[Tuco]

I thought that the electronic meant that a computer monitored wheel speed and then determines clutch pack engagment with this information. But after reading more about these axles, as far as I can tell, the ELSD axles determine the amount of locking mechanically (hydraulic motor). The electric only refers to a solenoid that keeps fluid pressure from building in the system when the brakes are applied. Is this true or am I missing something?

Also, how much % wheel speed difference will cause the clutch pack to engage on these ELSD axles? For example if I drive around a corner, will the wheel speed difference cause clutch engagment? This happens on pure mechanical Dana 44 limeted slip differentials (like powerlock). We wonder how sensitive the newer hydraulic systems are.

 

[T-Rated]

Here's the most detailed description I've seen yet:
http://www.jeepforum.com/forum/member.php?u=106653

 

[TRZ]

Link didn't show any info related to this topic (for me anyway).

The locker is engaged after a wheel spins a quarter of a turn. It's pretty cool to see in action. You see the wheel without traction spin (about a quarter of a turn), the locker kicks in and the wheel with traction and the wheel without traction turn at the same rate.

 

[mendelmax]

If I got it right from all the descriptions over internet, it's pretty much like haldex clutch. It still uses the gerotor pump, like previous QD system. The main difference is that with QD II, the oil outlet has electronically controlled valve. When wheel slips, the gerotor pump build up the pressure, compressing the clutches. In the same moment, computer locks the oil outlet. It keeps the pressure until the system detects there is no longer any need for locking. Then it simply unlocks the outlet, allowing clutches to disengage.
Jeep engineers claim, the locking torque is more, than the system can deliver under normal operation. So I guess it is great feature- under some extreme load it will not hold, therefore preventing axle shaft breakage.
I guess we can't tell about certain amount of wheel speed difference, since it's electronically controlled. For example it monitors the steering wheel position. it knows when you are in turn, therefore changing slip tolerance. So it will be different in 4hi, 4lo, with wheel straight or turned, at high articulation etc.

 

[Tuco]

Okay, this makes more sense now. Thanks for that information. This system iis way more sophisticated then I was giving credit.

 

[07WKLtd]

I'm still dying to get a chance to do some wheelin' and see if QDII is as good as people say and can compensate for the IFS.

 

[mendelmax]

The main problem with QDII when wheeling is that the system is complex. It's one system and each parts cannot function separately. Therefore failure of any element will kill whole system. But that is a concern only with really, really hard wheeling, that most of us never do.
But to be honest, I liked more the idea of 1st QuadraDrive. I just like the simplicity, but it's only me

 

[TRZ]

The main problem with QDII when wheeling is that the system is complex. It's one system and each parts cannot function separately. Therefore failure of any element will kill whole system. But that is a concern only with really, really hard wheeling, that most of us never do.
But to be honest, I liked more the idea of 1st QuadraDrive. I just like the simplicity, but it's only me

So, you prefer a system that doesn't lock at all? :laugh:

I still remember the frustrated look on a friend's face as he tried to get his QDI-equipped WJ through the same obstacles I walked over in my ARBed ZJ. He was crossed up and his tires would just spin and spin.

 

[07WKLtd]

I got QDII because I was sick of the QT on my 98ZJ getting stuck if you buried the wheels on one side. I got stuck in a foot of snow on a flat driveway once. Weak.

 

[LEDFoot]

The main problem with QDII when wheeling is that the system is complex. It's one system and each parts cannot function separately. Therefore failure of any element will kill whole system. But that is a concern only with really, really hard wheeling, that most of us never do.
But to be honest, I liked more the idea of 1st QuadraDrive. I just like the simplicity, but it's only me

Except the nv247 used in QDI tends to die prematurely It's just not noticeable like the old nv249s.

 

[LEDFoot]

So, you prefer a system that doesn't lock at all? :laugh:

I still remember the frustrated look on a friend's face as he tried to get his QDI-equipped WJ through the same obstacles I walked over in my ARBed ZJ. He was crossed up and his tires would just spin and spin.

Sounds like your friend had a Quadra-Trac equipped WJ, not a Quadra-Drive.

 

[mendelmax]

We still don't know how 245 t-case and ELSD will perform in the long run in terms of reliability. So I wouldn't bash old QD.

Don't get me wrong- QDII is really impressive, but I think it would be better with regular, manually operated lockers and brake traction control. It would probably be cheaper also.

The last thing- QDII suits WK, because by design it's a bit less offroadable than WJ or ZJ. By saying this I don't mean "capable", since stock to stock WK outperforms them both in every term, at any surface (well, less clearance, that's the only problem). What I mean is that WK is too complicated for hardcore wheeling with water up to the roof etc.. So there another little piece of electronics don't make any difference But it would in ZJ or WJ. I really like the QD design.

 

[TRZ]

Sounds like your friend had a Quadra-Trac equipped WJ, not a Quadra-Drive.

Nope, he had a QuadraDrive.

I wheel with a couple WJers and they have removed their QuadraDrive axles and replaced with true lockers such as ARBs. We were all very impressed with QDII's positive locking performance on the same trails that their QDIs failed to lock up.

To be fair, these guys run 33s and 35s and QDI is known to have a problem with larger than stock tires. The WKs we've seen on the trail had 33s and locked up just fine.

 

[TRZ]

We still don't know how 245 t-case and ELSD will perform in the long run in terms of reliability. So I wouldn't bash old QD.

Don't get me wrong- QDII is really impressive, but I think it would be better with regular, manually operated lockers and brake traction control. It would probably be cheaper also.

The last thing- QDII suits WK, because by design it's a bit less offroadable than WJ or ZJ. By saying this I don't mean "capable", since stock to stock WK outperforms them both in every term, at any surface (well, less clearance, that's the only problem). What I mean is that WK is too complicated for hardcore wheeling with water up to the roof etc.. So there another little piece of electronics don't make any difference But it would in ZJ or WJ. I really like the QD design.

I'm far more concerned about the overall computerification of the WK than that the computer tells QDII when to lock up. If my lockers don't work out in the boonies, I'll take a tow strap to get out - frustrating but not that big of a deal. If the computer itself goes out, you're stuck.

Then again I suppose if the computer goes out on a WJ or a WK, you're also stuck.

 

[mendelmax]

TRZ, sure, but when you'll loose some sensor we don't know what QDII computer would do. For sure you would be left with no axle lockers, thats fine. But how about T-case and whole the rest? Does anyone have any info? Is WK still driveable without for example ABS sensors?

And about tires- that's true, first QD wasn't working well with anything above 31". Here I have great respect for QDII. Still think 100%, manually operated lockers would be better though.

 

[merlinTec]

Hi
Well it seems there a lot of you are interested in this so this is operation info to help you understand how it works.

OPERATION

The ELSD is similar to the Vari-Lok in that there must be a difference in the wheel speed to provide the fluid flow necessary to apply pressure to the clutch to lock the differential. However, the ELSD incorporates electronic control to decrease the time needed to lock the differential and increase the torque capacity.

The system uses a hydraulic pump, piston, and an electronically controlled solenoid to control pressure. The hydraulic pump uses the axle fluid as it’s hydraulic fluid.

The pump case is splined to the differential carrier and the pump rotor is splined to the axle shaft. The internal gerotor creates oil flow whenever the left and right wheels spin at different speeds. A pressure regulating valve (PRV) controls the oil flow. When a left or right wheels are detected to be spinning at different speeds (from the wheel speed sensors) the FDCM increases oil pressure to the clutch piston by activating the solenoid valve and restricting the oil flow. The piston compresses a wet clutch assembly providing additional torque to the lower speed wheel by locking the left and right wheels together.

When the antilock brake system or ESP is activated, the FDCM turns off the differential solenoid and the pressure bleeds off inside the clutch assembly unlocking the clutch.

The FDCM supplies power and ground to the front and rear axle valves.

Regards,
Merlin

 

[Tuco]

Thanks Merlin! Do you know if the locking is sensitive enough to lock while going around corners?

 

[CEPCNC]

I'm far more concerned about the overall computerification of the WK than that the computer tells QDII when to lock up. If my lockers don't work out in the boonies, I'll take a tow strap to get out - frustrating but not that big of a deal. If the computer itself goes out, you're stuck.

Then again I suppose if the computer goes out on a WJ or a WK, you're also stuck.

Computerification...that's a hell of a word. I'm gonna use that sometime in the next couple hours-lol

 

[merlinTec]

Thanks Merlin! Do you know if the locking is sensitive enough to lock while going around corners?

Hi
Trying to find some more info as to what speed it will cut out. I would guess it will cut off above 10 mph and then ESP takes over. You wouldn't want it cutting in around corners as this would be no good for stability or tire ware.
This is fun to play with we had one up on a ramp with the wheels free and if you turn one wheel the other wheel turns the other way, then if you turn it on both wheels go the same way.
Regards,
Merlin

 

[kreso]

QDI slower in reaction but capable. With 33" on wheels no problem.
QDII better and faster then QDI with same size 33".
NO problems whatsoever with both of them. Just regular service and checking the oil after deep water forging.
WK will run without ABS but braking is difficult.