The decoupler is not a complicated or expensive device to fit during
I think they wanted to emphasize the full time AWD nature and capabilities
of the vehicle.
or they wanted to make it Idiot Proof, so it could act like 2WD most of the
time, and be AWD the rest of the time. with little input from the driver, or at
least have that capability.
About DeCpouler versus full time AWD with VC -
there is also a Significant Safety Reason to operate in full
time automatic AWD ....
and that is, having the front and rear axles connected mechanically, gives
a natural ABS brake affect.
in 2WD ......on any 4 wheel 2WD vehicle.......if you really get on the
brakes for all they'll deliver ...one end or the other will lock up .
Once some tyres or an axle locks up ..
you've reached the limit of braking that can be attained ...even if say,
the non-locked wheels have traction and could slow down the vehicle more, if
only the other end wasn't locked up.
And of course ... a locked front tyre has no steering ability ....it's just
a 'puck' sliding on a surface..
Many cars have slid right into trees or whatever...
with front tyres locked,. and the driver wasn't smart enough to get the
steering back by letting off the brakes some.
So having one end or the other lock up under heavy braking is a bad thing.
so ...you connect front and rear axles mechanically ...
one end isn't going to tend to lock up under heavy braking, because the
other end is helping to keep things turning on the first end. .
So a syncro in AWD mode is a safer vehicle than it is when in 2WD.
Driving a late model syncro van with Subaru SVX engine that I installed it
, along with freshly rebuilt gearbox with DeCoupler ...
and nicely, you can shift from 2WD to AWD and back, on the fly.
So ...driving on the Interstate Freeway at 70 mph ...about 120 kph
......straight road, dry pavement .......
the van 'felt more stable' in AWD than in 2WD. I'd go back and forth
....yup, felt a little more stable in fast cruise in AWD mode.
So 2WD is less stress on things , and AWD is 'idiot proof' some, and
better under heavy braking ....
'ideally' the VC was supposed to give it the best of both worlds..
a very transparent device that would give AWD with no penalties or
But in the real world the VC gets aggressive after a while
it's rougher on the drivetrain.
tyre size and type have to match very, very well.
You ruin a tire with say, 50K kilometers on the set ...you really should,
or must, get 4 new identical tires. Not just one new one of the same
in modern cars they have accomplished what the VC does with fluids and
plates , with electronics ..
well...now, electronics and drive trains have come so far, that modern
active rear differentials will apply more power to the outside rear wheel coming
out of a curve under power ....never mind systems like Electronic Stability
Lots of electronics are getting between the driver and the tyre
contact patches these days, that's for sure.
the syncro did that without electronics at all, anywhere in the drivetrain,
...just engine management. Maybe cruse control, but nothing electronic about
power distribution, traction, etc. ...pretty brilliant for the era..
and most magically, still valid and capable today as ever !
----- Original Message -----
Sent: Wednesday, April 21, 2010 5:35
Subject: Re: [Syncro_T3_Australia] Re: VC
The lack of a standard decoupler would be a cost issue I'm sure. The
syncros cost a fortune to build I believe
On 22/04/2010, at 10:15 AM, m.mullet wrote:
find it hard to understand why this wasn't a standard item, together with a