Lsd id

merdad

merdad

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Hi,

I am sorry for the question aked and answered, but I did try search and couldn't come up with what I needed.

I just picked up a LSD, and it is marked 11/38, so I know it is a 3.45. My question is how can I tell the lock %?

This LSD was unlike the others we saw today. This one had no pins on the cylinder casing of the LSD vs. the other that had four. That type shows on Realoem parts, but not this type.

What is this? and the lock ratio? Pix attached.

Thanks,
Merdad
 

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If it is a stock LSD unit, then the normal lock percentage is 25%. I have only seen higher lock percentages when using an aftermarket unit, like Metric Mechanic or Blanton.
 
Thank you. What I finally found from different models on Realoem was that, this is a ZF Automatic Torque box. there are numbers engraved on the unit that reads:
4061 006 050/L 82298 S40

Some say the AT is better than the regular clutch type, but I just couldn't quite get the concept. Any ideas if this is a good unit, or should I get the other one with the clutches?

Thanks,
Merdad
 
2800 CS and sedan had 40% 3.45 LSDs. They were standard on the sedans, but apparently optional on the coupes, at least on US cars.
 
good thing to know about the early LSDs being 40%.

Any idea what a later 3.45 sideloader lock-up should be: 25% , 40%...?!


thx
shanon
 
The E9 LSD design is a carry over from the New class and was available at first in 25% and later 40% with M10 bolts (as shown here) for the early coupes, ie 2800. As power increased the LSD box and friction disc design was revised and was now available in 25% and 75% with M12 bolts.
 
Lsd

FYI, the number you took from the LSD hub has on the end `S40`, so it is a 40% lock. Only early cars had this, same with 2002`s, but 25% was normal. 75% was never an option for use in a road car. It would not be practical as they have a higher pre-load & produce too much heat. Also have an effect on the handling that is not nice in a road car.

Alex
 
Thank you all for the information. Given all these facts, should I stick with the AT unit, or I should buy the other clutched ones? This is for a regular everyday street use.

Thanks,
 
Lsd

In 35 years of working with BMW`s I had never heard of the ZF automatic torque diff. I think you will find they are the same inside.
Alex
 
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