madteg
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| posted on 12/5/13 at 05:25 PM |
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LSD viscous oil change, upgrade
Thinking of changing oil as i am going to service the diff, found this on internet.
http://passionford.com/forum/ford-sierra-sapphire-rs500-cosworth/367203-diff-viscous-fluid.html
What do you think should i put toy car oil in my diff.
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minitici
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| posted on 12/5/13 at 06:19 PM |
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Does your existing differential still meet the OEM spec limit of 70Nm+-30 for 1/2 turn in 1 second?
If it does then leave the silicone fluid well alone.
If it is shagged then nothing to loose in trying the 500,000 silicone fluid (in the viscous coupling - not the general differential lubricating oil
that is!)
[Edited on 12/5/13 by minitici]
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snapper
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| posted on 12/5/13 at 06:29 PM |
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Agree with above
It's also not just about the fluid its also about the air bubble In the fluid which has an effect on how the diff works
I know some people pump up the air pressure in the diff and some use a different viscosity buthow do you know it will work?
Viscous diffs are black magic either leave all e or save up for a plate diff which is easier to set up or an ATB which works when you need it
IMHO
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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madteg
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| posted on 12/5/13 at 06:29 PM |
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All i can say is when i start to break traction the diff swaps traction from side to side, this makes the car snake up the road.
Also if i drop down from 5th to third and give it a handful the back of car steps towards the kerb, don't half make you jump.
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minitici
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| posted on 12/5/13 at 07:15 PM |
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quote:
Originally posted by madteg
All i can say is when i start to break traction the diff swaps traction from side to side, this makes the car snake up the road.
Also if i drop down from 5th to third and give it a handful the back of car steps towards the kerb, don't half make you jump.
Check your suspension bushes and rear tracking.........
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madteg
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| posted on 12/5/13 at 07:26 PM |
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Bushes are all new, have put it down to diff.
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britishtrident
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| posted on 12/5/13 at 07:27 PM |
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As minitici posted also add corner weights to your checks.
I would add always be a bit cautious about following advice from a forum where the posts don't inspire much confidence.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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madteg
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| posted on 12/5/13 at 07:34 PM |
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Corner weights have been done, have also tried two sets of coilovers.
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britishtrident
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| posted on 12/5/13 at 09:05 PM |
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If one rear wheel has toe-out it will give very twitchy handling especially on the transitions between braking and power and vice-versa.
Toe-in front or rear stabilises handling although has costs in turn in ultimate grip, tyre wear and rolling resistance.
For road use the front wheels can be very close to parallel as long as there is zero toe-out.
With IRS it is generally better to have more toe-in than at the front.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Litemoth
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| posted on 12/5/13 at 10:32 PM |
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The oil in the diff assembly is just standard ep80/90.
The plate pack within the diff is self contained and has within a set of interleaved friction plates that are coated in a very sticky ...well,
syrup/grease. This was originally designed for a heavy Sierra and doesn't react the same in a lightweight seven and has a habit of
'switching' the drive in a very unpredictable & harsh way. I'm not sure if you can successfully change the grease to improve
this but I understand that different grades of grease are available for the plate pack.
Not for the faint hearted as the plates will take a fair bit of stripping and cleaning.
[Edited on 12/5/13 by Litemoth]
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britishtrident
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| posted on 13/5/13 at 08:06 AM |
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quote:
Originally posted by Litemoth
The oil in the diff assembly is just standard ep80/90.
The plate pack within the diff is self contained and has within a set of interleaved friction plates that are coated in a very sticky ...well,
syrup/grease. This was originally designed for a heavy Sierra and doesn't react the same in a lightweight seven and has a habit of
'switching' the drive in a very unpredictable & harsh way. I'm not sure if you can successfully change the grease to improve
this but I understand that different grades of grease are available for the plate pack.
Not for the faint hearted as the plates will take a fair bit of stripping and cleaning.
[Edited on 12/5/13 by Litemoth]
It isn't anything like grease it is a silicone based "Dilatant fluid" in a dilant fluid the viscosity increases greatly with the
heat generated by the shearing friction of the plates slipping, in effect it progressively sticks the plates together the more slippage occurs.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Litemoth
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| posted on 13/5/13 at 12:26 PM |
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quote:
Originally posted by britishtrident
It isn't anything like grease it is a silicone based "Dilatant fluid" in a dilant fluid the viscosity increases greatly with the
heat generated by the shearing friction of the plates slipping, in effect it progressively sticks the plates together the more slippage occurs.
A semantic point. I wasn't attempting to fully describe the 'substance' within the plate pack, simply distinguish it from the
differential oil that many people believe to be the substance that serves to impinge on the limited slip element which, of course it does not.
The dilatant 'grease', 'goop', 'black smooth peanut butter', call it what you will, works by resisting the strain
and has a rate of movement/resistance relationship (perhaps logarithmic) so the faster you try to move it the more it resists movement and is not
necessarily heat dependent. The technical term is It's 'Rheopectic' like mixing cornflour and water (weird stuff)
It's a bit like this:
http://www.youtube.com/watch?v=Vx2DjGwnd44
Try it for yourself!
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