Quadra Drive II in Current Jeeps

[modelbuilder]

Hello,

The current Commander and Grand Cherokee models have the 4x4 system called Quadra Drive II.

This system has front and rear ELSD's. The difference between a traditional ELSD and this system is the following....

http://www.4wdandsportutility.com/tech/0912_4wd_2009_jeep_grand_cherokee/index.html

The shift is smooth and quiet. The Electronic Limited Slip Differentials (ELSD) front and rear are NOT limited slip differentials, they're electronically actuated LOCKING differentials. They lock completely. The computer senses when rear, or front and rear, lockers are needed and actuates the differentials, keeping them locked for about 90 seconds after the event that prompted the actuation. The ELSDs are then unlocked until needed again.

Is this not the same thing has having a front and rear locker except the computer switches it on for you.


I guess this makes sense as other WK owners with QD II have told me the ELSDs are just as good as lockers.

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[R_Lefebvre]

Sounds good, but I would only want an manual over-ride so you can lock it in when you know you are about to get into trouble. It's better to lock before, than to start letting something slip and then lock it.

Much akin to quasi-AWD system. The majority of these systems these days don't have a differential in the middle. They simply have a clutch of some sort, and they are 2wd until something slips. That's usually too late, because once a wheel starts spinning, it's hard to make it stop.

 

[modelbuilder]

Except the current 2WD drive Commander and Grands...the AWD versions have full time 4 wheel drive. Always with 52% of the power going to the back and 48% going to the front.

I do see what you mean by wanting to manually locking the axles, but I'd like to see a test on how quickly it engages as slip occurs.


Looking forward to their follow up.




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[alexrex20]

i have an 07 GC Overland CRD with QDII and yes, it locks front/rear/center but never selectable (although by picking different modes you can encourage the computer to lock more quickly). it's pretty intuitive and like the "AWD" system on the JK Sahara, only needs a little bit of wheelspin for the computer to figure out what's going on.

 

[modelbuilder]

Would you say that it is comparable to having a selectable locker as far as traction on the trails?


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[Backwoods Rambler]

I would think that if they "locked", there wouldn't be a need for posts like this....Chrylser 8.25" selectable lockers?

So if they did in fact lock, it seems to me that the solution would be to swap in QDII axles for thier "locking" ELSD's.

There may be some credibility to this though. Here's what I found on www.wkjeeps.com

A key component in the Quadra-Drive II system is the ELSD – an industry first application – and the new benchmark for automatic traction differentials. The ELSD use electronically controlled clutch packs to automatically and instantly vary from slip to lock at each axle. This maximizes traction when needed without any of the on-road drawbacks normally associated with such a robust 4 x 4 system.

BUT; if it's up to the computer to determine the level of traction required, the system might never lock. Now If you could manually over ride that?.....VERY COOL :drool: :drool:

 

[modelbuilder]

They do in fact lock.

That thread, as you know, is a post about putting a locker in a WK with Quadra Trac II. Quadra Trac II does not have the locking ELSD.

Quadra Drive II has the locking ELSD...which were also featured in the current issue of JP magazine. They tested them out and said they were just just as good as having a selectable locker. The review also describes the ELSD as locking in milliseconds as opposed until waiting after full wheel slip to engage.(Just read it today).

With all the electronics that are involved it would cost too much to switch out an axle from a QTII vehicle to a QD Vehicle. You would need both new front and rear axles, new computer, a lot of wireing, plus other little bits of tech.

I made that post becuase no one makes a locker for my WK (With QTII) and it would cost too much to and would not involve a simple axle swap.





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[Backwoods Rambler]

All good to know, thanks for the nearly immdiate followup :ylsmoke:

That makes the GC appear to be a fantastic mild/med duty off road candidate. Not that we didn't already know that

 

[modelbuilder]

Ya. Its capable...although if I had done my research before buying it I would have gotten the HEMI with Quadra Drive II or a Toyota Landcruiser!

 

[Backwoods Rambler]

Really, the Hemi for an additional 25hp?

What did you get instead?

 

[Root Moose]

Wheel the wheels off it. Instead of focusing on the lockers get some lift and add a winch.

Be happy

 

[modelbuilder]

Really, the Hemi for an additional 25hp?

What did you get instead?

The First Gen (05-08) 4.7L V8 is 235 HP (What I have)

The First Gen (05-08) Hemi is 330 HP

Almost 100 HP difference. Plus the Quadra Drive II.




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[winkosmosis]

Instead of swapping all the wiring and electronics, why not swap the axle, and rig the locker for manual operation? That should be possible right?

 

[Root Moose]

Hard to say - if it is just triggered by a solenoid then maybe there is something like that possible.

If it requires some kind of a funky waveform then all bets are off.

Likely the former.

Need to see the FSM. Any torrent files for these trucks out there yet?

 

[modelbuilder]

Instead of swapping all the wiring and electronics, why not swap the axle, and rig the locker for manual operation? That should be possible right?

It would interfere with the vehicles TCS. Its complicated but needless to say it has not been done in a WK or XK yet and there is a reason for that.



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