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STi V3 Viscous diff v DCCD centre diff

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Old Feb 22, 2012 | 05:10 PM
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Default STi V3 Viscous diff v DCCD centre diff

Hi All,
I think I have got my head around the differences between these. Are the following correct.
STD Viscous unit is a 50/50 split front rear.
DCCD Unit is a 35/65 ish split front rear.
The DCCD unit maintains this 35/65 split despite what setting you set on the dial but allows more or less slip between the diffs. Ie it doesn't send more than 35% to the front but reduces the slip between the diffs.

Fingers crossed I have it right.
Why ? I have installed a DCCD unit in my V3 box for sprinting.
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Old Feb 22, 2012 | 05:36 PM
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I thought DCCD could split front rear from fully open ( 36/65 f-r ) to locked ( 50/50 f-r )

More here http://driveperformance2.subaru.com/.../blueprint.asp

Last edited by DT-SPD; Feb 22, 2012 at 05:38 PM.
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Old Feb 22, 2012 | 09:48 PM
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I think you are both correct - in laymans terms.
Technically speaking, it the DCCD was fully locked and the rear wheels were on tarmac and the fronts were on ice, the split for torque would be more like 95% to the tarmac and 5% on the ice. But to my way of thinking, it would be 50:50.
I have a DCCD on my car and think it is a complete waste of time (ie just another thing to go wrong)- but each to his own I suppose.

Last edited by cster; Feb 22, 2012 at 09:49 PM.
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Old Feb 22, 2012 | 10:02 PM
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Originally Posted by cster
I think you are both correct - in laymans terms.
Technically speaking, it the DCCD was fully locked and the rear wheels were on tarmac and the fronts were on ice, the split for torque would be more like 95% to the tarmac and 5% on the ice. But to my way of thinking, it would be 50:50.
I have a DCCD on my car and think it is a complete waste of time (ie just another thing to go wrong)- but each to his own I suppose.

so in your mind, ...
a designer, engineer who though dccd on a road car is a good option was wrong ?

or was it indeed intended for road use ?
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Old Feb 23, 2012 | 12:47 PM
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the original op has it correct. the torque split remains the same. moving the dial controls the duty cycle of lock between axles just.

Originally Posted by craigo
so in your mind, ...
a designer, engineer who though dccd on a road car is a good option was wrong ?
prodrive removed it from p1 for a reason.
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Old Feb 24, 2012 | 09:06 PM
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Originally Posted by craigo
so in your mind, ...
a designer, engineer who though dccd on a road car is a good option was wrong ?

or was it indeed intended for road use ?
Well I have tracked my car on a good number of occasions wet and dry, with it on and off and can't say I've ever noticed any difference - maybe I'm just a **** driver though.
As far as I'm concerned, it is a bit of a gimmick, but others may have a different opinion.
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Old Feb 25, 2012 | 09:05 AM
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dialing down the DCCD on the track definatley makes a difference in the dry, just keep it in auto in the wet. But maybe i notice it more due to having coilovers dialed up hard with ARBS, ALK and Strut braces. The DCCD definately helps to bring the rear around. But to be honest i tend to leave it in Auto, relying more on the mods above to to neutralize understeer
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Old Feb 25, 2012 | 02:04 PM
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Originally Posted by euan_r
the original op has it correct. the torque split remains the same. moving the dial controls the duty cycle of lock between axles just.



prodrive removed it from p1 for a reason.
abs
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Old Feb 25, 2012 | 02:06 PM
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Originally Posted by cster
Well I have tracked my car on a good number of occasions wet and dry, with it on and off and can't say I've ever noticed any difference - maybe I'm just a **** driver though.
As far as I'm concerned, it is a bit of a gimmick, but others may have a different opinion.
you cant tell the difference?????? does it work on yours.
it makes a big difference , i think the more power youve got the more of a difference it makes
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Old Feb 25, 2012 | 03:17 PM
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Thanks for all your comments Guys, looks like this is a bit of a hot potatoe, just as well that I kept my viscous unit just in case.
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Old Feb 25, 2012 | 06:21 PM
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you`ll love it btw, for better turn in but a bit backend happy all the way back on the thumbwheel, for highspeed stuff i usually have it one notch forward
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Old Feb 25, 2012 | 06:29 PM
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Originally Posted by stedee
you cant tell the difference?????? does it work on yours.
it makes a big difference , i think the more power youve got the more of a difference it makes
gimmick

hmmm on loose surfaces/gravel, it must make a massive difference?
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Old Feb 26, 2012 | 09:35 PM
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Originally Posted by stedee
you cant tell the difference?????? does it work on yours.
it makes a big difference , i think the more power youve got the more of a difference it makes
I think that if you throw the car around a fair bit, it would probably make more of a difference.
Perhaps my driving style is a little too old school (smooth) to derive much benefit.
Then again, maybe my one is buggerred
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