Torque Split & description of the MT/AT AWD system (Merged)

But that 55/45 feels very nice with VDC off on snow or mud car acts more like rwd lets you do donuts all the way or if going in streets and you push too much its tail happy. Very nice thing.
 
It has been a long time. But the info of interest related to how the majority of Subarus, which come with Active AWD, operate in practice might be buried somewhere here:

https://www.subaruoutback.org/forum...426-freessm-complete-access-your-ecm-tcu.html

Again, the nominal 60/40 split is just that, nominal. And the problem offroad is that there is no way to lock the center differential. You can argue that it all starts with the very limited wheel travel, but that's besides the point. Maybe someone can re-explain how exactly the clutch packs operate.
 
No need to lock it with VDC anyways. It does all good in right places on wheels that needs it.
On older 4eat you can lock center solenoid with switch thats what all says, so must be some truth. All non vdc cars can do it on 4eat. Some say 1st gears does same too it lock center. Its better so you no need wait for it to decide what to do saves time. Not sure what 1st gear does on vdc cars but it does something cars drives little different them on D. So maybe it bypass something too.
 
Yes, but the current discussion originates in another thread. The issue is that a 4EAT Foz had exactly the same problem with loose material over rock on an incline that I have had with the OB. In those cases, VDC is not enough. It fails to stop the spinning wheels and/or to move the car forward. The only remedy is momentum and that is a problem on account of control and risk of damage alike.

It does not matter if all 4 wheels are on the ground either. All three cases where I had that issue involved no lifted wheels. So, I speculated that the inability of most Subarus (Active AWD and VTD cars) to actually lock the center/keep a given split, is a key part of the problem. That, and maybe even more importantly the lack of low range gearing.

Subarus do poorly enough on clean rock; rock covered by sand/mud/volcanic ash/whatever is out of most Subarus' league; the capabilities of the highly modified Foresters of half a dozen ORS members are awesome to see but they do not change the overall picture.
 
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Basically, we have discovered that Subaru never thought we would take our cars where some of us do. All that info on torque distribution is at best limited to on road driving. If you own an SH or older Forester, and want optimum off road traction, you at least know now how to achieve it. For the SJ, I look forward to the day we have one with us to tackle that track.
 
Good comment Rally. What is the solution for the SH? SG can have locking centre but can that be used on the SH with VDC? Or perhaps you have some other suggestions?
 
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It’s been a while since I drove an SH, and I never drove it off road, so I am going off the comments of others. Please correct me where necessary. I understand the vdc can be turned off? If so, then if a manual then just do what I did to my SG. If an auto, do the lock on the “centre diff” and lock the rears.
 
You can turn off the traction control but the VDC remains active no matter what you do. I would like to know if the variable torque distribution centre diff is the same as on the SG. If so, it might be possible to lock it using the electrical switch as you have done and see if the VDC can manage it. I'd give it a go if I wasn't worried about it damaging something.
 
Is there a fuse which you can pull, or wire a switch in for the same effect?
 
Rally said:
Is there a fuse which you can pull, or wire a switch in for the same effect?
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The owners manual shows how to disable rear wheel drive by putting a spare fuse in a blank space in the fuse box but that's all I can find.
 
Yes. You can't make a manual front wheel drive.
 
Beachworm said:
You can turn off the traction control but the VDC remains active no matter what you do. I would like to know if the variable torque distribution centre diff is the same as on the SG. If so, it might be possible to lock it using the electrical switch as you have done and see if the VDC can manage it. I'd give it a go if I wasn't worried about it damaging something.
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older outbacks have proper VDC off button not TC button. and mine was pre button , so i didint even had button , but i made button from fuse , same effect. it turns all VDC systems off . later models have TC button only but thats even better. i would like to have TC switch as well.
manu just say that VDC not for offroad and other stuff, but they just didint tried that themselfs properly, because VDC helps me in situations like 1 or 2 wheels in air or they dont have traction , and then VDC stopps wheels that turns empty thou gives more torque to wheels that have some grip. tested it many times and it works like charm... yes works until some level, its not real low gear and not real lockers, but its works good if its not too much demanding. im mostly going off power first then i go off grip. not enough power and not enough low gear. so to have that TC button only and not VDc button would be great, because its just turns off that engine cutting thing and still leaves brakes on wheels thing. then some models can have MPT or VTD there. again different things. real VTD is better of course.
 
In other words, vdc is ok on road and in mild off road conditions.

When it comes to autos, I will leave it to others who know more about them.
 
well VDC subaru is better then earlier versions of active AWD for sure. because when you no need it you can turn it off and still have that 55/45 split without any systems. thats on older outbacks. foresters had straight VDC with TC switch .
because subarus are lighter they are actually very capable cars , they very popular in our country or other baltic countrys and russia. not much mods needed and they just go anywhere in our forests here. if you wont do anything with those famous large 4wd cars they wont be capable so much in stock mode too. some ppl here went to foresters from ZJ grand sherokees.
when i was on trip with local foresters club and they all where older models pre vdc ones . so all places that where harder they where needing momentum, where i was driving trough all that slowly without any worries or wheel slip. its just gives you that confidense to drive slowly not brake car not damage stuff with higher speed. i like it . because they all where on older active AWD system.
 
Rally said:
Basically, we have discovered that Subaru never thought we would take our cars where some of us do. .
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Extremely well said, but I think we always knew that:lol:
 
Found this today
worth a read, assuming it's genuine and you like formulas. :)
 
I didn’t read too far to realise my assessment above is half correct. Moreover, this vdc system is all about stability control and not at all about off roading. It would appear it will only appply brakes should the car get out of shape, be it understeer or oversteer. I didn’t read too heavily into it but it seems to be only on autos. From this it would seem that as long as you can do the centre diff lock, you could probably put a rear locker in without I’ll affect and dramatically improve off road performance. Of course, there’s only one way to be sure!
 
Ben Up North said:
Found this today
worth a read, assuming it's genuine and you like formulas. :)
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It was an interesting read but I struggled with the English expression at times and seeing it was published 18 years ago it might be a bit out of date.

Given the front/rear split figures, it sounds like a WRX auto. Its a pity they didn't use a Forester and give us some off road data. Good find nevertheless.
 
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