LSD80% VS LSD40% M220 "Factory"

[_gonbau]

All LSD’s in the early cars were 80% into the mid 70, then they were 40% thru 84 with multi plate diffs that could be adjusted. Then in 85 they became non adjustable 40%. If you didn’t like the locking value of an early diff you would adjust it, as there were 4 or 5 different adjustment settings. Don’t try to make a mountain out of a mole hill, it wasn’t that complicated. I did a 72 ST some years ago, it had 80% diff. The LSD option was not that common, mostly special order. The dealers I worked for never ordered them for cars they were flooring, thought they were dangerous.

I have just seen this response, and it does not answer my questions. We have observed that in 1972, different LSDs with 80% and 40% could be installed. Does this mean that the factory differentiated them when installing them in the vehicles in some way?


I don't think my question is difficult to understand. While I understand that this topic might be repetitive, in this post we have seen different opinions that have been clarified with documents.


It is known that LSDs were not common, and they were usually requested if the driver wanted better vehicle performance. From my perspective, LSDs could be dangerous. In the case of our vehicle, the second owner, who had an accident, may not have been accustomed to them, leading to the loss of control. I suppose that at that time, installing an LSD was an uncommon upgrade that would have drastically changed the vehicle's handling. However, I am still wondering how the installation of the LSDs was differentiated. These questions may never be answered.
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https://porschecarshistory.com/wp-co...r%20Morgan.pdf

[_gonbau]

Do all vehicles (in 1972) with a Limited Slip Differential come with the handwritten inscription "SP" on their build sheet? I've been quite insistent on this because it seems strange to me that the inscription would be on some vehicles with the M220 and not on others. This has made me doubt, as I've expressed before, the meaning of "SP" handwritten. I've also tried to find information on how the factory installed and NOTATED on the build sheet whether it was a 40% or 80% LSD, but I couldn't find an answer. The only thing I've been told is that "SP" stands for "Sperrdifferential," and my question is... why do we know this? Where does this clarification come from? And why is it emphasized on some vehicles and not on others? Why couldn't "SP" (for example) stand for "Sportausfuhrung"?
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I have raised these questions these days directly to the Porsche Archive.
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These questions were never answered by the Porsche archive

[_gonbau]

I keep trying to find documentary evidence indicating that 'sp' was the abbreviation for 'differential slip limits.' I've seen the image of the label in this post indicating 'SD' instead of 'SP,' so I'm asking again where this explanation comes from, stating that 'SP' is an abbreviation given by the German factory, an abbreviation in German 'I understand'... Is there any document that supports what you're indicating in this post?

[928cs]

You will find SP or SD, for SPerrDifferenzial.

I have also seen, "SPD. 40%" written on a 928 gearbox, of a very special type.

[_gonbau]

I have never seen the handwritten notation of "SD" but the explanation about the other vehicle is worth it I guess! That inscription that you mention... was it made by hand on the construction sheet or are you talking about some report that Porsche provided?

[928cs]

I have never seen the handwritten notation of "SD" but the explanation about the other vehicle is worth it I guess! That inscription that you mention... was it made by hand on the construction sheet or are you talking about some report that Porsche provided?

On the gearbox itself, with a pencil