LSD80% VS LSD40% M220 "Factory"

[Jon B]

I Have a slightly off topic tool question for you...

Robert, I sent you a PM.

Jon B.
Vista, CA

[_gonbau]

I am still interested in the SP registration and in the rest of the vehicles that will carry the M220. I've asked it before and I deduce the answer. NOT all vehicles with M220 carried SP marking correct? Can someone explain why in some vehicles yes and in others no? And... what other known vehicles have a handwritten SP? I'd be interested in seeing a picture...

+

https://www.elferspot.com/en/car/por...-1973-1958421/

[gulf908]

OT - would anyone have a spare 'SD" alu tag I could have ?
mine was lost somewhere between 1970 and today . . .

TIA
Dennis

[_gonbau]

No, SP designates limited slip. Late gearboxes had a SP paper tag glued on the top web of the diff case.

is there an image?

[_gonbau]

wow .... due to different documents I am forced to ask. How and where was the installed LSD noted or differentiated? There were no factory records of whether you equipped the LSD at what percentage was it? The percentage must be understood to be related to the year? If in a 1972 COA they tell me LSD, must I necessarily understand that it is 80% moronic? If in a 1977 COA they tell me that I have LSD, I must think that it is moronic at 40%?
Where are these data recorded if they are not present in the construction file? Regarding his image ... wow. Could you tell me where it came from? Thank you.

I keep wondering how the porsche differentiated between 40% and 80% LSD when mounting it in a vehicle. How did the mechanic know what LSD he was "up against"?

[_gonbau]

OT - would anyone have a spare 'SD" alu tag I could have ?
mine was lost somewhere between 1970 and today . . .

TIA
Dennis

a plate of an LSD like this, would indicate the type of %? Does anyone have images of their plates, be it 40% or 80%?

[_gonbau]

This document shows that the LSd built into that vehicle is 60%! that data ... where was it obtained? Was it noted on the sheet next to the options?
Attachment 554067

https://www.early911sregistry.org/fo...der-extensions

How do you extract the percentage of LSD to make the COA? And how was it written down in the vehicle's construction sheet...? It may be a difficult question, but I want to put on the record here that "supposedly" the difference between "Normal" and "80%" LSD is written down somewhere.

[john rice]

I confess there is much interesting data about LSDs in this discussion. I was surprised about the 80% being standard configuration for the earlier 911s. One aspect of this 80 vs 40% situation I believe it actually quite simple. The early 911s didn't have a ton of torque so there wasn't much demand for a limited slip. Note the 80% information applies to "Sport Purpose" [competition] and suddenly the 80% makes perfect sense. If you missed it you may find it of interest that the factory commented to the effect that 40% worked best. It wasn't until the larger displacement 911s that a locking diff was more commonly used. A good portion of 930s came with them. I may have mentioned it before that an 80% was severe when used on the street, but that's a story unto itself. Keep having fun!

[_gonbau]

I confess there is much interesting data about LSDs in this discussion. I was surprised about the 80% being standard configuration for the earlier 911s. One aspect of this 80 vs 40% situation I believe it actually quite simple. The early 911s didn't have a ton of torque so there wasn't much demand for a limited slip. Note the 80% information applies to "Sport Purpose" [competition] and suddenly the 80% makes perfect sense. If you missed it you may find it of interest that the factory commented to the effect that 40% worked best. It wasn't until the larger displacement 911s that a locking diff was more commonly used. A good portion of 930s came with them. I may have mentioned it before that an 80% was severe when used on the street, but that's a story unto itself. Keep having fun!

So, having a slip of 40% in 1972 would be a clue to know if it had a more powerful engine than the "normal" one... I understand that? Seen the manual published earlier by Gled. The question remains as to how to distinguish the LSD that the factory mounts between 40% and 80%. Can someone show the coa of their vehicle equipped with 220? Censored or private? The engines that I have shown in the previous COAs. Would they all be "strong..." engines? Would these all be racing cars?
Apart from this, all the 1972 vehicles (for example) made by the factory with which LSD were they assembled? Did it depend on the engine they put in the vehicle?
and fun yes! But if we all collaborate more, maybe we will come to understand some more things about the Porsche world...

[gled49]

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.