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VDC, DCCD, and SI-DRIVE Explained! (Great Info)

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#64 ·
NigelJoseph said:
Weird, I thought the torque split never changed. I thought DCCD just varied the amount of lock used on the differentials.
Click to expand...
It has nothing to do with the front or rear differentials which is what I think you mean. Changing the amount of lock up on the center, changes the torque split between front and back.


This was referenced in the first post and will explain all this in pretty good detail: Subaru Drive Performance Magazine : DCCD - Driver Controlled Center Differential
However, I believe the torque split numbers are wrong. Sometime before the 08 year, it was changed to a 41% front/59% rear split (I believe that is the correct % split).
 
#66 ·
when tracking, i usually have S# and VDC OFF (as one of the posters mentioned, having VDC ON is quite intrusive)...

and depending whether its a big/fast circuit, or a mid-sized circuit - i either switch between half-lock or free, respectively...
 
#70 ·
Hi guys,
Below are the instructions copied from the owner's manual of my 2010 STI Special Edition. My car functions this way (hold the button down more than 2 seconds for the yellow light).

Traction mode
This mode restricts the functions of the Traction Control System and Vehicle Dynamics Control System and thus delays utilizing their functions as a reaction to vehicle behavior in comparison with the Vehicle Dynamics Control mode. This mode should be used in driving situations where the vehicle dynamic performance will improve without decreasing engine torque control.
When the switch is pressed briefly during engine operation the Traction Control OFF indicator light on the combination meter illuminates in green. . . . . .

Vehicle Dynamics Control OFF mode
This mode allows only the ABS control. This mode should be used in an emergency situation such as getting out of snow or mud.
When the switch is pressed for more than 2 seconds during engine operation, the Vehicle Dynamics Control OFF indicator light on the combination meter illuminates in yellow.

Below is an excerpt from the Drive Performance Magazine about the 2008 STI (also post #1):
VDC – the default setting, optimized for daily driving situations. There are no warning lights associated with this mode, which enables all controls for ABS, the Traction Control System (TCS), and VDC.
Traction – set by holding in the VDC off switch, which turns the VDC warning light green. This setting is more performance-oriented, with less-aggressive stability control. Engine torque-reduction control is disengaged.
Off – set by pushing the off switch once. This setting turns off stability control and the traction control functions for emergency situations, such as getting out of mud or snow. It leaves ABS and incline start assist active.

My car is new and I haven't yet figured out what does what. Can someone please definitively state that either the cars have changed, the article is wrong, and/or that my version has always been correct?

TRACTION: You push the button once for limited traction control and limited VDC. The light turns green.
OFF: You hold the button down to turn both off. The light turns yellow.

Thanks for your help,
Don
 
#71 ·
^^^)08 vs 09,10 STi vdc button operation is flip flopped. 08 if you push once it gets you off mode. 09,10 if you push once it gives you green mode. The colors mean the same mode no matter what year you have. :tup:
 
#73 ·
Lets say you are in a snow filled parking lot, getting out of your space and then driving in the parking lot. Would you put it in LOCK and then switch out just before getting onto the paved road?

Or is LOCK only for getting out of the parking space and then it should be turned down since you will be turning your wheels?
 
#74 ·
DCCD is da shiznit but VDC & SI-Drive are both crap (STi's need FULL power ALL the time by just regulating your foot, not by turning stupid dials & pressing buttons-leave that **** for the Forester & Legacy man)! Rally cars have no use for such power-robbing rubbish!
 
#75 ·
D0WNxSH1FT said:
Lets say you are in a snow filled parking lot, getting out of your space and then driving in the parking lot. Would you put it in LOCK and then switch out just before getting onto the paved road?

Or is LOCK only for getting out of the parking space and then it should be turned down since you will be turning your wheels?
Click to expand...
Lock should be used when you're driving on a surface that is low friction and you are not going to be making very tight turns. You shouldn't need lock to get out of a parking lot, the differential should take care of you in any mode.
 
#76 ·
hillhucker said:
Lock should be used when you're driving on a surface that is low friction and you are not going to be making very tight turns. You shouldn't need lock to get out of a parking lot, the differential should take care of you in any mode.
Click to expand...
So when does anyone use Lock? Auto + seems to take care of most every snowy situation besides maybe being stuck in some really really deep snow?
 
#77 ·
I am not positive, but i would say lock would be good on real loose or muddy dirt roads. Sorta like when in an off-road vehicle you lock your center and hubs. With auto, if the road conditions get too loose, it might put too much stress on the system. I'm just hypothesizing.
 
#78 ·
hillhucker said:
With auto, if the road conditions get too loose, it might put too much stress on the system.
Click to expand...
It would be more since lock is maximum force, lol. Auto would at least give the system time to unstress when not sliding around a corner.

There really isn't much difference in stress as long as you're not on tarmac. It all comes down to how it handles. I've experimented with it, and I see not much use for it outside of slow tight corner handling on loose surface. Like ice.
 
#79 ·
Sabrewings said:
It would be more since lock is maximum force, lol. Auto would at least give the system time to unstress when not sliding around a corner.

There really isn't much difference in stress as long as you're not on tarmac. It all comes down to how it handles. I've experimented with it, and I see not much use for it outside of slow tight corner handling on loose surface. Like ice.
Click to expand...
Would these generalizations be correct:

Auto is for normal commuting
Auto [+] is for wet/snowy normal driving
Auto [-] is for spirited driving
Lock is for deep snow/sand/gravel w/o tight turns
Manual is for everything in between but w/o the aid of the computer

In addition, would you use Lock for a snow-autoX? Is that too tight and you would use Auto [-]?
 
#80 ·
Sabrewings said:
It would be more since lock is maximum force, lol. Auto would at least give the system time to unstress when not sliding around a corner.

There really isn't much difference in stress as long as you're not on tarmac. It all comes down to how it handles. I've experimented with it, and I see not much use for it outside of slow tight corner handling on loose surface. Like ice.
Click to expand...
I was really referring to the computer, just not to overwhelm. I'm sure it doesn't matter though.
 
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