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  #21  
Old 5th December 2017, 05:25 PM
scalman scalman is online now
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cars101 gives this info about VDC outback models
Quote:
VDC All Wheel Drive VTD All Wheel Drive, VDC variable dynamic control model only
VDC: (variable dynamics control)
The overall name of the system, and of the model, of full time traction control that senses vehicle direction and uses brakes, throttle and engine management to control and maintain stabilty.
VTD (variable torque distribution) All Wheel Drive system that transfers powers front to back. Usually 45/55 front to back split.
The way the system operates
the VDC Outback is always in all wheel drive, using a Variable Torque Distribution (VTD) of 45/55 front-to-back power split. When there is slipping the VTD system will vary and adjust that front to back 45/55 power split.
When the wheels are spinning or the vehicle is not going in the direction it is being steered, the VDC (variable dynamic control) engine management system kicks in and will use brakes to slow down wheel spin and control vehicle direction, and also control engine output to cut back power to the wheel or wheels that do not have traction, again to reduce wheel spin and re-direct the vehicle in the direction it is being steered.
maybe foresters have diff specs, but outbacks if believe this info all VDC models using VTD.
but anyways my model is not listed anywere oficialy. 2.5 4eat with VDC is hard to find.
anyway using VDC as i call it helps me alot. in winter using VDC on snow its great, in mud turning VDC of and still have great split for better traction. on slow speed situations VDC helps to finds traction going slowly. active AWD needs momentum in most cases to go same places.
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  #22  
Old 6th December 2017, 12:38 PM
MiddleAgeSubie MiddleAgeSubie is offline
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VTD was exclusive to Tribecas and some H6 Outbacks (and on all H6 between 2010 and 2014).

It was temporarily available on FXT, I think 2007-8.

VDC has been on all Subarus since around 2009-2010.

There are no Subarus with VTD anymore. I think what the STi has might be similar but it is DCCD so not identical to the Tribeca and OB VTD.
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  #23  
Old 6th December 2017, 12:47 PM
scalman scalman is online now
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There are allways those rear models that shouldnt be too.
just very short video of me testing VDC off vs On on snow hill. everything same , just VDC off doesnt go nowhere forward. even with little momentum. where VDC on doesnt need momentum at all
https://www.youtube.com/watch?v=WG9au3wB0OU
and you can hear how its cuts some power when wheel its about to spin but gives its enough power just to move car forward. its like night and day differences in this particular situation.

Last edited by scalman; 6th December 2017 at 01:29 PM.
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  #24  
Old 7th December 2017, 02:33 AM
MiddleAgeSubie MiddleAgeSubie is offline
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Offroad ability=traction+clearance. The devil is in the detail, of course.

So...I will put it like this.

Traction A: keep the wheels moving:
1/4x4/efficient AWD (Subaru).
2/True locking center differential/effective enough CD (Subaru)
3/ABS-based traction aid (VDC. A-TRAC, BLD, whatever you wanna call it). Enough in most cases. Not enough in rock crawling. Remember, on a Subaru VDC is NEVER off. What is OFF is the function that cuts power to the engine.
4/True rear locker (used all over before VDC systems, used for rock crawling in vehicles with VDC).
5/True front locker. Extreme rock crawling. More uses on older vehicles with no VDC.

Vehicles with good low range and no true rear or front lockers like 100-series Land Cruiser (USDM) and 2007+ non-Rubicon Wranglers can still make it through very serious ledges thanks to A-Trac (Toyota term) or BLD (Jeep term for VDC). However, you still want those traditional lockers for extreme terrain or for frequent visits to difficult trails.

Traction B: controlled movement over harsh terrain:
1/ Auto with a powerful engine, at a minimum
2/ Low range
3/ Better low range, crawl ratio. Crawl ratio is a big topic for 4x4s.

Subaru offers nothing anymore. Toyota is generally about 2.7:1, as most Jeeps. The Rubicon, however, is 4:1. It can basically idle over crazy stuff.

Clearance. The thing about clearance is that it is not just about minimum clearance.

Clearance A: Minimum clearance
Minimum clearance is what rock you can straddle on otherwise flat terrain.
Solid axle 4x4: your differentials, usually a bit more clearance under front
IFS 4x4: usually the rear differential cover but on the GX 470 (US Prado derivative), it is actually at the front.
Subaru: pretty nicely tugged oil pan and nicely high rear diff, but highly exposed exhaust along length of car.

Clearance B: Relative clearance
This is the clearance that matters most. It is a matter of minimum clearance in relation to wheelbase. The longer the wheelbase, the more clearance is needed to go over stuff. I am not just talking brakeover angle, as in cresting over something. I am talking the ability to drive over undulating terrain, rocky or otherwise. Old Wranglers, and some more recent ones, the entry level trims, had modest ground clearance, but they could still drive over tough terrain because of the short wheelbase. Ditto Samurai. This is also what makes the old Foresters so successful off-road. They start with very modest minimum clearance and even with the typical 2" lift they cannot get really high. But the short wheelbase works wonders in harsh terrain. Actually, the 2009-13 Forester should also be as good since it starts higher and its AA/DA are better.

Clearance C: Rocker Panel height
This is one reason why Subarus are so hopeless in rock crawling. With a 2" lift and oversize tires, I get to a respectable 12" real life rocker clearance with aired down tires. But this is the bare minimum needed for many moderate 4x4 trails. This is less than half what modified Wranglers have. True, boulder-crawling is not the name of the game everywhere, but it often is in my corner of the woods.

Clearance D: Approach and departure angles
Subaru: 18-25 AA for stock
Gentrified 4x4: 23-28
Typical 4x4: 28-32
Wrangler: 40 and up.

Your Subaru winner here is the 2009-13 XT Forester. Generally, with a lift and better tires, all Foresters are going to be okay or even good. But the other Subaru models are a joke in this department. The absolute minimum needed AA, judging from my experience and from what Toyota did to its gentrified GX 460 in 2013, is 23 degrees. Everything less is simply forgettable. And 23 is barely enough on many moderate trails. There is a reason OB owners do what not to their bumpers.

DA is not quite as critical and a hitch can protect a vulnerable bumper (to a point).

Clearance E: Brakeover angle.
Most: 20sh these days, bare minimum
Good: 23sh
Best: 25-27. But you have to go to 80-series LC and 2dr Rubicons for these numbers.

I forgot what mine is now (22?). I lacked BA once, when I went up an optional rocky face, not noticing how sharp the top was. Oops. Not sure what I hit, it was a good hit but have not seen consequences.

Clearance F: Front bumper, AA, and front undercarriage
This is like relative ground clearance. Here is what I mean. The worst thing about an OB is the front bumper, right? But you can rephrase this as the best thing about an OB being the front bumper. Why? Because the front bumper is so awful that it acts as an early warning system. Chances you can go over a rock that later impales your oil pan are slim to none. But consider the USDM Nissan Xterra in its regular 4x4 trim (it has a better one). In this more common 4x4 trim, the X has a very vulnerable oil pan coupled with a good AA. So you can actually clear a rock with the bumper only to hit it with the oil pan, especially if descending a rocky hill. Ouch. This won't happen on a Subaru. Conversely, what drives me nuts about my front skid plate is that it has a low sitting edge right in front of the front wheels. So I was hitting that all the time before the lift. Had the edge been behind the edge of the tires, this would not have been an issue (may be impossible due to the exhaust tubes).

Clearance G: Footprint and Wheelbase
Wheelbase: see above, plus turning radius. But overall footprint, too, matters a great deal on tight trails. It also allows Samurais and old Foresters to go around stuff that others must negotiate. The disadvantage of small vehicles is on steep terrain with big ledges, but no street-drivable Subaru deals with big ledges.

Clearance H: Water fording ability
High-end off-roaders have 30" and up out of the factory.
There is a thread about Subarus here.

Beyond traction and clearance:

1. Reliability.
2. Weight.
3. Rollover angle. Hey, one thing I am not losing much sleep about!
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Last edited by MiddleAgeSubie; 7th December 2017 at 11:07 PM.
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  #25  
Old 7th December 2017, 02:39 AM
MiddleAgeSubie MiddleAgeSubie is offline
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Also, before someone brings the 1970s handbook on locking differentials, let me remind you of this:

The last time a Land Cruiser offered a mechanical rear locker in the US was 1999.
The last time any offroad trim 4x4 in the US did NOT offer VDC/A-trac, BLD was 2006.

These days, traditional lockers are only needed in serious rock crawling and there are only two SUVs on the US market offered for this: Wrangler Rubicon and Toyota 4Runner Offroad (a Prado derivative).
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  #26  
Old 7th December 2017, 04:46 AM
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That's some great information there MiddleAgeSubie, thanks!
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  #27  
Old 7th December 2017, 04:47 AM
scalman scalman is online now
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Vdc off is not 100% off on newer models.different story on older ones. I tested with it off on corner start sliding on snow, vdc did nothing at all, no abs, no power cuting.
Other models vdc i heard works differently just partly off or until certain speed. Mine is off all time.
Some people making abs off switches too .
Traction control and/ or torque control works really well on subarus. Newer x mode makes all even better.
Some people make long travel conversion to subarus. I think thats just makes most difference in offroad then. You get more flex means more traction.

I dont like oldschool lockers on 4x4 it just makes all simple. Traction control on new land cruisers / prado more interesting for me. Saw videos where newer model prado stock just mud tires went same tracks on deep mud as others oldschool heavy modified 4x4 with big lifts and lockers. So you no need any mods or lockers if you have good traction control.
Subaru could make it more advance too if they would wanted i guess. Like choose terrain or crawl control. Those are simple systems to control your traction from heavy to light. They just named fancy . subaru in general can go very far and being very simple cars and not heavy they can do it just fine. For me subaru was choice because no other AWD car cost that low and do as much as subaru does. Easy to fix, lots diy simple stuff, cheap parts

Time when i will think that my outback is not enough for me or i need to modify it heavily will be time to change car. Maybe go to grand cherokee.
Cant understand reason to put thousands in your subie just to make it more capable, make it to another car.
And everybody sees offroad for his likings for some its rock crawling for others overlanding is offroading too. Forest track is offroad and you not allways need more clearance . So depends where you live you choose car for your needs.
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  #28  
Old 7th December 2017, 05:32 AM
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Quote:
Originally Posted by scalman View Post
So depends where you live you choose car for your needs.
True. what I'd really like for the top of Australia is an Iveco Daily 4x4, matbe an Earthcruiser
http://earthcruiser.net.au/portfolio...-earthcruiser/
Bit out of my price range
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  #29  
Old 7th December 2017, 12:39 PM
MiddleAgeSubie MiddleAgeSubie is offline
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Quote:
Originally Posted by scalman View Post
Time when i will think that my outback is not enough for me or i need to modify it heavily will be time to change car. Maybe go to grand cherokee.
Cant understand reason to put thousands in your subie just to make it more capable, make it to another car.
And everybody sees offroad for his likings for some its rock crawling for others overlanding is offroading too. Forest track is offroad and you not allways need more clearance . So depends where you live you choose car for your needs.
Totally agree.

Except for the Grand Cherokee part. That will be a source of trouble. Not to mention the gas tank location. You really do not want to be hit from behind in those old GCs. The only Jeep I would get is the Wrangler, until 2006 and from 2012. The 2007-11s had awful engines and some other troubles.

Plus, it is all relative to the market where you are. Those old XT Foresters can be gems worth modifying more heavily, if you already have one. But buying an old Subaru turbo for off-road use is gambling.

EDIT: yeah, I would not be surprised if early VDC cars were not the same as later ones. Programming, too. VDC in the TB does not act quite the same as VDC in the OB offroad.
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Last edited by MiddleAgeSubie; 7th December 2017 at 02:17 PM.
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  #30  
Old 7th December 2017, 12:59 PM
MiddleAgeSubie MiddleAgeSubie is offline
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Quote:
Originally Posted by Ben Up North View Post
True. what I'd really like for the top of Australia is an Iveco Daily 4x4, matbe an Earthcruiser
http://earthcruiser.net.au/portfolio...-earthcruiser/
Bit out of my price range
Yeah, there was a thread about those at some point. Interesting stuff.

In the US, I will put it like this:

Best forest road/dirt road: Subaru
Best for the Southwest (rocks): Wrangler Rubicon
Best for the Southeast (mud): not my area, probably Wrangler, trucks
Best for open space off-roading: probably the Ford Raptor or another big offroad truck.
Best do-it-all: 100-series Land Cruiser or current 4Runner Offroad (a Prado derivative).

You can definitely overland in the US Southwest, but you do not have to. Even the most remote points can be accessed in a long daily trip or a very reasonable 1-2 nights trip, which is not really overlanding. The best setup for the US Southwest imo is an RV towing a 2-door Wrangler Rubicon.
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