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  #1  
Unread 13th April 2019, 04:43 PM
tchui tchui is offline
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Default viscous coupling eliminator

i did a search but didnt really get what i wanted.


ive built a foz for offroad rallying, on a budget.



it has all open diffs and I have been on the search for LSD's starting with the rear.


I managed to get a plated one and will install it soon.


for my purpose i think the center diff lock up is more important than the front.


here is my question.


the cars with DCCD offer 50 / 50 lock up as the premium setting for gravel.


would a viscous coupler eliminator or a welded center diff not offer the same characteristic?


I believe a locked center diff but open front and rear would handle terribly. bu not that Ive managed to get a rear lsd i want to send more torque to the rear.



a 20kg center is not an option.


but the fact that these exist suggests that totally locked is not the way to go or was that just the best option before DCCD came along?


thoughts?
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  #2  
Unread 13th April 2019, 05:43 PM
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The 5MT DCCD has a 35/65 torque distribution that can be "locked" 50/50. It has been developped for rally racing on all surfaces.

20kg viscous is more of a gravel specialist so it might meet your needs too.

And how are the HotBits doing on the kenyan gravel roads ?
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  #3  
Unread 15th April 2019, 06:14 AM
tchui tchui is offline
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something in my head said its not a true 50/50 lock. it needs to be slightly front or rear bias to keep handling. like 49/51 or 51/49.


anyway im probably going to give it a shot. im sure i will find a burnt out unit somewhere to play with.


hot bits hmmm to be honest their a good shock and toh is a great guy but i think im asking a lot from them for what im doing.



i think i posted to make sure one is supplied with longer canisters as the pressure build up is a lot given the extended stroke.


other issue is the shafts are 22mm outer and then hollowed out for rebound adjustment.


ive had a leak due to top cover not being tight enough on assembly and a bent shaft.


bent shaft has not caused a leak yet although its pretty bent, this is the reason I did not go inverted other than price, but now i may have to for the strength.



these issues are due to the overall length of the shocks and the increased lever forces this creates.



Standard length i think toh provides a good economical option for most peoples capability and budget.
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Unread 15th April 2019, 08:04 AM
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The 5MT DCCD is a planetary differential that distributes torque 35/65. There is a clutch pack inside that can vary the torque infinitely up to 50/50. Its not a real locker as the clutch can't hold a huge amount of torque but I have never reached the limit offroad, only on dry bitumen making some tight turns at low speed to test the locking of the clutch pack and the engine usually stalls before the slippage occurs.

As for the HotBits, you are probably, as you say, asking a little too much ! Would be interesting to know if the shaft bent after a jump or a lateral shock or just on normal corrugations while driving fast.
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Unread 15th April 2019, 04:57 PM
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ive had a suggestion to add a friction plate onto the original 4kg unit.


the bend starts on the shaft at he point of normal ride height / extension. no impacts of any sort. front shock. i run a 00 camber. 215/75/15 rubber and sit id estimate 50mm taller than stock.



https://www.facebook.com/Goodtimes4x4/
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  #6  
Unread 16th April 2019, 12:00 AM
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Quote:
Originally Posted by tchui View Post
ive had a suggestion to add a friction plate onto the original 4kg unit.


the bend starts on the shaft at he point of normal ride height / extension. no impacts of any sort. front shock. i run a 00 camber. 215/75/15 rubber and sit id estimate 50mm taller than stock.



https://www.facebook.com/Goodtimes4x4/
there's a bloke in Aus who refurbs viscous diffs.. you can choose a thicker fluid if desired to get a stiffer diff. I don't think you'll be able to just pop in an extra disc, and its a right mess anyway.

Look up corgiwerx on f***book. He may be able to do your diff, (though shipping would be prohibitive), or maybe give you a lead on the source of diff goop.
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  #7  
Unread 16th April 2019, 01:48 AM
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Lucas Automotive in Moorabbin, Melbourne, also recondition centre vLSDs.
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  #8  
Unread 22nd April 2019, 07:39 PM
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Quote:
Originally Posted by tchui View Post
Nice!! Join Subarus Offroad International and post up some of your photos, lots of people will be very interested in this!!

https://www.facebook.com/groups/subarusoffroad/

Quote:
Originally Posted by Ratbag View Post
Lucas Automotive in Moorabbin, Melbourne, also recondition centre vLSDs.
I wonder if they do 20kg units?
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  #9  
Unread 24th April 2019, 05:46 AM
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The fluid is a non-Newtonian fluid. As it heats up, it becomes more viscous. Newtonian fluids become less viscous as they get hotter.

https://en.m.wikipedia.org/wiki/Non-Newtonian_fluid
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  #10  
Unread 24th April 2019, 12:46 PM
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Quote:
Originally Posted by BillyCorgi View Post
The 12kg.f and 20kg.f are made using thicker viscosity silicone fluids
Good news ! This means that its also possible to have better rear Vlsd's as its just matter of silicone viscosity, right ?
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