W114/5 Limited Slip Diff

[Driver]

Is there a limited slip diff that will easily fit into a 1974 W115?

[CraigB]

Yes i think anything from 107, 116 and 126 up to 1985 should fit. What engine are you running? Its getting a suitable ratio that might be tricky. You possibly have a 3.69? W107 have 3.46, but can be hard to come by. You might find a 3.07 in a w116 450. A w126 380 can have 3.27. W126 gen 1 500 up to 85 most often have 2.24, which is a really tall ratio even for a v8. Only other one i can think of is 2.47 in a 380sl. And W116 6.9 is 2.65 but probably harder to find.

and that's all to the best of my knowledge but i am not an expert and never fitted it a 114 - but generally I understand most of the suspension etc is same for 114 and 107.

[Giles]

Is there a limited slip diff that will easily fit into a 1974 W115?

May I ask why?

Giles

[Lance]

Good question, a 4 cylinder can't spin it's wheels anyway.

[CraigB]

Haven't you seen those videos of the fire breathing diesels in Europe? They can spin wheels and tear tyres to shreds! My question was based on if something like a V8 was going into the shell. Whatever the engine, getting a diff ratio that suits characteristics of the engine is important.

[Driver]

Good question, a 4 cylinder can't spin it's wheels anyway.

Certainly true Lance but we ar building an endurance rally car and thought it might be nice

[CraigB]

That makes sense to me, in low traction conditions better to have 2 wheel drive vs 1 wheel drive. I remember when i started rallying and got to one not particularly difficult stage and coming across a road block. This was a club level event and came across a wet boggy patch and all these open diff cars were stranded but with our lsd we still managed to drive around them and keep going.

Back to my original question, what engine or what diff ratio in there now and are you happy with it. Then I (and others) can suggest what model cars are likely to have lsd of similar ratio. And its not just a matter of having your gears put into another lsd, with lots of funny little differences.

[Giles]

Good question, a 4 cylinder can't spin it's wheels anyway.

Certainly true Lance but we ar building an endurance rally car and thought it might be nice

Ah, now we're taking. An engine upgrade perhaps?

[John Green]

Is there a limited slip diff that will easily fit into a 1974 W115?

The problem you have is that there was NEVER a factory LSD center that fitted into the small diff housing that the 4 and 6 cylinder car of the era used. V8, well that is another story all together with many different bolt in options available, however you are limited to a ratio no higher than 3.46:1 which I suspect for your car will be an issue.

I have built two custom made LSD diff for competition purposed int he smaller housing. The latest for the P2P car we did two years back. I used a Drexler Motor Sport center which also meant making up custom drive shafts...

[CraigB]

So what is the wheel base, mounts etc of a w107? I thought it was based on W114, but i am guessing that's not the case or you would have done that. But thought i would ask. In your rally car you put the whole antidive set up from memory - was that difficult? I think i have someone keen to take my 107 shell but would have been a shame to send the rear end to the crusher if it was useful. The question is mainly that i don't chuck useful stuff away in the future!

[AMG]

Please have a read of these threads:

viewtopic.php?f=20&t=19694&p=141400

viewtopic.php?f=10&t=10086

viewtopic.php?f=13&t=22257&p=160369

[CraigB]

At first I thought "oh faeces - its all been talked about before and i forgot" but then i read through all the now long posts - quickly though - and the only reference to 114 i saw was that it has the same top hat mount...... but then John is saying it doesn't fit.... I think. Those threads are not focussed on 114 so maybe here for reference we can just talk about 114 lsd, which i know John has done, but doesn't sound as easy as i had thought. Maybe we can amend the heading to put 114 in it too so easier to reference to in future?

[AMG]

iirc, the subframe is not different to R107/C107 isn't it?

that being the case, pre sept 85 107 diffs should be a bolt-in fit, with driveshafts, then again the whole rear subframe assembly should fit should it not?

Not going to be easy finding a short ratio though. 3.46 from a 350SLC. ....

Maybe a w116 centre? halfshafts wont be right though will they....

Just thinking out loud, nonetheless, I'm pretty sure from all that EPC research I did when JG tried this for the w123 P2P car - MOST (not all) of the parts are shared and have 114/5 crossreference numbers on the housings and gears.

[AMG]

At first I thought "oh faeces - its all been talked about before and i forgot" but then i read through all the now long posts - quickly though - and the only reference to 114 i saw was that it has the same top hat mount...... but then John is saying it doesn't fit.... I think. Those threads are not focussed on 114 so maybe here for reference we can just talk about 114 lsd, which i know John has done, but doesn't sound as easy as i had thought. Maybe we can amend the heading to put 114 in it too so easier to reference to in future?

Amended topic.

[CraigB]

I will have a wander and a look in my shed before saying too much more, but maybe the point is that only that 3.46 lsd will fit and from recent experience of JG, very hard to find. I had thought it was the same as gen1 126/116 and while flanges different i thought rest same - but i can check tomorrow.

[AMG]

Have a look under Lurch - because the trailing arms are gen 2 W126 560SEL, with a new rear antiroll bar, I think the early halfshafts are same length as 114/5, but the gen 2 107 ones are shorter because the inner shaft has a flange style CV and the inner stub is held captive in the side gears with circlips.

rear hat on gen 2 housing is offset, front 'ears' are wider and have holes, and not bolts. I think that is it in a nutshell, but happy to be corrected, because I'm not using the reference manual.

[Giles]

https://shop.quaife.co.uk/quaife-merced ... 07-500-slc

One day I will.

Giles

[John Green]

At first I thought "oh faeces - its all been talked about before and i forgot" but then i read through all the now long posts - quickly though - and the only reference to 114 i saw was that it has the same top hat mount...... but then John is saying it doesn't fit.... I think. Those threads are not focused on 114 so maybe here for reference we can just talk about 114 lsd, which i know John has done, but doesn't sound as easy as i had thought. Maybe we can amend the heading to put 114 in it too so easier to reference to in future?

You can bolt up a V* diff to a W114 subframe, not problems, fits straight in. Change the yoke over and then the tail shaft will bolt up. However, you are limited to a 3.46:1 ratio. That's not going to get our friends 230.4 off the line with much ommph... With the P2P car we initially went for a 3.46:1 diff hoping that the power increase to the engine would even out with the diff change from 3.64:1 to 3.46:1 and the increase on tyre rolling diameter. O how wrong we were. Never underestimate how much torque you need to counteract rolling resistance. In the end we went with a 4.08:1 diff which really brought the car alive, but this meant using the smaller 4/6 cylinder housing which then meant customer diff center.

[CraigB]

Yep, so i was on the right track. Any of the bigger centre won't take the shorter gears. There wasn't a straight answer on which engine, but sounds like it might be a 4 cyl and will need a shorter ratio diff. So the answer is no cheap simple solutions for LSD