JoelP
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| posted on 18/12/11 at 07:54 PM |
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which lsd's would work in reverse?
Im thinking about a rear lsd diff to put in the front of a 4x4. It would thus be running i reverse, but i suspect some mechanisms wont work backwards.
Would it be the case that with a jaguar powerlok diff you would only benefit from the preload, as the drive torque which activates it would be
backwards?
Also, would a powerlok diff actually activate in a very low grip situation, such as soft mud?
Cheers!
I want IRS diffs because it would be into a spaceframe axle, thus giving similar clearance to a portal axle. And jag because they must be quite
robust!
Beware! Bourettes is binfectious.
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Ben_Copeland
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| posted on 18/12/11 at 08:42 PM |
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You'd be much better off getting a FRONT diff, subaru perhaps? You can get LSD kits for many front diffs.
Although i'm unsure if they are separate from the gearbox or not
[Edited on 18/12/11 by Ben_Copeland]
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snapper
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| posted on 18/12/11 at 09:08 PM |
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Loads of Sierra 4x4 front diffs on the bay, you have to match front and rear ratios.
The transfer box usually in the tail end of the gearbox some times has a viscous diff
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JoelP
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| posted on 18/12/11 at 09:49 PM |
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trouble is, its incredibly difficult to find an LSD front diff. Scoobies front drive is direct from the gearbox.
Not sure a sierra diff would be up for a 4x4 on large tyres, what with large tyres tending to break drivetrain components.
Beware! Bourettes is binfectious.
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mark chandler
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| posted on 18/12/11 at 10:17 PM |
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Very late XJS's have viscous diff's but pretty rare beast, face lift models not sure if in all them I had a 4.0ltr manual sport that
had.
You will also probally find them post 93 XJ40's
XK8's etc had TC
I doubt that a power lock would work in reverse, what I can tell you is that in slippery conditions they do come in with a bang 
[Edited on 19/12/11 by mark chandler]
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bertie_bas205
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| posted on 19/12/11 at 03:53 AM |
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What 4x4 are you putting it into??
Bertie.
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JoelP
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| posted on 19/12/11 at 08:18 AM |
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quote:
Originally posted by bertie_bas205
What 4x4 are you putting it into??
Bertie.
Any! Hypothetically, it would be onto my own chassis with any nice cab on top. Needs to be an IRS diff to go into a spaceframe axle.
Cheers mark. Powerlok doesnt sound too suitable. Subaru or BMW diffs might be the way forward.
[Edited on 19/12/11 by JoelP]
Beware! Bourettes is binfectious.
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minitici
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| posted on 19/12/11 at 08:53 AM |
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Viscous coupled LSDs or helical (torsen) or Quaife ATB LSDs will work in the reverse direction of rotation.
There is a very slight difference in overall torque bias ratio between forward and reverse with a torsen or ATB but it is neglible.
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Liam
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| posted on 19/12/11 at 09:47 AM |
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A sierra viscous rear diff would work fine running backwards up front. Sierra front diff could be an option but you'd need to find aftermarket
LSD innards as none are LSD as standard. While you're spending time and money finding old/rare parts, there are various options to make it
stronger too, e.g. aftermarket thicker case and a strengthening plate (easy to make yourself that one).
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bertie_bas205
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| posted on 19/12/11 at 08:02 PM |
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Alot of the Jap motors are "diff n shaft" set up, as for light ones.... Vitara or shogun are the only ones i can think of at the mo....
Just to add, they dont run back to front as the transfer box changes the direction of rotation.....
Some of the links below might be of use to ye...
http://forum.difflock.com/viewtopic.php?t=14499
http://forum.difflock.com/viewtopic.php?t=59952&postdays=0&postorder=asc&start=0
Bertie.
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JoelP
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| posted on 19/12/11 at 08:45 PM |
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already read those cheers!
Just to clarify re the diffs, if you took a standard rear diff and put it facing backwards in the front of a vehicle, and drove it from a normal 4x4
transfer box, the wheels would all turn the right way, but the front diff would be effectively running in reverse. (ie, turning backwards, but also
facing backwards, so cancelling out so the wheels all go the same way). This is why i want an LSD that works backwards. People seem to spend a fortune
on locking diffs, which might be worth it, but i want to make a bent spaceframe axle to emulate a portal axle. I know portals would be better since
you can take stress out of the drivetrain by having it geared down at the hubs, but i cant make that stuff without spending a fortune on gears (nearly
a grand from HPC) and accurately machined parts. Simplest way would be to take a jag rear subframe, remove the springs and lock it at full droop with
a longer steel bar, and then mount the entire lot like a normal live axle. But that would be a lot heavier than it needs to be.
Im not sure a sierra LSD would take the stress of low ratio and huge tyres, wasnt the most powerful engine using a 7" diff the 150bhp v6? Maybe
7.5" would be ok.
Thoughts?
Beware! Bourettes is binfectious.
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bertie_bas205
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| posted on 19/12/11 at 09:37 PM |
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quote:
Originally posted by JoelP
already read those cheers!
Just to clarify re the diffs, if you took a standard rear diff and put it facing backwards in the front of a vehicle, and drove it from a normal 4x4
transfer box, the wheels would all turn the right way, but the front diff would be effectively running in reverse. (ie, turning backwards, but also
facing backwards, so cancelling out so the wheels all go the same way). This is why i want an LSD that works backwards. People seem to spend a fortune
on locking diffs, which might be worth it, but i want to make a bent spaceframe axle to emulate a portal axle. I know portals would be better since
you can take stress out of the drivetrain by having it geared down at the hubs, but i cant make that stuff without spending a fortune on gears (nearly
a grand from HPC) and accurately machined parts. Simplest way would be to take a jag rear subframe, remove the springs and lock it at full droop with
a longer steel bar, and then mount the entire lot like a normal live axle. But that would be a lot heavier than it needs to be.
Im not sure a sierra LSD would take the stress of low ratio and huge tyres, wasnt the most powerful engine using a 7" diff the 150bhp v6? Maybe
7.5" would be ok.
Thoughts?
Hmmm, not quite getting what yer trying to do....
The diff still turns the same way front or rear....
To get it to run backwards you'd have to flip it over n run it up side down....
[Edited on 19/12/11 by bertie_bas205]
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bertie_bas205
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| posted on 19/12/11 at 10:07 PM |
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Are ye running both axles off a standard front wheel drive diff/gearbox??
So the drive would be in the same direction rather than in opposite directions like a Land Rover???
Bertie.
P.s, Google "atomic axles"....
[Edited on 19/12/11 by bertie_bas205]
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JoelP
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| posted on 20/12/11 at 12:47 PM |
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I never knew that a land rover front prop turns the opposite way to the rear one! Im sure suzuki transfer boxes have both outputs turning the same
way, when viewed from the same end.
So effectively the scenario im on about is like using a fwd motor sideways in the middle. But, i thought that all transfer boxes were like this
anyway, and i wasnt planning on using a fwd engine and box because you wouldnt have a central diff lock, top speed would be well low, and you wouldnt
have the option of a proper low ratio range.
I would have tried to pick engine, box, transfer box and final drive to give a top speed around 70, with the low ratio range being very low, ie rock
crawler territory.
Beware! Bourettes is binfectious.
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bertie_bas205
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| posted on 20/12/11 at 08:13 PM |
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I couldnt comment on the rice burners (Suzuki) drive train, but i'll find out...
I know anything Land Rover has different directions of rotation....
I'll ask the Zook boys over on Difflock....
I take it ye want the motor to driven on the road?? If its for rock crawling, trust me ye wont want to be doing 70MPH....
Bertie.
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Liam
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| posted on 20/12/11 at 10:58 PM |
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I'm fairly sure I've played with Land Rover oily bits and the front and rear props turn the same way. The arrangement is essentially the
gearbox drives the high/low ratio selection, then that in turn drives a centre diff to the side with front and rear outputs pointing forwards and
backwards respectively, plus transmission brake on the rear output.
Referring to an earlier comment, the 4x4 cossies all used the 7" diff and could be tuned to pretty big power before the 7" would become a
weak point. So bearing in mind I have no idea what you're building I'd say it's likely 7" diffs would be fine. But then again
there would be no real reason not to go for the extra robustness of 7.5"s.
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bertie_bas205
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| posted on 20/12/11 at 11:53 PM |
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Hmmmm, have i been speaking poop then.....???
Bertie.
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stevebubs
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| posted on 21/12/11 at 12:09 AM |
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4x4 version of the BMW 5 series...not sure if they did them with LSD on the front, though..?
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JoelP
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| posted on 21/12/11 at 07:18 PM |
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There is some benefit to using sierra diffs actually, insofar as i know the basics about them, and i could build the axles on the cheap with open
diffs and just fit LSDs as funds allow.
Cheers for the help lads!
Beware! Bourettes is binfectious.
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