Diff conversions -the rear end question-

[ElGrande]

Hi,

I'm looking/working on an new rear end for my 124 CS0 (2l FI, megasquirt, NA 150hp) for a while now.

I recently got an Volvo 240 1031 rear end but with a relatively long 3.54:1 ratio, also this unit is around 5kg heavier then the 1030 wich I'm also able to get in a 3.73:1 ratio.

My question is, if its a better idea to get a rare Fiat 132 rear end, as it comes with the right bolt pattern 4x98 and I guess also with the correct mounting points for the brakes?!

Another big thing would be the unsprung weight... I read that the Fiat 124 rear end weights around 40kg, the Fiat 132 around 50KG and the Volvo 1030 is around 55 and the 1031 around 60kg... that's 50% more than the stock unit.

In which direction should I concentrate my work on. The eventually lighter and easier to fit Fiat 132 rear end wich is relatively rare to find, or the wide available 1030 or stronger 1031 rear end from Volvo where I would easily find and fit an greater variety of LSDs etc.

Can anybody tell us about their own project?

Cheers

Norbert

[Nut124]

What is the reason for the upgrade?

After breaking 3 diffs over the years in my -78 1800, ~150HP, I installed a russian steel LSD. It is much stronger than the Fiat cast diff carrier. Has not failed yet in some 4-5 years of hard driving. The diffs always broke the same way, in the same spot; the ring gear side inner brg journal snaps off the carrier.

[ElGrande]

That’s exactly what I wanted to do, reinforce the rear end and install a Limited Slip Differential.
Maybe also get a quieter diff…

I heard about the Lada Diffs, but back then they where not that strong (size matters)

To test this, I’ll need the older style Fiat rear end.
Where did you sourced your rear and?

[Nut124]

The russian LSD is made of billet steel vs Fiat cast iron. I have not been able to break it yet.

[ElGrande]

@Nut124: Do you know if only the after 1970 rear ends will fit or also the one before 1970?

Am I right that the Original rear end ist only around 90lbs or less?

[evm1024]

The russian LSD is made of billet steel vs Fiat cast iron. I have not been able to break it yet.

Part number?

I've only broken 1 rear end but who knows about the future. This appears to be an option.

[Nut124]

The russian LSD is made of billet steel vs Fiat cast iron. I have not been able to break it yet.

Part number?

I've only broken 1 rear end but who knows about the future. This appears to be an option.

Auto-Ricambi sells one. I bought mine on eBay years ago but the Ukraine war may have complicated availability. They come w various locking levels.

https://autoricambi.us/limited-slip-dif ... l-1966-78/

Mine:

[evm1024]

Thanks for the AR lead.

My car is an 83 so looks like not an option anyway.

[bobplyler]

*edit*