Potential R160 Vacuum Locker - Just one hurdle...

YouTube · Post by **El_Freddo** » Thu Dec 17, 2009 5:29 pm

G’day all,

I’ve been keen to get a rear air locker sorted for my L series subi. One way I had been looking at doing it was to fit an R180 diff and find a locker to fit the R180. ARB don’t make a locker according to their current air locker list… So I did some searching and found this mob: Jack McNamara Differential Specialists The link will take you directly to the page that describes the locker – it actually a vacuum locker but an air unit can be created instead.

I’ve emailed Jack and already had a reply. It’s do-able (YAY! Said I) BUT we’d need 500 ordered to make it happen

The cost of the unit according to Jack is $1000 per unit which I thought was reasonable.

Only real obstacle to this is the 500 units required

Thought I’d share anyway – or has anyone got $500,000 to blow on the purchase of the units

I would like to get a list together of who would want one (or three) but doubt it would be worth the effort as the 500 units seem un-attainable unless the word can be put out there.

Cheers

Bennie

AlpineRaven · Post by **AlpineRaven** » Thu Dec 17, 2009 9:28 pm

:S looks at that price!!! ooh...

not good eh... im sure there is someone else that would make them or can supply them...

Have you considered about getting VLSD or CLSD?
Cheers
AP

Wilbur · Post by **Wilbur** » Thu Dec 17, 2009 9:52 pm

1g is cheap enough I reckon. Have you seen the rrp on most diff locks?

Doubt you'll get 500 people unless you can unleash this request on multi forums...including overseas ones. All the best with it.

AndrewT · Post by **AndrewT** » Fri Dec 18, 2009 12:45 am

yeah unfotunately I don't rekon it's ever going to be a realistic option for an L series diff, the only real solution is to shoehorn in a different kind of diff. After you spend the time/money customising for that you still have the rather large cost of the air locking system. Autolockers also work very well I'm told.
$1000 is just too much.....let's face it, it's about 50% of the value of most entire L series cars!

YouTube · Post by **El_Freddo** » Fri Dec 18, 2009 4:47 pm

Yeah Wilbur if I could get one for $1000 that's pretty much a steal in my book. I'm sure its just a kit to replace the centre and add the actuator but even so. $500,000 for a rear locker is out of the question for me

*dreams about $500,000*

Fair enough on the value of the L comment AndyT - but these units would also fit the lib, foz and outbacks so long as the actuator is located in the right spot. Your Wagon would be a beast with one in the front and rear

The vacuum actuated unit comes with everything required to operate it, dunno about the air unit but I'd agree that the tank/compressor etc would be a side cost.

AP, after the welded there's no way an LSD will do the job! I would like to eliminate the shaft installation and removal plus I'm aiming for the AWD box so will need an open diff on the black top...

I know there's more than 500 offroading subi's out there, but don't know if there'll be 499 of those willing to part with the grand it'll cost...

Cheers

Bennie

fredsub · Post by **fredsub** » Fri Dec 18, 2009 10:53 pm

i still think adding traction control is the way to go for L series
showthread.php?t=526

a ABS unit and custom computer to control its valves and
a speed encoder on the inner CVs, look at the center one in following pic

unfortunately this project stopped with the demise of my Lseries,

Subaman · Post by **Subaman** » Sat Dec 19, 2009 5:53 am

I am sure Brett looked into getting some more of the Detroit style lockers made last year, they were a reasonable price and I think he said they only needed a minimum of 15 to be made. Brett might fill us in a little more.

YouTube · Post by **El_Freddo** » Sat Dec 19, 2009 7:05 am

Interesting Subaman. I thought that pursuit was dead in the water due to its possible behaviour behind an AWD box. That's why I'm very keen on an air or vacuum locker as I can say when I want maximum traction or not.

I wonder if the mob looking at making the detroit could make one of these said units instead? Interesting...

Cheers

Bennie

Post by **yarney** » Sat Dec 19, 2009 8:11 am

We have spoken to the owner of a machine shop about diffs locking and ls he said that if he had sample center they can make what we want.

They can make a r160 lsd work much better than a new factory one so you don't need to have a locker it's good for awd cars

I don't think it was 500 tho Daza might remember numbers and cost

The company makes gearbox parts for v8 supercars maybe i should get him to make me a gearbox so it won't break:rolleyes:

But trying to get people to part with dollars before they get the item is hard plenty of people say yes but when it comes down to the crunch there not around wen you want the money.

Jan

vincentvega · Post by **vincentvega** » Sat Dec 19, 2009 10:03 am

I dont see the point of a locker behind a VLSD center diff. yeah you will have tons of traction at the rear but this will just cause the center to cook and let go.

lockable center AWD box would work nicely though.

Subaman · Post by **Subaman** » Sat Dec 19, 2009 11:09 am

I cannot get my head around how a locker makes any difference to the centre diff,other than to help it, lockers dont give you any "extra" traction, they simply help to stop you losing traction you already have, losing traction , ie: a wheel in the air, which can create large amounts of different wheel speeds between the front and rear of the car would surely heat the centre up sooner, Secondly weather the rear wheels are locked from side to side or not doesnt stop the fact that the front and rear turn at different speeds to each other every time you turn a corner. Detroit lockers unlock when turning corners anyway so no problems there.

Gannon · Post by **Gannon** » Sat Dec 19, 2009 11:40 am

It seems that making a locker is a large and expensive job.

Why not have a group buy of clutch lsd's made to suit the R160.

Hell this Suretrac R160 LSD is only $647 Subaru WRX R160 Rear LSD - AP Racing SureTrac Datsun

discopotato03 · Post by **discopotato03** » Sat Dec 19, 2009 7:45 pm

What a locked differential does is send equal drive to both axles/wheels .
What this means is it won't feed torque to the least path of resistance ie the wheel with the least traction .

This whole idea of any "differential" transfering driving force from a tractionless wheel to another is BS . They transmit something up to equal force to both sides in the hopes that one wheel has as much or more traction than the other .

Something else to ponder is that often a plate LSD or Torsen wont do anything if one wheel has no traction at all ie suspended in mid air .
Your plate LSD won't allow its spider to climb the ramps and load up the plates beyond static pre load .

Roos don't have a lot of suspension travel and jacking them up and fitting big diameter wheels doesn't help because they no longer fit up inside the wheel wells .
Don't laugh but I've seen 4WD trucks with three diff locks diagonally crossed up meaning no traction on a diagonally opposed pair of wheels . It wouldn't move because two of the four wheels didn't have enough grip to drive the thing forwards .
I've driven six wheel drives with five locks , three cross axle/one power divider/one "center" diff lock that couldn't climb rock shelves because all six turning at the same speed still didn't have enough grip .
The most capable I ever drove was an army prototype Leyland Mastill 6x6 and what made it good was very long suspension travel/full set of diff locks/huge 18R 22.5 tyres - more like small earth moving rubber .

Keeping the wheels on terror firma is just as important as limiting wheelspin . Don't know how you do that with short suspension links like ALL subarus have .

Outback bloke · Post by **Outback bloke** » Sun Dec 20, 2009 5:41 am

Roos don't have a lot of suspension travel and jacking them up and fitting big diameter wheels doesn't help because they no longer fit up inside the wheel wells .

Have you ever owned a lifted Subaru with bigger wheels fitted? For someone that seems to be very knowledgeable you know jack shit when I read statements like that. Sure Subarus do have limited wheel travel but in standard form most have open diffs front and rear with some variable and some locked in the centre.

Wheels are going to come off the ground when 4wding.

If you can stop the ones on the ground from doing nothing when the others are off you have a much better chance of forward or backward movement.

This discussion is about trying to find a suitable locking or limiting system for Subarus. Not a comparison between a Subaru and a prototype 6 wheel drive. That is just plain stupid to bring some thing like that in to this topic. If that were the case we should all be trying to convert our Subarus to D9 swamp dozers.

Subaman · Post by **Subaman** » Sun Dec 20, 2009 7:45 am

This whole idea of any "differential" transfering driving force from a tractionless wheel to another is BS . They transmit something up to equal force to both sides in the hopes that one wheel has as much or more traction than the other .

A viscous LSD in the rear practically runs as an open diff when cold, when a wheel leaves the ground nearly all the power is transferred to that wheel, this difference in rotation speeds creates friction iside the VLSD which causes the viscous fluid to get hot,expand and thicken up and then it starts transfering power to the other wheel which is hopefully on the ground.

Gannon · Post by **Gannon** » Sun Dec 20, 2009 8:16 am

Subaman wrote:I cannot get my head around how a locker makes any difference to the centre diff

I think the issue was there seems to be little point spending big money on a locking rear diff if you only have a worn viscous centre diff.

Factory non turbo viscous centre diffs have only 5kg-m of locking force, WRX have 10kg-m and STI's have 20kg-m

Some STI's also had a Torsen LSD in the front diff.

So maybe the best setup might be a STI viscous centre diff, torsen front and tight clutch LSD rear.

Might be a lot more practical and easier to achieve than a manual locking diff. At least it will still be drivable on the blacktop without having to remove driveshafts

And for the L series guys, there was also a thread on the USMB about fitting a STI front LSD to a L series gearbox

twilightprotege · Post by **twilightprotege** » Sun Dec 20, 2009 9:46 am

when i get my ej20 in and the libety dual range box, i'm going to obviously leave the rear stocko RX lsd, i'll also be leaving the stocko centre diff, but then looking at a torsen front diff and see how that goes.

daza · Post by **daza** » Sun Dec 20, 2009 11:02 am

Has anyone tried "shimming" a VLSD?
I fail to understand how an external shim can "preload" a sealed viscus assembly, but it'd be worth the minimal cost if it did.
Link.
Daza.

Subaman · Post by **Subaman** » Sun Dec 20, 2009 11:17 am

I think the issue was there seems to be little point spending big money on a locking rear diff if you only have a worn viscous centre diff.

There would be little point in spending big money on any kind of LSD or locker if your centre diff is stuffed.

Factory non turbo viscous centre diffs have only 5kg-m of locking force, WRX have 10kg-m and STI's have 20kg-m

Some STI's also had a Torsen LSD in the front diff.

So maybe the best setup might be a STI viscous centre diff, torsen front and tight clutch LSD rear.

but wouldnt that cost "big money" too and would put quite large loads on the drive train when driving on the black stuff?

Might be a lot more practical and easier to achieve than a manual locking diff. At least it will still be drivable on the blacktop without having to remove driveshafts

A detroit is an auto locking diff and has already been achieved and you dont have to remove driveshafts to use one.

Outback bloke · Post by **Outback bloke** » Sun Dec 20, 2009 11:34 am

Personally I would simply copy what Brumbyrunner has done to his box and be done with it. If you get stuck with a box like that then you need driving lessons more than you do locking bits.