AWD 12kg Centre Diff LSD

NachaLuva

NachaLuva

Product Developer
Joined
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SE Melbourne
I have been thinking of upgrading my centre diff for a while. Having seen the difficulties & expense of modifying the gearbox with a locking centre, I was thinking a 12kg centre LSD to replace the standard 4kg might be better.

So...I was thinking a group buy might be an idea... :iconwink:

If you're interested or have any info on where is the best place to get them, post here...
 
I recon this mob where Mr T (and Tazza?) etc got their new boxes are probably a good starting point. https://www.subarugearbox.com.au/suba...-terrains.html

Could also try through one of the Japanese parts importers who are members on some other sites I guess, and compare the two for price.

I'd expect several hundred dollars, however think they are an essential part of any gearbox up-grade.
Also have the advantage of being able to be changed over without removing the gear box, so can be 'stage 1' of a progressive improvement. :lildevil:

Oh, by the way, I'm interested! :raspberry:

EDIT: The link above has an error, but will get you to the company's page anyway. I'll fix it later.
 
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Yes Barry is right, it can be done without removing the gearbox.

All Drive Subaroo doesn't do them to the best of my knowledge and if they do they would be expensive. Very good company non the less.
WRX Forums a good place but im sure there would be an importer company that we could go through.
I can look around for some companies and see whats avaliable. The 12kg's are quite easy to come by and can be scored for $300-600 usually.

I am more so keen to get my rear locker in though as this will have a better effect offroad I reckon than a centre diff.
 
I think you might be right Taza- but the centre diff price is lower too. It would be good to do a comparison of standard centre diff & plated rear diff vs 12kg centre diff/standard rear diff.
 
Rally said:
I think you might be right Taza- but the centre diff price is lower too. It would be good to do a comparison of standard centre diff & plated rear diff vs 12kg centre diff/standard rear diff.
Click to expand...
And 12kg centre with rear LSD. :)
Could call it the 'acid test' :poke: :twisted:
 
All Drive Subaroo, located in Sydney, ph (02) 9915 9900
https://www.subarugearbox.com.au/Su...plings-gearbox-transmission-repair-sales.html

Had a good chat to the Norrie from the technical dept. It seems just putting in a heavier centre wont do what we're after, ie, imitating a locking centre.

Apparently as the gel in the viscous LSD heats up, it thickens which reduces torque split to 50/50. As it heats up further, its efficiency drops, allowing more torque to go to a lifted, free spinning wheel.

He said we would get a much greater benefit from plated LSDs front and rear. Also, if properly set up, has good reliability and driveability.

So, a front LSD and rear locker might be a better option...Taza lol :poke:

I'm still going to email my info to him so he can give me quotes on front rear and centre LSDs. I'll let you know the results.

Taza, He said 12kg centres went out of production about 6mths ago, perhaps you can find where to get some.


 
Nachaluva said:
All Drive Subaroo, located in Sydney, ph (02) 9915 9900
https://www.subarugearbox.com.au/Su...plings-gearbox-transmission-repair-sales.html

Had a good chat to the Norrie from the technical dept. It seems just putting in a heavier centre wont do what we're after, ie, imitating a locking centre.

Apparently as the gel in the viscous LSD heats up, it thickens which reduces torque split to 50/50. As it heats up further, its efficiency drops, allowing more torque to go to a lifted, free spinning wheel.

He said we would get a much greater benefit from plated LSDs front and rear. Also, if properly set up, has good reliability and driveability.

So, a front LSD and rear locker might be a better option...Taza lol :poke:

I'm still going to email my info to him so he can give me quotes on front rear and centre LSDs. I'll let you know the results.

Taza, He said 12kg centres went out of production about 6mths ago, perhaps you can find where to get some.
Click to expand...


Well time for me to spill the beans.

My rear locker I am putting in is Phantom Grip. After much research I found that it works the same as a clutch type LSD but has the ability to lock under heavy accelleration. When one wheel is spinning more than the other (ie diaganl but at the rear lets say) it can sense the friction which causes the springs to bind and effectively locks the spider gears. This would be good for a rocky hill climb, mud (where you nearly always have wheels spin) and sand.
After seeing it in action offroad too I was almost sold on it.

I do have my front geared LSD too which will go in but this won't happen anytime soon. I find diagnal spin to me more of an issue than one wheel spin so effectively like Norrie said a F & R LSD are more beneficial.

Taza
 
taza said:
My rear locker I am putting in is Phantom Grip. After much research I found that it works the same as a clutch type LSD but has the ability to lock under heavy accelleration. When one wheel is spinning more than the other (ie diaganl but at the rear lets say) it can sense the friction which causes the springs to bind and effectively locks the spider gears. This would be good for a rocky hill climb, mud (where you nearly always have wheels spin) and sand.
After seeing it in action offroad too I was almost sold on it.
Click to expand...

It says its a 2-way LSD...what does that mean?
Also, does it do anything for rear grip while engine braking going down a hill?
Can you put it in the front or is it rear diff only?

Many questions Taza lol - perhaps best for your locker diff thread :iconwink:
 
Nachaluva said:
It says its a 2-way LSD...what does that mean?
Also, does it do anything for rear grip while engine braking going down a hill?
Can you put it in the front or is it rear diff only?

Many questions Taza lol - perhaps best for your locker diff thread :iconwink:
Click to expand...

It's neither 1way, 1.5 or 2 way to the best of my knowledge as it isn't an actual LSD.

It will work both forward and back. I know for a fact it will go in the rear diff and I am reasonably sure you can get it for the front diff too.

Yes it will work all the time the wheels are spinning, so engine braking it will work.

This is still kinda relevant but could be moved to that thread yes.
 
From what i've heard though having a clutch type LSD in the front and an LSD of sorts in the rear does make the car onroad not as comfortable. Not badly but it is noticable.

Personally I will be doing it though as the compromise is worth it in my opinion.
 
It takes a little while to get used to, but then you don't really notice. In an NA it would be even better. With the front diff, there is noticeable toque steer but only the turbo cars would experience that I'd suspect. And in normal driving anyway it is even less noticeable except in tight, parking type situations. Keep in mind my front diff is helical, not plated so it may be different again
 
Why piss around with a 12lb when you can put a DCCD in there and set the front rear bias to where you want, also 12 & 15kg center diffs are rarer than hen's teeth

Mine is for sale for $700, you'll need the controller but it'll go in without it and give 35f/65rear standard.
 
Barry said:
But don't plated diffs need constant adjusting, so not really suitable for the front?
Click to expand...
Exactly why I sold my new STI plated diff and put the OBX in, also made $1,050 on the deal :raz: and can run ABS and any oil I want, also no clunking every time you go around a corner, you'd never know the OBX was in there.
 
Barry said:
But don't plated diffs need constant adjusting, so not really suitable for the front?
Click to expand...

Yes plated/clutch type do but with Phantom grip it uses springs. These spings can be changed with more heavy duty springs to make it more even with power distribution.

D_Gen, Thats what I have to go in the front of my car.
 
thunder039 said:
i would personally would not have a front LSD, i would rather just have a rear viscous diff, as most of your drive while offroad going up hills etc comes from the rear
Click to expand...

Rear viscous is useless. If you bother putting anything in the rear I would use a clutch type. Its a 20min job to pull the rear diff out if it needs adjusting anyway unlike the front diff.
 
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