retrofit a VDC system in an older car

jf1sf5

jf1sf5

Forum Member
Joined
Aug 5, 2012
Messages
2,089
Location
Switzerland
Car Year
'97
Car Model
Forester
Transmission
Manual
Five years ago, when I installed the rear helical and DCCD I had in mind to retrofit a VDC system in my now old '97 Forester but time has passed and because it already is quite capable offroad, the idea only stayed in a corner of my head.

Now I'm thinking of that again and have a friend that knows a guy building his own rock crawlers with a similar system, I mean torsen diffs and retrofitted ETC (Subaru VDC) so I'll get in touch with him to see if we can do something together on my Forester.

I still believe that it would be the ultimate transmission for our rigs, probably even better than diff locks.
 
good idea. i saw you wanted that back in 2013. so you mean take all that stuff from newer models like 2009 or something and put it in yours ? will it fit ?
so you cant just buy forester that allready have it ? how much all those parts will cost you ?
btw i love VDC on my car. its kinda concept one , one of first that they tested on outbacks back then, but i think its so great combined with my tires and even not so powerfull engine and 4eat .
 
I have a friend that has 2 Outbacks like yours with VDC and VTD he doesn't use anymore and on which I could take some parts before he sends them to the scrap yard...so it will be free ! But the difficult part will be to see if I (more precisely another friend !) can retrofit parts of VDC system, the wheel sensors if different from the ABS sensors and the hydraulic pump to activate the brakes but not all the other sensors like the speed, wheel angle, G force...etc because I don't need them.

If it works out, I would theorically have 3 differential lockers...

As you say, it would probably be easier to get a newer 4EAT Forester ('06-'08) with VTD and VDC but I want to do it another way !
 
what you mean you don't need other sensors ? so how system will work then for you if you will not have some sensors ? and how it will work then for you if no have sensors there.
are you saying you wanna make like manual control of VDC ? is that possible ? i mean l allways thought why noone making some kind chip or something to like make our VDC system like with preloaded positions like to make traction control harder or weaker on wheels.
 
I don't know nothing about electronics so maybe will I have to swap the entire VDC system but if I can only use the braking part of it, it would be enough for my needs.
 
well best of luck to you on that if its possible. or just swap everything whats comes with it then.
wait..friend that has VDC outback and dont use it anymore? so whats wrong with car ? maybe you can fix it and drive it haha. would be easier then swap all parts.
 
No ! I truly think that its possible to retrofit a VDC system in an older car. It could also be a non Subaru module if its easier, will see....
 
i guess if you simply remove everything thats comes with it and move there. but then its very sensitive system. speed ratio by wheels and such is there and calculated by model i guess. problems comes later after you done all and you drive and sudenly its stops to work or something else happens what to do then ? its all sensors and software.
 
You can switch the VDC off manually in your Outback, don't you ? Does your VDC system work by just applying the brakes or does it work with the engine RPM too ?

I am looking for a simple early version that just works by applying the brakes, an inverted ABS system that could work by adding a valve to the hydraulic brake modulator.
 
If you can do it, it would be a big improvement! But it will be difficult to do. Not just fitting the mechanical parts but also doing all the electrical side. Be prepared to have your Foz off the road for some time while you sort out all the bugs
 
I think my version is earliest and its works with brakes and with cutting engine power/ torque. And from sound it doesnt seems like simple revs lowering its sounds like it doing something more in engine it sounds on exhaust weird when that happens like not all cilinders working or something. Like its limits spark or something. So no its not just brakes. And then again its giving more power as needed to everywheel individually when its needed. So for vdc or any traction control to work diffs must be open too as vdc must know what every wheel is doing. Sometimes itnuses just brakes andnsometimes both brakes and engine revs/ torque.
On standard exhaust you might not hear it but on my louder uel you can hear that sound when vdc cuts engine its like its choking it or something, it sounds funny too.
 
Thank you Scalman, I re-looked your videos a few times and effectivily it seems that the spinning wheels are braked first and then the engine looses some revs, probably also because it has to move the wheels having grip.
 
NachaLuva said:
If you can do it, it would be a big improvement! But it will be difficult to do. Not just fitting the mechanical parts but also doing all the electrical side. Be prepared to have your Foz off the road for some time while you sort out all the bugs
Click to expand...

I wouldn't try it if I didn't have my very best friend being a mechanic, and a good one :iconwink:
 
it looses revs but not same as you would lower revs yourself but like its forces engine to loose revs , exhaust doing some weird farting like sounds like petrol is cut or spark or something like that. so its more complicated then just lowering revs. its interesting like is it not enough just brake wheels, but i would think its all done for safety on road at high speed, i think then it would help a lot if you loos control of car and maybe you not braking by instinct so engine brakes for you and trying keep car on road. maybe not so needed offroad but then again it brakes first so if just braking is enough then its not cuting engine power. like you said if brakes not enough then its cut engine, looses power for like moment and then trying to give back power.
would be interesting to see what is that x mode , what it does and is that separate box or its just software written for VDC. you could really make very capable car if you could like wrote separate programs like positions for your VDC like 3 options : light , middle and hard traction control. same as done on land cruisers whats called : multi terrain select. its nothing more then software written for traction control in different levels .
if we could have that would be really awesome. or could put x mode on older VDC cars . :)

if you would like to see wiring for VDC module on legacy 2004. should be same as 2nd gen outbacks VDC. its from page 318
https://schnooze.com/files/legacy_manual/Legacy Wiring.pdf
thats some serious stuff going on there haha ...
 
Good find with the schnoose.com, I'll show it to my friend, will sure help !
 
I have contacted a few persons that could be able to help me with this mod, the answer is it is not possible to use the VDC without all the sensors but we're trying to find another way to make it work and have an idea of how it could be done....
 
Sounds like splitting the hand brake into individual levers for each side would be much easier mod and achieve the same thing - at least on the rear, which is what's really doing all the work when climbing IMO.

Cheers

Bennie
 
I have good idea on how to do it. Just take that outback lift it and drive it with VDC.
 
When climbing a rutted hill with diagonal spin, you can't crawl slowly enough with a Subaru and try to pull the right lever to brake the right wheel. I have already tried but it is not efficient. Maybe should I try harder ?

I like having challenges and try new possibilities, and doing this makes me happy the same as when I go offroad !

Now we are three on the project but it will take some time as we all have a real life, like wife and children...
 
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