pretty steep hill that my friends and I have been trying to summit, none of the vehicles we've used have a locking diff so I wanted to attempt it unlocked for a more "apples to apples" comparison. I don't have my Raptor yet but the adventure planning is well underway.

Put the Raptor's terrain mode to "Mud/Sand". This will disable many of the electrical nannies (I think AdvancTrac is included) and also put you in 4wd with the diff locked. But you can manually unlock the diff to do your apples comparison.

 

[jabroni619]

Because a Torsen is a limited slip slip. For what the Raptor was meant to do, a fully locking rear diff is more appropriate. You see rear Torsens in track cars. Not in off road vehicles.


Put the Raptor's terrain mode to "Mud/Sand". This will disable many of the electrical nannies (I think AdvancTrac is included) and also put you in 4wd with the diff locked. But you can manually unlock the diff to do your apples comparison.

So I suppose the next question is... Is there a such thing as an electronically locking Torsen differential?

 

[Frank N]

I don't see a need for a Torsen, if you can lock it.

If you can't lock it, like the front end, torsen is great option.

 

[rtmozingo]

Has anyone done more experimenting with this?

Running in Baja 2H won't let you lock the rear, but from my experience with the setup, the rear seems to act like a LSD (meaning, brakes are transferring power).

 

[xxaarraa]

So I suppose the next question is... Is there a such thing as an electronically locking Torsen differential?

ehhhh. So much misinformation in this thread. At least you are trying to learn so I will be constructive.

TorSen (short for Torque Sensing) is an LSD. It will allow one wheel to spin UP TO a certain amount more than the other wheel before it locks them both. The threshold is called a TBR or Torque Bias Ratio. In the Gen 2 Raptor, TBR is 3. So, the torsen is an open diff till one wheel spins 3 times as much as the other, then it locks and they both spin at the same rate.

Anytime you lock a diff either electronically or using air compressors (ARB), you have what's called a selectable locker. When you select the lock, you take away any torque bias between the two wheels and both wheels spin at the same rate. You lose the advantages of letting one wheel spin slightly faster than the other and in return, you gain a true 50-50 split in power, on command.

LSDs are good for performance cars and higher speed driving in general because you want a bit of slip and not be fully locked all the time, however you dont want a complete open diff either.

Locked diffs are generally good for slow speed crawling. And deep snow.

There is no such thing as "electronically locking Torsen"

 

[ViMo]

All Gen2 Raptors have Torsen differentials ? ... Or it is an option ?

 

[Frank N]

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All Gen2 Raptors have Torsen differentials ? ... Or it is an option ?

0ption on 800 and 801

 

[Muchmore]

It will allow one wheel to spin UP TO a certain amount more than the other wheel before it locks them both. The threshold is called a TBR or Torque Bias Ratio. In the Gen 2 Raptor, TBR is 3. So, the torsen is an open diff till one wheel spins 3 times as much as the other, then it locks and they both spin at the same rate.

I think you mean they are allowed to spin at up to a 3:1 ratio and no faster. They never "lock" but can never spin more than 3 times faster than the other.