Subaru AWD binding question.

[0cean]

So, there is all the talk about awd and problems binding on the other thread. (I’m posting here as not to derail the lively discussion.) my question is, would a Subaru transmission with an LSD and a Syncro front diff with a solid shaft and LSD, have binding issues on pavement?
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[Waldi]

Yes it would.
A LSD without elec or manual locking has a preselected (by pressure) slip, like the 40% LSD in 2wd boxes.
You can feel the rear tires rubbing with the rear LSD in close truns.
It would be worse in close turns and it would not transfer automaticaly up to 100% torque to the front wheels if needed.
Than a LSD works with friction and a VC with "sharp force" on the silicon oil.
A LSD overuses faster.
The VC system is the best non electronical system.

[Jon_slider]

[Waldi]

If a system do not "bind" in turns it will also not bind if 1 axle loose traction.
Useless offroad.

Same as on a 2wd diff with lsd, there is binding between left and right wheel.
If there is no binding, there is no traction on both wheels.

The VC has a small binding in turns, which is increasing automaticaly to full binding if needed.
A lsd works not automatical. Its preadjusted to a fix number.

And no, a system that turns the wheels with less weight more (first) than the wheels with more weight, is not better.

[D Clymer]

All of the Subaru 5MT and split-case 6MT center differentials are standard mechanical differentials with a small viscous coupling integrated that acts as a limited slip medium if the velocity of one axle significantly speeds up relative to the other one. There is a certain amount of allowance built into this viscous lock that allows the vehicle to be steered on pavement without it locking the diff. Regular 5 speed AWD Subaru cars turn nicely on pavement without binding. An adapted Vanagon should behave the same way.

[Waldi]

If it is a VC in the Subarru diff and not a lsd, it will "bind" also an amount of torque from the beginning. Depends on the medium inside, which should also be silicon.
You just dont feel it, because it is set very soft, and will be not as effective offroad like the Syncro one.

The Subarru is not known as a offroad verhicle but more a street one.

Here there are the different Subarru Systems.
Funny is to see, that the newest System is set to 36/64 front/rear, and can be set electonicaly up to 50/50.
The engine will never transfer more than 50% torque to the front wheels.

http://www.awdwiki.com/de/subaru/

[D Clymer]

The Subaru AWD system with 36/64 dynamic split is not the one used in these 5 speed and 6 speed cable shift transmissions. The one used in these basic manual transmission cars is "Continuous AWD." It's the original Subaru full-time AWD system that dates back to 1987. It's a completely mechanical system with a 50/50 dynamic torque split through a viscous limited slip mechanical differential. If you drive a Subaru Forester, Legacy, or Impreza with this system, it doesn't bind to any perceptible degree.

[Waldi]

I know that it is not the new Impreza system.
Have read my own link

But, it use a VC it will bind/transfer torque.
A VC as you can see on the graphs, always transfers an amount of torque.

This remembers me to the discussion, that the Syncro VC do not transfer torque to the front on pavement straight on.

If you fill the Syncro VC with silocon with low viscosity like 10.000, you wont feel any binding in turns, but the wheels will need more slip to angage AWD to 50/50.

Do you have a sheme of power flow from this model ?

[0cean]

[IdahoDoug]

I suspect the rear wheel binding on a FWD car with a VC would be less dramatic than the Vanagon's layout. And a sharp turn such as parking means the front driven wheels are spinning faster than the rears in this situation, creating some lighter dragging of the rear tires if anything.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Waldi]

What you call dramatic, others call a future.

I would not change to a Subarry system even if i got payed for it.

[IdahoDoug]

I've personally owned 4 Subarus, a Vanagon Syncro, 2 Quattros, 3 full time LandCruisers, A full size full time Montero, and driven countless others. The Subaru system is a great setup that has changed with the times to get even better. I would have no problem switching to a Subaru system and I don't understand the hate.

Doug
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[D Clymer]

[flomulgator]

The VW viscous coupling is the single greatest achievement in the history of four-wheel driven systems. Attempting to put in anything else under a Vanagon will cause the wheels to lock up as soon as the vehicle is turned. If you survive the 4 wheel skid off the road, the shrapnel that is produced by the seized and loaded driveline explosion will finish you off.

You have been warned. Stay true to OEM VW!
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[0cean]

[human compass]

I'm just getting ready to send my van off for a 2wd to subaru awd conversion. the suby tran will have a lsd. the syncor front diff will not. I'll definitely report back to the group (if I don't explode in a fiery mess )
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84 Westy Syncro- 3.3L SVX stage 2 tune,subaru gears 6speed with tbd, front locker, porche brakes x4, aux tank, radflo susp

[FrankenSubySyncro]

I am putting a Subaru 5spd awd in my svx vanagon with front locker. I have a friend who has gone through 3 syncro transaxles with an svx and he is reputable rebuilder. I have a fully locked syncro also so it is not one or the other for me. There are valid situations to do the Subaru awd trans. It comes down to owner preference. My daily driver is a Subaru forester with rear lsd and I like the awd system. The subaru transmission is much easier to work on and I have rebuilt a syncro transaxle.

I wouldn't recommend a lsd in the front. I am using a torsion diff in the rear with my Subaru transmission
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Syncronize it!
1987 Franken Syncro (converted 2WD auto)
2004 2.5 SOHC Subaru
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[human compass]

check out my syncaru 16 awd thread. halfway through the conversion.
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84 Westy Syncro- 3.3L SVX stage 2 tune,subaru gears 6speed with tbd, front locker, porche brakes x4, aux tank, radflo susp

[FrankenSubySyncro]

[human compass]

super cool. are you going to post some build pics? Ild love to see them!
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84 Westy Syncro- 3.3L SVX stage 2 tune,subaru gears 6speed with tbd, front locker, porche brakes x4, aux tank, radflo susp