Decouplers another con?

[syncrosimon]

.Regular as always Simon Actually I said before 8pm so you are actually 2 minutes early... ....

Hi Simon, was also wondering when you would haul along, good to have the "experience" picture ......thought we might have seen you at the latest TRF day near M'hampstead a few sundays ago.......brilliant day/track!

I have a few more weekends off now so should be able to get to a few more TRF events.

Me and my boys just opened up a Devon Green Lane that has not been driven completely for a very long time.

http://youtu.be/6up1mkAvipQ" onclick="window.open(this.href);return false;

Jed decoupled his syncro the hard way (prop off) after wearing his prop out using 4wd when 2wd would have done. (for his Craotia trip)

[jed the spread]

Jed decoupled his syncro the hard way (prop off) after wearing his prop out using 4wd when 2wd would have done. (for his Craotia trip)

Does the prop stop turning round when you take it out of VC activated 4wd with a decoupler while driving around?

Good news on the lane wouldnt mind hearing more about what went on there, how about a thread about it and how it was done

jed

[syncrosimon]

No it does keep turning, but there is no power being transmitted, so like the internals of a wind up clock, it will run for a good deal longer.

It is exactly for those long trips that the decoupler is such a good thing to have, for that unexpected puncture where you have to put a new tyre on an axle upsetting the rolling radius, for keeping the peky fron CV joints happy, for easier roadside maintenance ie you can spin the wheels to identify problems, for less transmission wind up.

I am not saying that you have to have a decoupler, it just makes life easier and happier on long trips especially.

[jed the spread]

The prop would have had to come off anyway then in my case as the UJ was shagged and can hardly turn on one of the directions causing massive vibrations when turning. All the same parts of the prop are moving if it is decoupled or not so in my case having a decoupler wouldnt have made my life any easier and the prop would have had to come off if I had one or not.

Outcome = decoupler not needed.

jed

[syncrosimon]

But do you not see that an unstressed prop is less likley to go breasticles up, as it is just spinning without trying to put 80hp to the front when not needed.

You just eliminate any drivetrain vibe with a decoupler.

[syncrosimon]

For instance I went to the South of France in 1995 in a 1.9 DG standard syncro. We suffered two flat tyres and had real difficulty finding a suitable tyre to the Michelin XM+S tyres fitted as standard. We just had to buy two new tyres, and the garage put them both on the back, as you would. This then cooked the VC all the way back home. So a de-coupler is the answer. It is I am afraid just better to have one. There is no question that it is a good thing to have on a syncro. The VC was never the same again.

If you want to take the chance of cooking your VC in that situation then fair do's, but I dont.

What do you think of the other benefits I mentioned Jed. Lets discuss them sensibly, after all we are not show off's in the play ground now are we.

[jed the spread]

Anyway if your beloved VC is working right then the van is 95% rear wheel drive on the road,

If your figures are true with 5% of the the drive is going to the front wheels (it will be helped along with the free turning of the drivetrain too so more like 3% in real terms but I am no expert) it isnt enough to wear out the UJ's on a prop, no way. What about front engined cars with rear wheel drive they go for hundreds of thousands of miles with 100% of the power going down a prop..... and when I do get the full whammy through my prop that is when my 4wd is engaged and is needed when the back wheels spin, or when in your case you would be pulling the knob on your decoupler.

Same...

When I get some disposable money I might fit one just so I can give an unbiased view as I will have one to say if its a waist of money or not but in my case of removing the prop in Czech Republic a De coupler wouldnt have made any difference. If something isnt any good I will usually be honest despite having shelled out a fortune for it or not. I paid loads for an LPG conversion once and that was rubbish, a compressor fridge though is good etc...

jed

[syncrosimon]

I was speaking to the couple at Vanfest in their 2.1 DJ Syncro, the people who wrote Inshallah the book about the drive out to Iran in a Bay. They just got back from Istanbul in their syncro. They had no problems with their LPG, and many on here run it and are happy with it. Because your experience of LPG was negative it does not mean that that will be, or should be the view of everyone else. They averaged a cost per mile of 30mpg to Istanbul and back. So spending a grand on a good lpg conversion on a DJ is better than many diesel conversions in running cost's and installation costs. As I have said before my dads T4 syncro has a 110,000 mile average of 28mpg on a 102bhp turbo intercooled 5 pot diesel. My dad is 80yrs old and does not like in principle to exceed 3000 rpm. If you have a DJ an LPG conversion is a good one to consider. I have also had an LPG Caravelle, I would not convert my syncro though just based on the extra weight I do not want to add.

The 95% rear wheel drive applies to a syncro with a perfect VC, even sized tyres and driven in a straight line. In my experience of over 120,000 miles in syncros that does not happen very often. When it was new, I could easily have done without one, but now that the bus is 20+ years old I feel more sympathetic towards the old girl and so like the decoupler, and run the van like the other 1,000,000 transporters VW have successfully made that are 2wd. Only one in 20 transporters were syncros, and they all seem quite fine to me, and more sensible in many respects. So a de-coupler it is for me. Plus its fun, and the boys when they were younger were in charge of switching it on and off, which involved them at an early age.

There is an element of fascination with me as well, in that since I first drove a syncro at the Hertfordshire County Show in 1986 I have been fascinated by the missing third light.

I love it, and if you loved something (like big lights and a heavy winch) I would not criticise you just for the sake of it, or just because I dont have them.

[syncropaddy]

But do you not see that an unstressed prop is less likley to go "boobs" up, as it is just spinning without trying to put 80hp to the front when not needed.

But according to you 95% goes through the rear wheels leaving 5% to the fronts (which is plenty to overcome the rolling resistance of the front axle) not a full 80hp!

You just eliminate any drivetrain vibe with a decoupler.

How? The prop is still spinning ..... and it doesn't have to be under load to wear out

[syncrosimon]

I am bored now, I like them which is why I have one, youve never had one so you dont know what you are missing.

[jed the spread]

It wouldn't have made a differance to me taking my prop off though

jed

[toomanytoys]

Yeah thats it............ "must be the decoupler"........

Nothing to do with trying to jack excess torque through a box never deigned for it.. and then expecting it to haul lots of weight too.. MG is pushing the envelope... And he knows it.... (and IIRC he was running 4.57's not 6.16 and now using 4.86 as he hasnt got any 4.57's left)

IMHO...
VW dropped the decoupler as it was too easy to end up with a reputation for breaking boxes.. (from numpty drivers) and fitting a decoupler with a VC to prevent that was costly and a little over the top for an "off the shelf" production vehicle.. (lets face it, they could have even left the diff locks off in reality but maybe Steyer Puch knew the value early on and it got signed off) ... using a torsen was gonna cost and would mean a major redesign to the box and prob wouldnt have fitted the chassis.,.. A VC was a new, simple and relatively cheap answer to the problem...
Well thats what I would have done from an engineering/commercial point of view...

Choosing to fit a decoupler is a matter of personal choice and what each individuals use and application....... Period...
We all use ours in different ways and with more gusto than VW ever thought would happen...

[KarlT]

Shall I enter the fray?

I got one, Money isn't really an issue, so will give unbiased review.
Haven't had time to use it yet though. Guy has just phoned tonight, to say mew head gaskets/belts are fitted/coolant all bleed up & oil flushed/changed on my 2.5 sumo......Sweeeeet!!! Soooooo excited!!!!

From my experience of driving syncros every other day or so, for the past 6 years.................,
Like/love the way a VC feels for everyday driving, round town, wet A/B roads, but I am also very aware of drive system wind-up on long-fast-hot runs (isn't everyone? )
This is when I see me using the 'new' De-coupler. When you're up to speed & cruising (80mph with the scooby???). Doesn't that make sense?

Wind-up & tightness cannot be good for CV, Props, boxes or forums!!

[torchy]

......... and the garage put them both on the back, as you would. This then cooked the VC all the way back home. So a de-coupler is the answer. It is I am afraid just better to have one. There is no question that it is a good thing to have on a syncro. The VC was never the same again.

If you want to take the chance of cooking your VC in that situation then fair do's, but I dont.

What do you think of the other benefits I mentioned Jed. Lets discuss them sensibly, after all we are not show off's in the play ground now are we.

Just to understand this would it not have been better to have put them on opposite corners so the rolling radius would have stayed the same?

....and if you have to put only one spare tyre on with a deeper tread than the rest would not the diff on that axle take up any difference in rolling radius so they stay the same between the front and back axle?

[KarlT]

......... and the garage put them both on the back, as you would. This then cooked the VC all the way back home. So a de-coupler is the answer. It is I am afraid just better to have one. There is no question that it is a good thing to have on a syncro. The VC was never the same again.

If you want to take the chance of cooking your VC in that situation then fair do's, but I dont.

What do you think of the other benefits I mentioned Jed. Lets discuss them sensibly, after all we are not show off's in the play ground now are we.

Just to understand this would it not have been better to have put them on opposite corners so the rolling radius would have stayed the same?

No, better to drop the prop.