Everything is a compromise

1
Steve,

I am a prototyping engineer with Holden and, amongst other things, I
built all of the Adventra and Coupe4 prototypes, so I have some
knowledge of AWD systems. You will find a lot of information on the
Internet about AWD systems and about the Syncro, but what is
frequently missing is relativity - in our case, the suitability of the
application (the Syncro drive system) to the common use OF EACH
INDIVIDUAL OWNER.

Let me assure you that every aspect of motor vehicle design is a
compromise. There is no such thing as the perfect solution, only the
best solution in a given set of circumstances.

You have now narrowed down your set of circumstances considerably by
stating that a lot of your driving is on gravel roads. Knowing this,
I can state that your best compromise is to have a standard to
aggressive VC. You need neither a decoupler nor a solid drive. This
will best suit your circumstances by applying drive to the front
wheels at all times.

This will produce a balanced handling and a sureity of grip that
cannot be obtained by rear wheel drive only, except in some VERY high
end (ie, very expensive) motor vehicles.

My application is quite different to yours. It is not only
predominately bitumen but also freeway for most of the time. It
therefore makes sense for me to use a decoupler, in the decoupled
state, most of the time. But, when I go bush, I will not use the
decoupler. I want that sureity of all wheels driving. There are
conditions of wet road driving where I would also not use the
decoupler.

A fixed drive (ie, no VC) with a decoupler is the worst solution
because it is applicable to only the very narrowest set of
circumstances. In terms of the compromise that is inherit to every
mortal aspect of motor vehicle design, this is the most limited. In
practical terms, it is the best compromise if you are driving in deep
sand ALL THE TIME, and the worst compromise if you are driving on any
terrain other than deep sand ALL THE TIME.

From what you have now told us, I can say that your best compromise is
a VC, be it normal or aggressive, and no decoupler.

Les Harris
2
Re: [Syncro_T3_Australia] Everything is a compromise Nicely  explained Les. Makes a lot of sense to someone like myself who is not very mechanically gifted but appreciates the qualities of the Volkswagen Syncro. My own bus has a limited differential (whatever that means) with no diff locks, unlike what  most of the Syncro members seem to have.
On asking questions through this group, it appeared that fitting the decoupler might have some problems due to no vacuum lines being present in my non diff lock bus. I couldn’t afford over $2000 for the decoupler not to work, so instead I’ve disconnected to shaft between front and back and carry the shaft around in the back of the bus. I’ll fit  the shaft when I know I’m going bush. Dirty and probable inconvenient at times scrambling underneath, but a lot cheaper. I might install it for in the depths of a Melbourne winter but no need for it just yet in the midst of this fabulous Indian summer.
Once again thanks for the philosophy about AWD.
Perhaps some time in the future you could inform  people like myself the difference between AWD, 4WD and all those other 4 wheel drive combinations.
Regards
Michael


On 13/4/05 6:42 PM, "Leslie C E Harris" <leslieharris@optushome.com.au> wrote:


Steve,

I am a prototyping engineer with Holden and, amongst other things, I
built all of the Adventra and Coupe4 prototypes, so I have some
knowledge of AWD systems.  You will find a lot of information on the
Internet about AWD systems and about the Syncro, but what is
frequently missing is relativity - in our case, the suitability of the
application (the Syncro drive system) to the common use OF EACH
INDIVIDUAL OWNER.

Let me assure you that every aspect of motor vehicle design is a
compromise.  There is no such thing as the perfect solution, only the
best solution in a given set of circumstances.

You have now narrowed down your set of circumstances considerably by
stating that a lot of your driving is on gravel roads.  Knowing this,
I can state that your best compromise is to have a standard to
aggressive VC.  You need neither a decoupler nor a solid drive.  This
will best suit your circumstances by applying drive to the front
wheels at all times.

This will produce a balanced handling and a sureity of grip that
cannot be obtained by rear wheel drive only, except in some VERY high
end (ie, very expensive) motor vehicles.

My application is quite different to yours.  It is not only
predominately bitumen but also freeway for most of the time.  It
therefore makes sense for me to use a decoupler, in the decoupled
state, most of the time.  But, when I go bush, I will not use the
decoupler.  I want that sureity of all wheels driving.  There are
conditions of wet road driving where I would also not use the
decoupler.

A fixed drive (ie, no VC) with a decoupler is the worst solution
because it is applicable to only the very narrowest set of
circumstances.  In terms of the compromise that is inherit to every
mortal aspect of motor vehicle design, this is the most limited.  In
practical terms, it is the best compromise if you are driving in deep
sand ALL THE TIME, and the worst compromise if you are driving on any
terrain other than deep sand ALL THE TIME.

From what you have now told us, I can say that your best compromise is
a VC, be it normal or aggressive, and no decoupler.  

Les Harris









Yahoo! Groups Links
3
Thanks Les,
A lot of very good info. Who supplies VC in AUS? I will
contact Volkspower in Melbourne, 03 9808 6777 or
Derek "derekdrew@rcn.com" in the US, the AUS Dollar is good at the
moment, for some prices.
Thanks
Steve, Geraldton, WA

--- In Syncro_T3_Australia@yahoogroups.com, "Leslie C E Harris"
<leslieharris@o...> wrote:
>
> Steve,
>
> I am a prototyping engineer with Holden and, amongst other things,
I
> built all of the Adventra and Coupe4 prototypes, so I have some
> knowledge of AWD systems. You will find a lot of information on
the
> Internet about AWD systems and about the Syncro, but what is
> frequently missing is relativity - in our case, the suitability of
the
> application (the Syncro drive system) to the common use OF EACH
> INDIVIDUAL OWNER.
>
> Let me assure you that every aspect of motor vehicle design is a
> compromise. There is no such thing as the perfect solution, only
the
> best solution in a given set of circumstances.
>
> You have now narrowed down your set of circumstances considerably
by
> stating that a lot of your driving is on gravel roads. Knowing
this,
> I can state that your best compromise is to have a standard to
> aggressive VC. You need neither a decoupler nor a solid drive.
This
> will best suit your circumstances by applying drive to the front
> wheels at all times.
>
> This will produce a balanced handling and a sureity of grip that
> cannot be obtained by rear wheel drive only, except in some VERY
high
> end (ie, very expensive) motor vehicles.
>
> My application is quite different to yours. It is not only
> predominately bitumen but also freeway for most of the time. It
> therefore makes sense for me to use a decoupler, in the decoupled
> state, most of the time. But, when I go bush, I will not use the
> decoupler. I want that sureity of all wheels driving. There are
> conditions of wet road driving where I would also not use the
> decoupler.
>
> A fixed drive (ie, no VC) with a decoupler is the worst solution
> because it is applicable to only the very narrowest set of
> circumstances. In terms of the compromise that is inherit to every
> mortal aspect of motor vehicle design, this is the most limited.
In
> practical terms, it is the best compromise if you are driving in
deep
> sand ALL THE TIME, and the worst compromise if you are driving on
any
> terrain other than deep sand ALL THE TIME.
>
> From what you have now told us, I can say that your best compromise
is
> a VC, be it normal or aggressive, and no decoupler.
>
> Les Harris
4
Steve,

There are several sources. You can include Bernd Jaeger in Germany
as a reliable source. Joachim (he's the 'uluru' character on the
list) lives in Germany and has direct contact, so Joachim can give
you more information. Bernd is a Syncronut like you wouldn't
believe and has a business that caters for Syncros around the
world.

Joachim and the lovely Jasmin shipped their Syncro to Australia last
year and did a circumnavigation that included Tasmania. Brian Reed
spotted them in Apollo Bay (Vic) and established contact, which is
why they are now on the Australian list and have been accorded
honorary status as Australian Syncronauts.

Les

--- In Syncro_T3_Australia@yahoogroups.com, "stephencriddle"
<criddle@w...> wrote:
>
> Thanks Les,
> A lot of very good info. Who supplies VC in AUS? I will
> contact Volkspower in Melbourne, 03 9808 6777 or
> Derek "derekdrew@r..." in the US, the AUS Dollar is good at the
> moment, for some prices.
> Thanks
> Steve, Geraldton, WA
>
> --- In Syncro_T3_Australia@yahoogroups.com, "Leslie C E Harris"
> <leslieharris@o...> wrote:
> >
> > Steve,
> >
> > I am a prototyping engineer with Holden and, amongst other
things,
> I
> > built all of the Adventra and Coupe4 prototypes, so I have some
> > knowledge of AWD systems. You will find a lot of information on
> the
> > Internet about AWD systems and about the Syncro, but what is
> > frequently missing is relativity - in our case, the suitability
of
> the
> > application (the Syncro drive system) to the common use OF EACH
> > INDIVIDUAL OWNER.
> >
> > Let me assure you that every aspect of motor vehicle design is a
> > compromise. There is no such thing as the perfect solution,
only
> the
> > best solution in a given set of circumstances.
> >
> > You have now narrowed down your set of circumstances
considerably
> by
> > stating that a lot of your driving is on gravel roads. Knowing
> this,
> > I can state that your best compromise is to have a standard to
> > aggressive VC. You need neither a decoupler nor a solid drive.
> This
> > will best suit your circumstances by applying drive to the front
> > wheels at all times.
> >
> > This will produce a balanced handling and a sureity of grip that
> > cannot be obtained by rear wheel drive only, except in some VERY
> high
> > end (ie, very expensive) motor vehicles.
> >
> > My application is quite different to yours. It is not only
> > predominately bitumen but also freeway for most of the time. It
> > therefore makes sense for me to use a decoupler, in the
decoupled
> > state, most of the time. But, when I go bush, I will not use
the
> > decoupler. I want that sureity of all wheels driving. There
are
> > conditions of wet road driving where I would also not use the
> > decoupler.
> >
> > A fixed drive (ie, no VC) with a decoupler is the worst solution
> > because it is applicable to only the very narrowest set of
> > circumstances. In terms of the compromise that is inherit to
every
> > mortal aspect of motor vehicle design, this is the most
limited.
> In
> > practical terms, it is the best compromise if you are driving in
> deep
> > sand ALL THE TIME, and the worst compromise if you are driving
on
> any
> > terrain other than deep sand ALL THE TIME.
> >
> > From what you have now told us, I can say that your best
compromise
> is
> > a VC, be it normal or aggressive, and no decoupler.
> >
> > Les Harris
5
Michael,

The word 'limited' as applied to diffs is part of 'limited slip',
whereby the difference in rotational speeds between the wheels on
the one axle is limited to a low value. A normal diff is
called 'open' if it has no means of limiting the speed difference
that can occur, for example, in hard cornering where the inside
wheel unweights to the point that it can spin.

In earlier times, there was a ferocious device called the Detroit
Locker. It was fitted to the Holden XU1 Torana; it engaged with an
audible bang that could be heard miles away, could be felt by the
driver through his bum, his teeth and the steering wheel, and
frightened the daylights out of most passengers.

There are many ways of achieving such linitation, one of which is by
a viscous coupling, which will allow only a few percent difference
before effectively becoming locked, in that it will not permit any
further difference. The Syncro, as delivered, has a VC interspersed
between the prop shaft and the front diff, and it lives in the front
diff housing. This allows for the various differences which
normally occur in rotational speed between the front and rear axles.

However, it has no control over different rotational speeds between
the front wheels. The standard Syncro drive, therefore, allows for
these normal differences between front and rear axles. But, if both
rear wheels lose traction, the entire drive effort is passed to the
front axle.

Optional extras on the Syncro were both rear and front diff locks.
A diff lock is exactly that. It locks the axle so that no
difference in rotational speed is possible between the two wheels on
that axle. Many Syncro owners have the rear diff lock, but few have
the front diff lock. They don't add a lot to available tractive
effort and, when engaged, make the vehicle next to unsteerable.

Going back to your vehicle, it is improbable (but not impossible)
that it is fitted with a limited slip diff. Can you add any further
details? I am very curious.

Les

--- In Syncro_T3_Australia@yahoogroups.com, Michael Rayner
<mrphoto@i...> wrote:
> Nicely explained Les. Makes a lot of sense to someone like myself
who is
> not very mechanically gifted but appreciates the qualities of the
Volkswagen
> Syncro. My own bus has a limited differential (whatever that
means) with no
> diff locks, unlike what most of the Syncro members seem to have.
> On asking questions through this group, it appeared that fitting
the
> decoupler might have some problems due to no vacuum lines being
present in
> my non diff lock bus. I couldn¹t afford over $2000 for the
decoupler not to
> work, so instead I¹ve disconnected to shaft between front and back
and carry
> the shaft around in the back of the bus. I¹ll fit the shaft when
I know I¹m
> going bush. Dirty and probable inconvenient at times scrambling
underneath,
> but a lot cheaper. I might install it for in the depths of a
Melbourne
> winter but no need for it just yet in the midst of this fabulous
Indian
> summer.
> Once again thanks for the philosophy about AWD.
> Perhaps some time in the future you could inform people like
myself the
> difference between AWD, 4WD and all those other 4 wheel drive
combinations.
> Regards
> Michael
>
>

> >
6
Re: [Syncro_T3_Australia] Re: Everything is a compromise Hi Les

As I stated earlier I’m not technically gifted in these matters. I only have a smattering of knowledge.
The bus I brought was an ex Telstra transporter van with windows all round and build date on the build plate has it as 12/1991 and first registration  in Australia was 06/1992 probable making it one of the last T3’s built. The vehicle has no diff locks at all, with no knobs on the dash for engaging either front or rear diff locks. It just automatically engages the front wheels when it detects slip in the rear wheels or when the “G” gear is selected. Can you tell me what the “G” stands for.
Much thanks  for your eloquence  in description of mechanical matters.
Regards
Michael


On 14/4/05 6:11 PM, "Leslie C E Harris" <leslieharris@optushome.com.au> wrote:


Michael,

The word 'limited' as applied to diffs is part of 'limited slip',
whereby  the difference in rotational speeds between the wheels on
the one axle is limited to a low value.  A normal diff is
called 'open' if it has no means of limiting the speed difference
that can occur, for example, in hard cornering where the inside
wheel unweights to the point that it can spin.

In earlier times, there was a ferocious device called the Detroit
Locker.  It was fitted to the Holden XU1 Torana; it engaged with an
audible bang that could be heard miles away, could be felt by the
driver through his bum, his teeth and the steering wheel, and
frightened the daylights out of most passengers.  

There are many ways of achieving such linitation, one of which is by
a viscous coupling, which will allow only a few percent difference
before effectively becoming locked, in that it will not permit any
further difference.  The Syncro, as delivered, has a VC interspersed
between the prop shaft and the front diff, and it lives in the front
diff housing.  This allows for the various differences which
normally occur in rotational speed between the front and rear axles.

However, it has no control over different rotational speeds between
the front wheels.  The standard Syncro drive, therefore, allows for
these normal differences between front and rear axles.  But, if both
rear wheels lose traction, the entire drive effort is passed to the
front axle.

Optional extras on the Syncro were both rear and front diff locks.  
A diff lock is exactly that.  It locks the axle so that no
difference in rotational speed is possible between the two wheels on
that axle.  Many Syncro owners have the rear diff lock, but few have
the front diff lock.  They don't add a lot to available tractive
effort and, when engaged, make the vehicle next to unsteerable.

Going back to your vehicle, it is improbable (but not impossible)
that it is fitted with a limited slip diff.  Can you add any further
details?  I am very curious.

Les

--- In Syncro_T3_Australia@yahoogroups.com, Michael  Rayner
<mrphoto@i...> wrote:
> Nicely  explained Les. Makes a lot of sense to someone like myself
who is
> not very mechanically gifted but appreciates the qualities of the
Volkswagen
> Syncro. My own bus has a limited differential (whatever that
means) with no
> diff locks, unlike what  most of the Syncro members seem to have.
> On asking questions through this group, it appeared that fitting
the
> decoupler might have some problems due to no vacuum lines being
present in
> my non diff lock bus. I couldn’t afford over $2000 for the
decoupler not to
> work, so instead I’ve disconnected to shaft between front and back
and carry
> the shaft around in the back of the bus. I’ll fit  the shaft when
I know I’m
> going bush. Dirty and probable inconvenient at times scrambling
underneath,
> but a lot cheaper. I might install it for in the depths of a
Melbourne
> winter but no need for it just yet in the midst of this fabulous
Indian
> summer.
> Once again thanks for the philosophy about AWD.
> Perhaps some time in the future you could inform  people like
myself the
> difference between AWD, 4WD and all those other 4 wheel drive
combinations.
> Regards
> Michael
>
>

> >




Yahoo! Groups Links
7
Michael,

Ok, now I am with you. The Telstra Syncros are the base model and
came with the Viscous Coupling. This was not an option, this is
part of the Syncro AWD system, which was designed and manufactured
by Styer-Puch in Austria.

The VC operates as I described. It permits just a few percent speed
difference between the front and rear axles before preventing any
further difference. It is not specific to the G gear (Gelandergang
= terrain gear); it operates independently of the gear/s in use.

Les


--- In Syncro_T3_Australia@yahoogroups.com, Michael Rayner
<mrphoto@i...> wrote:
> Hi Les
>
> As I stated earlier I¹m not technically gifted in these matters. I
only have
> a smattering of knowledge.
> The bus I brought was an ex Telstra transporter van with windows
all round
> and build date on the build plate has it as 12/1991 and first
registration
> in Australia was 06/1992 probable making it one of the last T3¹s
built. The
> vehicle has no diff locks at all, with no knobs on the dash for
engaging
> either front or rear diff locks. It just automatically engages the
front
> wheels when it detects slip in the rear wheels or when the ³G²
gear is
> selected. Can you tell me what the ³G² stands for.
> Much thanks for your eloquence in description of mechanical
matters.
> Regards
> Michael
>
>

> >
8
Re: [Syncro_T3_Australia] Re: Everything is a compromise Thanks for the info Les
Regards  Michael


On 14/4/05 6:58 PM, "Leslie C E Harris" <leslieharris@optushome.com.au> wrote:


Michael,

Ok, now I am with you.  The Telstra Syncros are the base model and
came with the Viscous Coupling.  This was not an option, this is
part of the Syncro AWD system,  which was designed and manufactured
by Styer-Puch in Austria.

The VC operates as I described.  It permits just a few percent speed
difference between the front and rear axles before preventing any
further difference.  It is not specific to the G gear (Gelandergang
= terrain gear); it operates independently of the gear/s in use.

Les


--- In Syncro_T3_Australia@yahoogroups.com, Michael  Rayner
<mrphoto@i...> wrote:
> Hi Les
>
> As I stated earlier I’m not technically gifted in these matters. I
only have
> a smattering of knowledge.
> The bus I brought was an ex Telstra transporter van with windows
all round
> and build date on the build plate has it as 12/1991 and first
registration
> in Australia was 06/1992 probable making it one of the last T3’s
built. The
> vehicle has no diff locks at all, with no knobs on the dash for
engaging
> either front or rear diff locks. It just automatically engages the
front
> wheels when it detects slip in the rear wheels or when the “G”
gear is
> selected. Can you tell me what the “G” stands for.
> Much thanks  for your eloquence  in description of mechanical
matters.
> Regards
> Michael
>
>

> >




Yahoo! Groups Links
9
Les et al,
my first Syncro, also a UK based vehicle had a limited slip diff and
(siezed)front and rear diff locks.
Andy.
10
Hi all,
Just to let everybody know I have recieved a new VC from Derek
Drew, at below AU replacement cost. It took about 3 hours to replace.
Better than I thought. Did the jack up the back wheels test and
bingo, it idled off the jacks. Now I can go to the places I thought I
was in 4WD, but only 2WD, feeling a lot more comfortably.

Steve C



--- In Syncro_T3_Australia@yahoogroups.com, "Leslie C E Harris"
<leslieharris@o...> wrote:
>
> Steve,
>
> There are several sources. You can include Bernd Jaeger in Germany
> as a reliable source. Joachim (he's the 'uluru' character on the
> list) lives in Germany and has direct contact, so Joachim can give
> you more information. Bernd is a Syncronut like you wouldn't
> believe and has a business that caters for Syncros around the
> world.
>
> Joachim and the lovely Jasmin shipped their Syncro to Australia
last
> year and did a circumnavigation that included Tasmania. Brian Reed
> spotted them in Apollo Bay (Vic) and established contact, which is
> why they are now on the Australian list and have been accorded
> honorary status as Australian Syncronauts.
>
> Les
>
> --- In Syncro_T3_Australia@yahoogroups.com, "stephencriddle"
> <criddle@w...> wrote:
> >
> > Thanks Les,
> > A lot of very good info. Who supplies VC in AUS? I will
> > contact Volkspower in Melbourne, 03 9808 6777 or
> > Derek "derekdrew@r..." in the US, the AUS Dollar is good at the
> > moment, for some prices.
> > Thanks
> > Steve, Geraldton, WA
> >
> > --- In Syncro_T3_Australia@yahoogroups.com, "Leslie C E Harris"
> > <leslieharris@o...> wrote:
> > >
> > > Steve,
> > >
> > > I am a prototyping engineer with Holden and, amongst other
> things,
> > I
> > > built all of the Adventra and Coupe4 prototypes, so I have some
> > > knowledge of AWD systems. You will find a lot of information
on
> > the
> > > Internet about AWD systems and about the Syncro, but what is
> > > frequently missing is relativity - in our case, the suitability
> of
> > the
> > > application (the Syncro drive system) to the common use OF EACH
> > > INDIVIDUAL OWNER.
> > >
> > > Let me assure you that every aspect of motor vehicle design is
a
> > > compromise. There is no such thing as the perfect solution,
> only
> > the
> > > best solution in a given set of circumstances.
> > >
> > > You have now narrowed down your set of circumstances
> considerably
> > by
> > > stating that a lot of your driving is on gravel roads. Knowing
> > this,
> > > I can state that your best compromise is to have a standard to
> > > aggressive VC. You need neither a decoupler nor a solid
drive.
> > This
> > > will best suit your circumstances by applying drive to the
front
> > > wheels at all times.
> > >
> > > This will produce a balanced handling and a sureity of grip
that
> > > cannot be obtained by rear wheel drive only, except in some
VERY
> > high
> > > end (ie, very expensive) motor vehicles.
> > >
> > > My application is quite different to yours. It is not only
> > > predominately bitumen but also freeway for most of the time.
It
> > > therefore makes sense for me to use a decoupler, in the
> decoupled
> > > state, most of the time. But, when I go bush, I will not use
> the
> > > decoupler. I want that sureity of all wheels driving. There
> are
> > > conditions of wet road driving where I would also not use the
> > > decoupler.
> > >
> > > A fixed drive (ie, no VC) with a decoupler is the worst
solution
> > > because it is applicable to only the very narrowest set of
> > > circumstances. In terms of the compromise that is inherit to
> every
> > > mortal aspect of motor vehicle design, this is the most
> limited.
> > In
> > > practical terms, it is the best compromise if you are driving
in
> > deep
> > > sand ALL THE TIME, and the worst compromise if you are driving
> on
> > any
> > > terrain other than deep sand ALL THE TIME.
> > >
> > > From what you have now told us, I can say that your best
> compromise
> > is
> > > a VC, be it normal or aggressive, and no decoupler.
> > >
> > > Les Harris