Syncro Chat: VC's, solid shafts, decouplers, AWD/4WD, etc.

IdahoDoug · Posted: Mon Apr 06, 2015 10:35 am Post subject:

Raoul,

Yes that would do it, however throughout this discussion I have assumed and said as much that this assumes correctly same size tires. Obviously if that is violated, any scenario is possible. Like 33" tires on the left wheels, 25" on right. Like stopping every 10 feet on all curves, jacking up the fronts and taking tension off, and repeating. Like driving w one side tires on the grassy shoulder to let thing slip on curves, etc. Same size tires is a good baseline. Of interest, measure tires with a fabric tape and youll be surprised at the variations of tire circumference.!!
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

WestyBob · Posted: Mon Apr 06, 2015 10:51 am Post subject:

raoul mitgong · Posted: Mon Apr 06, 2015 10:54 am Post subject:

raoul mitgong · Posted: Mon Apr 06, 2015 11:33 am Post subject:

raoul mitgong · Posted: Mon Apr 06, 2015 11:39 am Post subject:

Also, my point as Waldi kindly pointed out, this is infinitely more that zero/always/etc.
Just trying to be accurate because people here often give their credentials and then state absolutes that are not absolutely correct.

-d
_________________
84 Westy with a 2.1 (Groover)
86 Tintop Syncro (Crow)
86 Tintop Syncro to Westy project (Tom Servo)
91 Westy (Only the top 12 inches of this van (a burn victim))

raoul mitgong · Posted: Mon Apr 06, 2015 12:59 pm Post subject:

Continuing on the silly number theme.

If you had a rigid bar 1 mile long, held in place at each end by rigid stops, guess how high that bar would bend if you added 1 foot to its length?
Answer: 44.5' high. (edit, I had mistakenly put 44.5", it is 44.5 feet high, next sentence is still correct.)

8' to the length would raise that bar 126'. (calculated from a constant radius arc)

-d
_________________
84 Westy with a 2.1 (Groover)
86 Tintop Syncro (Crow)
86 Tintop Syncro to Westy project (Tom Servo)
91 Westy (Only the top 12 inches of this van (a burn victim))

IdahoDoug · Posted: Mon Apr 06, 2015 5:09 pm Post subject:

I confess I have absolutely no idea what that means. But a Syncro driving on the road still does not transfer any engine torque to the front wheels under any circumstances without rear wheelspin. Zero. Yes, you can intentionally put mismatched tires on it and cause faster rear rotation - absolutely. But at some point well before zany modifications are suggested, it might be a good thing for understanding the VC system to completely grasp that the Syncro and its VC system have some operating conditions worth knowing about. And a key thing to understand is that if the rear wheels are not rotating faster than the fronts, no torque is transferred to the front wheels. Said another way, if the front wheels are rotating the same speed as the rear wheels (driving perfectly straight), or faster than the rears (anything other than perfectly straight), there is no torque transfer. Ruling out driving straight, and also ruling out not driving straight leaves - well - nothing.

raoul mitgong · Posted: Mon Apr 06, 2015 7:58 pm Post subject:

Just trying to show the relationship between a 1mm larger tire and degree of road curve. One straight mile vs 5288 ft that curves 126 feet off the straight line. Let me know if I am still unclear. Wanting to get on the same page with Jon on curve vs diameter input into the VC.
Nothing zany, anyone doing a 5 wheel rotation would get the same thing. I happen to be doing a 10 wheel rotation. 😃
-d
_________________
84 Westy with a 2.1 (Groover)
86 Tintop Syncro (Crow)
86 Tintop Syncro to Westy project (Tom Servo)
91 Westy (Only the top 12 inches of this van (a burn victim))

IdahoDoug · Posted: Mon Apr 06, 2015 9:51 pm Post subject:

Yeah, it would be interesting to know a typical figure of how much farther the fronts travel than the rears in a typical car's life. I think it would be surprising. If you ponder it for a second, an around town drive would be the highest % of extra front miles due to all the turns, where a freeway drive would be the least. I would have a high % because I go through several roundabouts a day!! A rough formula could probably be worked out.

Interesting. I think you'd have to have a problematic tire size difference to offset it. However, I will admit that I hand measured my Syncro tires and put the smaller ones on the rear in hopes of having earlier VC activation.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

Waldi · Posted: Tue Apr 07, 2015 1:18 am Post subject:

WestyBob · Posted: Tue Apr 07, 2015 7:25 am Post subject:

raoul mitgong · Posted: Tue Apr 07, 2015 8:53 am Post subject:

IdahoDoug · Posted: Tue Apr 07, 2015 9:54 am Post subject:

Wow, you guys are grasping at straws here to "prove" that the Syncro does transmit engine torque to the front wheels under all conditions.

So its rear wheel slippage while driving along a paved road now? Yes - in a purely engineering sense that is also true in the real world, the rear wheels of a rear wheel drive car are slipping vs the pavement under them. In fact, all tires are always slipping in some sense. In cornering there is a "slip angle" of the fronts and one for the rear. Tires are in reality slipping all the time and thats how tire wear occurs.

There could be considered a continuum of vehicles laid out from high slip to low slip for driving wheels. Cars like a modern high performance Camaro, a Lamborghini, a Vette at one end whose 400+ horsepower, stiff tires and stiff suspension yield slippage at freeway speeds just driving along. At the other end would be lower horsepower vehicles. At the extreme further end would be something like the Vanagon with 95hp and its engine weight atop its rear drive wheels and the aerodynamics of a box shifting further wheelspin-preventing weight onto the rear tires.

So, yes the Vanagon like all cars generates real world wheelspin while it drives along on a paved road.

As for the VC heating up on the freeway because of this, I disagree. It is the binding from driving along a normal curved high speed road that is generating BRAKING friction in the VC which the VC dissipates by turning it into VC friction and thus heat.

Heh - great stuff! Getting into the subtleties of vehicle dynamics. I referred to this way back in the thread and now we are there...
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

insyncro · Posted: Tue Apr 07, 2015 12:23 pm Post subject:

Personally Doug, you are out on a limb without any proof, documents, pictures, videos or even a Syncro van in your possession.
You seem to be about the only one holding strong on your position.

Others follow along for a bit, but than delete or edit what they write.

Let's see proof of your stance in reference to a Vanagon Syncro's VC and your own written text doesn't count.

The VC documentation from around the world speaks for itself.

Let's see some proof, not conjecture being repeated, over and over and over.

My standard reply to the pmails I get asking where your proof is, all get the same reply....yawn.

Jon_slider · Posted: Tue Apr 07, 2015 12:55 pm Post subject:

When is agreeing to disagree, like being unable to understand?

Lets try this analogy
The Pope says:
The earth is flat, I can see it with my own eyes.
The sun rises in the East, I can see it with my own eyes.
If your name is Galileo, and you think the Earth is Round, lets agree to disagree..

wait, thats not how it works, Galileo went to prison, not because he did not agree, so much as because he was not understood.

Now lets see if we can fit the analogy to how a VC functions:

The Pope says:
A VC transfers traction, I can feel it.
The Traction makes a syncro All Wheel Drive on pavement, I can feel it.
If your name is iDoug, and you think a VC transfers zero traction without rear spin, lets agree to disagree.

wait, thats not how it works, iDoug is in the Doubt House, not because he did not agree, so much as because he was not understood.

lets either agree to disagree, or agree there is a lack of understanding:

The Earth is not really flat, and the sun does not really rise, because the Earth is not the center of the Galaxy.

A VC does not transfer traction on dry pavement, a Syncro is not really AWD, because it has no center differential.
_________________
My Soapboxes: Inflation; Handling; Gearing; Decoupling; Swepco

insyncro · Posted: Tue Apr 07, 2015 1:10 pm Post subject:

I have understood Doug's position on this topic from day one that he came around here.
Not only do I understand what he is saying, but disagree and have not seen one fact, document, video or analogy that has me feeling that his description of what is going on is true at all.

I am strictly talking Vanagon Syncro parts, not Mitsubishi, Toyota, Audi....Vanagon Syncro.

Proof is in the pudding, not just an unfounded, repeated position in interweb forums.

Let's see some proof to back up these statements.

The only thing flat around here is Doug's argument without any proof.

hans j · Posted: Tue Apr 07, 2015 1:13 pm Post subject:

We should have a test. Gather up two vans that are similar, but different center differentials...

Drive on snow, slush, sand, dirt, pavement, slickrock, beaches, tree stumps, and everything else in the world.

Personally? I don't want to reach over and turn on 4wd when I need it and worry about breaking parts if I have to take a turn somewhere.

I would bet you a case of beer, that I can follow a solid shaft van anywhere with my VC van. And I'll do it without worrying about my front tires creating too much friction, without worrying if I should decouple in order to make the tight turn needed, or if I run into a spot on the canyon highway where the plow dumped a lot of snow melt the night before, right in the middle of a turn coming out of a spot that dumped 6" of fresh snow...

I'll take the VC, coupled, as SDP and VW designed it, even still after 29 years of use...
_________________
1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181

raoul mitgong · Posted: Tue Apr 07, 2015 2:07 pm Post subject:

iDoug, it does get frustrating. These guys have a point. We know you are well educated and worked in the industry and have provided much useful information in this forum on many topics. But on this topic you seem to just have a faith in your beliefs (I'd call you the Pope in Jon's analogy due to that faith) and nothing is going to make you take the time to think it through (perhaps I'm wrong and you have thought it through, but don't share your thought process).

I asked you to comment on a simple mechanical system a few pages back. Ignored. I gave you a detailed real world example, you called it zany and took it to an extreme of 33" and 25" tires to make it go away as if I'm talking nonsense. I am never too old to learn if you have something to teach. If I post, I try to add another perspective, question, data point, or something new. Continuing to post the same thing as you have has got to be frustrating as well. How about digging into some of the questions and proving them one way or another?

-d
_________________
84 Westy with a 2.1 (Groover)
86 Tintop Syncro (Crow)
86 Tintop Syncro to Westy project (Tom Servo)
91 Westy (Only the top 12 inches of this van (a burn victim))


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Syncro Chat: VC's, solid shafts, decouplers, AWD/4WD, etc.
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