LSD vs Lockers in Syncro

[Fritzer108]

Hello!

I acquired 1987 Syncro Doka resto project a few months ago which has been sitting dormant for the time being. I just landed a new job and will soon have to funds to invest in the driveline. I plan to use this van mostly for hunting and other off road adventures. This brings me to my current question: would torque biasing diffs or lockers be more useful?

My first option would be to have GT torque biasing diffs installed front and rear in the existing AWD driveline of the Doka.

My second option would to purchase a syncro driveline with front and rear lockers (currently available to me).

Which combo would provide the best bang for my buck? Both options will be pricey, but I am ready to invest in the driveline. Most of my driving would take place is mud, snow, and ice, so I'd like to build a driveline to handle this.

Any necessary changes required to accomodate lockers in the Doka is not an issue, but I'd like to hear what others have to say about these two options. TIA![/img]

[MarkWard]

The syncro conversion I did a few years ago went this route. Front differential got a Peloquin differential, but with a locker too. Thought process was, unless you are on real slip surface, you need the differential to “slip” to turn. Once locked the van really wants to go straight. I felt that was important. I read though that Peloquin has slowed production. You might need to see.

For the rear, I stuck with the stock locker. Partially from keeping expense down. Thinking was when needed I could lock the rear as VW intended. I did not go the route of the decoupler. I stayed stock and resealed the VC.

But, I ended up selling the syncro. After building one from scratch, I realized how many extra points of failure they have. Our 2wd suits our use and I did add a Peloquin to it.

GT was working on a limited slip and I believe was souping up ZF limited slips. Some of your choices maybe dictated by what’s available. Also your intended use.

[Sodo]

I have front & rear Peloquins.
I NEVER feel any "locking" input from the front Peloquin on the steering wheel.
If it is limiting the slip, it's very very subtle.

I describe the action of the Peloquin as "much more limited than an open diff".
You can watch these videos to get your own ideas of how a Peloquin compares to an open diff.
There is really "no comparison" to a full-locker. What the Peloquin does, is very subtle in comparison to a locker.

In the distant past (2015) my gearbox oil was FULL of metal, and back then, I was really impressed by how hard the Peloquin locked up.
Going in a circle on gravel, if I just touched the throttle off "coast", it would start to lock.
It would lock up on pavement on a tight turn if there was any sand or dirt on the road.
These days, with GL5 gear oil that's filtered and clean as honey, it doesn't behave like that.

I don't think they "bias" much.



Link
This video (^^ABOVE^^)shows a real good comparison to an open diff, you can see it limiting slip .

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Link


There's another Syncro option you can consider which is the "Solid Shaft", replacing the Viscous Coupler with a steel spline. In that case you MUST install a decoupler too.

You lose your “Syncro AWD” on snow, gravel, wet road etc, but gain significant off-road ability, because there's "no delay" in power to the front wheels.
For example you can get up ontop of sand.
Whereas the Viscous coupler lets the rear wheels start to dig in before the fronts start to pull. And you never get up ontop of the sand.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[flomulgator]

Your question is kind of a 2-parter. Best bang for the buck? Stock system with chains on all 4 tires.

But dropping the money part changes the question to simply "what best fits my use case?" Which could perhaps use a bit more description of conditions, because it's very specific. If you are more concerned about icy highways and unplowed forest service roads, a front-center-rear AWD setup with peloquins or LSDs front and back is going to work far better and deliver more control. If you are getting rowdy in deep snow, mud puddles, and slippery grades deeper in the backcountry, all lockers is the way to go.

One thing to keep in mind if you can't decide which side of the fence you're on, these vehicles don't have much suspension travel and are more likely to lift a wheel in an off-camber situation, and when that happens a TBD like a peloquin will not function. An LSD will.
_________________
She's built like a steakhouse, but she handles like a bistro!

[Wildthings]

Years ago I had a friend with a Jeepster that had limited slip front and rear. In one instance he couldn't angle up a sidehill covered with wet grass as his rig continually turned down hill on its own. No one with open differentials had a problem with the hill even one guy with a Dodge Dart, which caused the owner of the Jeepster to take a pretty good ribbing.

For whatever reason my Syncro came to me with a front differential lock but no rear lock and believe me you don't want to have it locked unless you 100% need it as the steering is really dicey on snow or ice when it is locked.

[syncrodoka]

Rear locker will get you out of more problems than a front locker. Once a tire goes up in the air(it will) the locker will keep you moving forward. Regular awd will get you through a lot of stuff as long as the VC is working

[SCM]

[DanHoug]

[Howesight]

Our rig came with the locking rear diff. We added a VW front diff lock and a de-coupler. For getting out of trouble, whether that is deep snow, slush, or more commonly, mud or uneven ground that will put a wheel in the air, nothing is better than locking front and rear diffs.

The Peloquin torque-biasing types of differentials are great on the road, but not so much off-road. They depend on both wheels of the axle in question being on the ground. If one wheel is off the ground, the locking and/or torque biasing action cannot occur.

I thought about using a solid-shaft in place of the viscous coupling, but Darryl Christiansen (RIP) of AA Transaxle, talked me out of that. (he was correct to do so.) He said that the solid shaft approach would limit any use I might want to make of AWD when on the road. Let's face it - - the Syncro VC approach allows you safely to use AWD on roads where the traction can continuously change, as happens in so much winter driving. The other thing he noted, in answer to my quesion on the point, was how very quickly the VW factory VC reacts to loss of traction on one wheel. I had thought that a fair bit of wheelspin would occur before the VC locked up. Not so, he pointed out. So, when crawling in mud or gravel, for example, the VC locks up as soon as the low-traction wheel turns even a quarter revolution- - usually less.

As time marches on, I think, the older your VC is, the stiffer it gets and its engagement is sufficient for even the worst off-road conditions. I don't like chewing up my tires in the 7-11 parking lot, so on dry pavement, I leave the de-coupler de-coupled. In the rain and in the snow, I couple up.

Having used my locking front diff, even on very loose gravel or mud, it is apparent just how much it affects steering and pushes the vehicle straight ahead. To me, having the ability to lock and unlock both diffs on demand is very important.

I am not opposed to torque-biasing diffs in any general sense. We have a brace of Audi Quattro cars that feature front-to-rear Torsen diffs and locking rear diffs or torsen rear diffs (like the Peloquin). These work well, but these cars never see off-road conditions or a wheel in the air (not yet, at least. )

For a vehicle used in the conditions you would expect when hunting, selectable locking diffs are the way to go. One added comment - - for those in the rust belt, it's important to maintain the locker actuators since the operating shafts are susceptible to corrosion.
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'86 Syncro Westy SVX

[Sodo]

[zerotofifty]

For me I have a locker in the front axle, and a trutrac LSD in the rear for my Jeep. That way I have the use of the LSD for 2wd performance at all times, on pavement, and when in 4wd I have the option of turning on the front locker. Many offroaders like this set up, locker in front, and LSD in rear.

What is an LSD?
Working in Semiconductor we had a defect issue, under the microscope we sometimes saw photoresist residue, the defects were long skinny bits of the polymer photoresist that regular O2 plasma and solvent did not remove. We called them Long Skinny Defects, LSD.

For all you acid tripping types, LSD has another meaning
_________________
Sorry About That Chief.

Give Peace a Chance.

Words to live by.

[Sodo]

[4Gears4Tires]

I think an LSD in front and a Locker in the rear is the best all around set up. Or the opposite. But with an LSD in one end, it'll always be engaged for better traction and the locker will be available to pull yourself out of being stuck.
_________________
'87 Syncro Ferric Oxyhydroxide Superleggera Edition
'85 Westy Sciuridae Domus Edition

[Sodo]

I think once you have a locker in the rear you are at 80%.
Solid shaft moves you to 90% (but loss of AWD).

Peloquin(s) add a few single-digit percents along the way.
Its subtle in comparison to a locker.

Reasonable that the solid shaft coupler could be more effective mod than a front locker, and certainly in sand.
But with the solid shaft you lose your AWD for snow, gravel, wet roads, and novice drivers benefitting from the legendary Syncro AWD.

A driver who understands the drivetrain can still use solid-shaft-4wd judiciously in those conditions
but you can't just let your kids or novice drivers use 4wd willy-nilly anymore.

With a solid-shaft, it’s no longer “Syncro AWD”, it’s now a 4WD,
and a somewhat fragile 4WD in comparison to a Ford or Jeep.
_________________


'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[ottoman308]

I was gifted a 6spd STI transmission, and was debating losing the locker for better driveablity, and at least having limited slip. I already run a decoupler, and thought of possibly adding a front locker for emergency purposes only.

[Sodo]