LSDs - 1 way, 1.5 way, 2 way - what does it all mean?

YouTube · Post by **El_Freddo** » Mon Apr 16, 2012 9:49 pm

As the title asks - Limited Slip Differentials or LSD's - they come as 1 way, 1.5 way and 2 way.

But what exactly does this mean? I'm currently looking into an LSD for a project and thus I'm after info as to what I should get.

It's for a front diff if this makes a difference.

Cheers

Bennie

guyph_01 · Post by **guyph_01** » Mon Apr 16, 2012 11:04 pm

hummmm, Very keen on this. Might copy you:p
What has venom used? do you know what 'way' it is? I'd be keen to get one too but maybe try and eliminate the weird reactions he is having by choosing the appropriate 'way'

d_generate · Post by **d_generate** » Tue Apr 17, 2012 1:46 am

OBX will never need maintenance, won't clunk whereas Cusco, STI etc will need new plates or adjusting probably every couple of years so box apart.

More here.
http://www.club4ag.com/faq_and_tech_pag ... al_101.htm

1-Way, 2-Way, 1.5-Way.......... What Does It Mean?

Some manufacturers make LSD's in different configurations and are commonly classified as 1 way, 2way, and 1.5 way. This designation reflects the design of the cam groove which enables the LSD to function differently under different loads. A 1 way differential means that the cam is shaped in such way as to have positive lock only when accelerating. The 2 way is constructed in a way to have positive lock motion in either acceleration or deceleration. The 1.5 way is a new term used to describe the 2 way cam which enables different lock up rates during the two directional forces. The 1.5 distribute positive lock stronger under acceleration than when decelerating. The 1.5 way can provide more forgiving balance when braking than a full 2 way setup, although it is less effective for true racing applications, it provides easier operation for beginners in throttle off conditions. It is also effective for front drive cars which need extra stability during braking.

guyph_01 · Post by **guyph_01** » Tue Apr 17, 2012 12:15 pm

So for off-road purposes only, Looks like 1 way or 1.5 way would be better? Not really keen to have it lock on braking and deceleration around corners on the road. Maybe 1 way would be best? thats my understanding from what you explained Tom.

On e-bay it seems these quite a few more 1.5 way ones than anything else. and pretty expensive. Hummmm maybe i'll let you Bennie try in out and buy one if its ok once i saved up:p

thunder039 · Post by **thunder039** » Tue Apr 17, 2012 12:36 pm

guyph_01 wrote: Hummmm maybe i'll let you Bennie try in out and buy one if its ok once i saved up:p

let the brave go first

taza · Post by **taza** » Tue Apr 17, 2012 2:12 pm

Im putting in one of these when my gearbox gets done.

http://www.eracingzone.com/product_p/obxlsd39.htm

This is what Venom had and im pretty sure it's 1 way. He says it does more than his rear LSD but that is a clutch type and probably needs adjusting.
I am going to try an auto-locker in my rear when the car gets sorted too. Not sure how it will act with AWD onroad....

d_generate · Post by **d_generate** » Tue Apr 17, 2012 7:13 pm

That's identical to the one I have in mine, a mate and I went up to Lancelin today and got a good 45min on two GoPro camera's (one on the drivers side and one on the roof) plus his video and still camera, from the small amount I saw on his normal camera there are some great shots and video of me going around the side of a huge bowl, diff again was faultless, my son bought one for his WRX track car last week but not in yet.

Gannon · Post by **Gannon** » Tue Apr 17, 2012 8:09 pm

The LSD in that link is a torsen or geared LSD

They have worm gears instead of bevel gears and a difference of torque pushes the gears sideways and provides a limiting effect. They are great for front diffs as they dont provide a limiting effect when there is little torque acting on them, like in carparks, but this also means they are useless when one wheel is off the ground.

YouTube · Post by **El_Freddo** » Tue Apr 17, 2012 9:15 pm

thunder039 wrote:let the brave go first

Well, it's not me then! D_gen and Venom have both gone down this route. From what Venom's told me his is a 1 way. After reading the above that D_gen dropped in about the LSD's "ratings" I'm thinking a 1.5 way is what I want to go with.

taza wrote:Im putting in one of these when my gearbox gets done.

http://www.eracingzone.com/product_p/obxlsd39.htm

That's the unit I'm after! But I was looking at it on fleabayUS. I'll be interesting to see what the postage is going to be.

Gannon wrote:They are great for front diffs as they dont provide a limiting effect when there is little torque acting on them, like in carparks, but this also means they are useless when one wheel is off the ground.

I thought it's been well established that a LSD is useless once a wheel has been lifted.

Thanks for the info D_gen!

Guyph - the "weird" reactions that you're trying to eliminate will still be there as it will naturally handle differently to an open diff, only once you're used to it will it no longer be weird... Clear as mud?

I'm looking forward to this!

Cheers

Bennie

Gannon · Post by **Gannon** » Tue Apr 17, 2012 9:34 pm

El_Freddo wrote: I thought it's been well established that a LSD is useless once a wheel has been lifted.

Both Clutch and Viscous LSDs should transfer torque with one wheel off the ground.

It appears that the factory LSD found in Leone RX and Vortex Turbos is a 2 way.

YouTube · Post by **El_Freddo** » Tue Apr 17, 2012 10:07 pm

Gannon wrote:Both Clutch and Viscous LSDs should transfer torque with one wheel off the ground.

I didn't know that! I think I'll have to keep an eye out for a Viscous LSD for the rear

That'll be a while way due to expense.

Gannon wrote:It appears that the factory LSD found in Leone RX and Vortex Turbos is a 2 way.

Interesting!

Cheers

Bennie

guyph_01 · Post by **guyph_01** » Wed Apr 18, 2012 2:29 am

El_Freddo wrote:Well, it's not me then! D_gen and Venom have both gone down this route. From what Venom's told me his is a 1 way. After reading the above that D_gen dropped in about the LSD's "ratings" I'm thinking a 1.5 way is what I want to go with.

Why the 1.5 over the 1way LSD? You think it will be better than venom's one? Won't it cause more of the 'weird stuff'?

El_Freddo wrote: That's the unit I'm after! But I was looking at it on fleabayUS. I'll be interesting to see what the postage is going to be.

Isn't that a 1way?

d_generate · Post by **d_generate** » Wed Apr 18, 2012 2:46 am

I'm going to have to find a flat piece of ground going to a slight raise and get a trolley jack under front and rear r/h or l/h sides and see if the car will move, probably better leave it until I get the DCCD in there though as everything will just go to the rear spinner with the viscous center and rear.

discopotato03 · Post by **discopotato03** » Wed Apr 18, 2012 10:59 am

Gannon wrote:Both Clutch and Viscous LSDs should transfer torque with one wheel off the ground.

It appears that the factory LSD found in Leone RX and Vortex Turbos is a 2 way.

Clutch LSDs are limited to the static pre load on their plates particularly if the LSD is unloaded when you lift a wheel . Virtually all production clutch LSDs have bugger all preload which stops them chattering and doing silly things in road cars .
The other option , from a diff manufacturers viewpoint , was to alter the ramp angles on the spiders pins to make it clamp up more readily under drive loads . I once had a Nismo H190 LSD and it was set up like that . When you got up it it would virtually lock solid but when cruising around it acted more like an open center . As I said production LSDs are designed to be smooth and quiet and end up not being very effective .
Mitsubishi fitted clutch LSDs in the back of RS Evos and USDM 8s and 9s , they also rejigged the plates so they only half work , best way to shut up people that can't stand LSDs that work properly .
The GSRs like mine get an electronic/hydraulic thing called AYC or active yaw control . Basically its like a conventional clutch LSD with no pre load on the plates at all . It uses hydraulic pressure to vary the loads on these clutches to limit understeer and get you round corners faster . It makes no noise and 99% of the time you would not even know its there .
Personally I'd prefer the lighter stronger RS LSD but at least AYC fails safe and acts like an open diff . Then you rip it all out and bolt the RS stuff in and lose 30 kgs .

A .

taza · Post by **taza** » Mon Dec 10, 2012 10:53 pm

Bringing up this thread again... I'm after a rear clutch type LSD and to shim it up pretty tight. Not to the point of it acting like a locked diff but not far off... After shattering the spider gears in my open diff due to thrashing the car up hills(due to open diffs) I don't really wanna go through another rear diff.
Where is the best place to source one? Anything under $700 I'm willing to pay..
My 4.11 ratios will bolt on though and I can use my diff housing with male rear stub axles?

On another note, while having my rear diff out of my Forester I am still able to drive the car with just the front diff/wheels. It will still move but as soon as you go to accelerate or go up a hill the 4kg centre diff isn't strong enough to keep moving the car. However it is still effective and does work

Gannon · Post by **Gannon** » Tue Dec 11, 2012 4:50 am

taza wrote: On another note, while having my rear diff out of my Forester I am still able to drive the car with just the front diff/wheels. It will still move but as soon as you go to accelerate or go up a hill the 4kg centre diff isn't strong enough to keep moving the car. However it is still effective and does work

That is a sure fire way to ruin your centre diff in a very short amount of time.

taza · Post by **taza** » Tue Dec 11, 2012 9:17 am

Gannon wrote:That is a sure fire way to ruin your centre diff in a very short amount of time.

Why? That means that driving on sand heaps will do the same thing... god I'm over Subaru's, they just can't handle anything. Can't wait to trade in on a real 4wd..

YouTube · Post by **El_Freddo** » Tue Dec 11, 2012 5:53 pm

taza wrote:while having my rear diff out of my Forester I am still able to drive the car with just the front diff/wheels. It will still move but as soon as you go to accelerate or go up a hill the 4kg centre diff isn't strong enough to keep moving the car. However it is still effective and does work

It won't be effective. And as Gannon has said you'll burn out the centre diff. Ok to gently move around the work shop but other than that I'd be leaving it as it is or dropping another open diff in the rear for now.

Also, do you have a two piece tail shaft to leave the front piece in so that the oil doesn't leak out the back of the gearbox?

taza wrote:Why? That means that driving on sand heaps will do the same thing... god I'm over Subaru's, they just can't handle anything. Can't wait to trade in on a real 4wd..

No, driving on sand is different as you have the rear diff in there to create some friction to help the LSD - if you take out the rear drive then yes you'll burn it out in no time and not be able to move your vehicle at all.

Subarus can handle things, many many people have proven this time and time again. I think you're at the point of being unreasonable in your expectations of your vehicle. It's an AWD, not a PT4wd!

I can see you having the same problems with a "real" 4wd, and then complaining about the cost of the repairs that will be at least double of what the cost of the subaru is!

Cheers

Bennie