VDC vs X-Mode

BriefObsessions

Forum Member
Joined
Jun 15, 2020
Messages
28
Location
Australia
Car Year
2016
Car Model
SJ Forester XT
Transmission
CVT
Sorry if this has been asked before, but how much better is X-Mode than VDC? From this demonstration here, it looks like VDC could handle most situations -

Can an older model with VDC be retrofitted (re-programmed?) with X-Mode? I highly doubt it but it doesn't hurt to ask the question ;)
 
Unfortunately I cannot help as my model's "VDC" means Very Dumb Car ;-)
 
Haha thanks Kevin. I'm sure that particular version of VDC does a good enough job :)

The reason I'm even asking this question, I'm trying to decide between buying an SH manual trans or an SJ CVT. I'd prefer a manual, but x-mode seems like it would get you more places.
 
Our (auto) SH has VDC. Can't say that I've ever noticed any difference from our (DR 5MT) SG, except that the SG handles better ...

The SH is SWMBO's, and has never been off the bitumen ...

Regardless of the scathing comments some make about the 1.19:1 low range, I have always found it very much fit for purpose.
 
Vdc is fine enough itself. It does the job. X mode is more software put in newer cars that control vdc. Sure you cant put that into older cars. Vdc has couple modes too, tc off/on .
New models must do better as they make that mode better so thats cant be same on older cars. But you can find solutions still . More momentum , diff line.
 
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BriefObsessions said:
From this demonstration here, it looks like VDC could handle most situations -
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VDC is good enough. According to one manual I read when X-Mode came out in the JDM market, VDC is just one function of X-Mode but it focuses on getting as much static friction to the ground as possible, hence the use of all the control units, except the BCU. More static friction, though, requires less wheel spin and it provided problems with some obstacles requiring more torque to the wheels. I assume that problem made Subaru program an extra mode for more wheel spin (Dual X-Mode). Still, those with just one mode, many are still able to get the wheels to spin more just by turning X-Mode off and relying only on the default VDC.

Those are from what I have read only and I had to use a translator for the brochure. My VDC experience is with my baby sister's BL5 turbo and it's VDC is for a completely different application.

BriefObsessions said:
Can an older model with VDC be retrofitted (re-programmed?) with X-Mode?
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It can be challenging as X-Mode is a function of the communication between many different control units. You still can have the VDC re-tuned using SSM3 at least. A good Subaru mechanic can adjust the delay for the traction control to engage. Older VDCs would engage the traction control to the free wheel after a few seconds but with SSM3, it's possible to shorten the traction control engagement time.

BriefObsessions said:
'd prefer a manual, but x-mode seems like it would get you more places.
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For me, driver input is more important. Manual and torque converter (TC) vehicles have different methods of clearing an obstacle but it really depends on the driver how he/she is going to maximise the gear he/she has.

The X-Mode, though, enables the driver to go really, really, really slow vs the regular auto.

I posted this before on another thread:

Throttle input is also limited so that the transmission gets just the right amount of torque needed and so that the TC doesn't spin too much causing unnecessary heat buildup, according to the brochure.
 
VDC is whole main system. X mode its just one option of that and it makes all more advanced its good. But doesnt mean pre x mode models couldnt do same things. Depends on engine too.
 
Hello from Arizona, USA-

Sorry this is reviving an old thread but the original question is basically the same as mine. I have a 2017 SJ Forester base model that doesn't have X-Mode. All the upgrade 2017s do. Since X-Mode is additional programming to (multiple?) control units, could my control units either be re-programmed or replaced with ones from an upgrade 2017 that has X-Mode?
The only hardware changes that are obvious are the X-mode switch and perhaps the multi-function display that shows X-mode is active.
Any guidance as to where to look, service manuals, factory docs, after market tuners, etc. would be appreciated.
 
yh would be nice if someone could actually reprogram those X mode modes or VDC itself do perform better , but i never heard yet of something like that exist.
 
@scot_c This question is always asked in camera forums. Except for highly specialized situations, the photographer is FAR more important than the camera ...

Same goes for cars - in almost every situation, the driver is far more important than the base car, assuming that approach, departure and ramp over angles are adequate.
 
Ratbag said:
@scot_c This question is always asked in camera forums. Except for highly specialized situations, the photographer is FAR more important than the camera ...

Same goes for cars - in almost every situation, the driver is far more important than the base car, assuming that approach, departure and ramp over angles are adequate.
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Agree, technique and judgement are the most important things. But there appear to be aspects of X-Mode that could be useful. As for the driver being the most important factor, a friend of mine ranged all over the Colorado mountains in all weather in a 2WD open rear differential Ford pickup truck. He had chains, tools, a portable electric winch and a pile of gear and knew how to use it all. Never got stuck, just slowed down for a while.
 
@scot_c , exactly my point.

I'm not against most technological improvements. It's just important to realise that skill and experience always remain important.

Some people could bog a 70 HP tractor (draw bar HP ... ) - I have when I was about 18 y.o. It taught me a valuable lesson!
 
This discussion has brought another question to mind - limited slip, specifically torsen/torque LSDs and VDC. I'm going to start a new thread.
 
Well vdc works ok with torque lockers so vdc will work with lsd too as some cars have it like mine allready
But good working vdc kinda no need in real lsd , locker that much better stuff. Vdc alone will stop wheels that are in air or spin in not too hard situation. Lsd wont do nothing there
 
scalman said:
Well vdc works ok with torque lockers so vdc will work with lsd too as some cars have it like mine allready
But good working vdc kinda no need in real lsd , locker that much better stuff. Vdc alone will stop wheels that are in air or spin in not too hard situation. Lsd wont do nothing there
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Thanks for replying again. I hope the situation that I encountered with VDC, 3 wheels with no power to them and one front wheel with least traction spinning doesn't happen often. My thought was that turning off Traction Control/VDC would restore power to rear wheels and an LSD would give me power to both rear wheels. I had a torque locker on another vehicle and didn't like the way it performed on slick road surfaces and applying power in tight turns.
 
@scot_c If I recall correctly the 2017 Owners Manual states to turn off VDC for that sort of situation and let traction control do its job.
 
I drove from situations when just 1 wheel had traction 3 not, but that on hard ground and not on hill . Then depends how you entered obstacle on low revs or high just preplan situation and maybe raise revs before hard stuff as vdc wont help later much if revs dropped too much . Mean if its finds it too hard it wont go like overload no it will better wont move but it will save your cv axles there .
 
Kevin said:
@scot_c If I recall correctly the 2017 Owners Manual states to turn off VDC for that sort of situation and let traction control do its job.
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As we say here in the states, and perhaps also in Australia, RTFM (Read The F***ing Manual.
Page 7-41: Vehicle Dynamics Control OFF switch...Use this switch in the following special situations....
* a standing start on a steeply sloping road with a snowy or gravel-covered surface
* extraction of the vehicle when its wheels are stuck in mud or deep snow.

In my previous non-Subaru vehicles without VDC, the button with that symbol (silhouette of a car with wavy lines below it) meant their version of Traction Control, i.e. the ABS acting as a pseudo limited slip differential. As I said in a previous post, that could cause the rear wheels to lock up if neither tire had traction. I have no idea why I didn't try pushing it off when I got stuck. But according to the manual, on my Subaru it turns off the VDC that is skid suppression but, as you said earlier, leaves traction control operational. And that may have been all I needed to get out.
Duh. Lesson learned.

Thanks.

Scot
 
scalman said:
I drove from situations when just 1 wheel had traction 3 not, but that on hard ground and not on hill . Then depends how you entered obstacle on low revs or high just preplan situation and maybe raise revs before hard stuff as vdc wont help later much if revs dropped too much . Mean if its finds it too hard it wont go like overload no it will better wont move but it will save your cv axles there .
Click to expand...
Thanks for the information. I definitely need advice on how the Subie works off-road compared to my former 4WD vehicles. It definitely sounds like the VDC was lowering engine power, and I was trying to start from a dead stop. Since I have the NA 2.5 liter engine, I hope it doesn't have enough power to snap a axle!
Knowing now that the button controls VDC (skid suppression) and not traction control helps me understand what happened and what to do in the future.
 
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