E36 M3 3.2 evo LSD Diff 3.23 ratio big 210 case

The transmission control unit will not lose the adaptation values upon disconnecting the batteries.
This can only be achieved by deleting the values through diagnostic equipment and, according to the document below (see p23) is recommended upon gearbox, valve body or software change.

BMW gearbox essentials (PDF, 3MB)

It may actually be useful to do this after a diff change with such a large difference in ratios.

This document (forgot about it long ago... ) is an excellent read explaining BMW gearboxes and their inner workings in great detail.

Cheers
Reinhard

Zitat von Argonaut;110511

AFAIK, you can use the case with any crown wheel and pinion set designed to be housed in the big case. ...
@All readers: please chime in and correct/advise ref what CWP sets can be fitted in the long case so that Bern is better advised, thanks!

Hi Jason, I'm working flat out this week but will PM you at the weekend and we can continue this discussion offline. Thanks for advice

Zitat von anguswolfendale;110513

If I disconnect the batteries I understand this will reset the gearbox and then it will "learn" the new style of driving with the 3.91 LSD
.

I didn't do this... after the swap from 2,93 to 3,91LSD i just started the car and
(my autobox was a 5hp30)

Zitat von reinhard;110514

The transmission control unit will not lose the adaptation values upon disconnecting the batteries.
This can only be achieved by deleting the values through diagnostic equipment and, according to the document below (see p23) is recommended upon gearbox, valve body or software change.

BMW gearbox essentials (PDF, 3MB)

It may actually be useful to do this after a diff change with such a large difference in ratios.

This document (forgot about it long ago... ) is an excellent read explaining BMW gearboxes and their inner workings in great detail.

Cheers
Reinhard

Alles anzeigen

Reinhard, thank you for this informative document - I was not aware of the need for deletion of adaptive values - I shall have to find someone local who can do this for me.

Chadderz -- any updates on your swap?

Also, if anyone hears about a 3.15 LSD from a 1988-90 E32.. please let me know.

I'm still talking to Argonaut about his items, but my tech/ knowledge limitations may mean finding a complete large case 3.15 LSD rear diff is a more practical solution.

Nice one thanks I appreciate that, I'm pretty much totally committed to this swap by now and actually getting impatient now

Since this is somewhat related I will ask this question here, mostly due to the adaptations coming up here.

I did the swap from a 3.45 to a 3.15lsd on my M70 850, 4 speed auto.
After this swap I find that the car does not change up to 4th gear before around 85-90kph, while with the 3.45 diff it was much, much earlier.
After my swap I find myself driving around the Norwegian country roads (60-80kph speed limit) mostly in 3rd gear.
3rd gear see me cruising at 2000rpm at 80kph, which is not bad, if I manage to get just above to get it to shift into 4th, and drop down to 80 it will hold 4th gear just over 1500 rpm. in 4th I do 100kph at 2000rpm.
Is this late shift to 4th normal on stock cars with M70 4 speed auto and 3.15 diff?

My main goal was to try to save fuel by doing the 3.15 swap, now it may actually turn out the opposite, I will save fuel when om motorways, basically from 90kph and up, but due to the new gearing I may actually end up using more fuel on smaller roads where the speed typically is 60-80kph. (or I may end up speeding a lot)
Since my car is now using 3rd gear a lot more than before the car actually feels nice and quick despite the diff change.

Running Update.

I have had the gearbox and engine adaptive values reset. The gear changes are MUCH smoother now - it is as if there aren't any - just continuous power, like on a high-torque electric motor! I have to watch it as I'm hitting 100PMH too fast and too easy

Overall driving, both hard and fast around the "twisties" and circa 90 to 99MPH on Motorways - I'm getting 21 to 21.9 MPG with the 3.91 LSD.

The cornering is so much tighter with the LSD (and the CSI sway bars and M5 Thrust Bushes). I really notice that if I have to pull out "sharpish" from a junction, there is no hesitation, whereas previously the gearbox took time to work out best gear and the ASC&T cut/delayed power to ensure traction (which scared the hell out of me on more than one occasion with a Juggernaut bearing down on me!)

I'm really please with this modification.

Zitat von anguswolfendale;111785

Running Update.

I have had the gearbox and engine adaptive values reset. The gear changes are MUCH smoother now - it is as if there aren't any - just continuous power, like on a high-torque electric motor! I have to watch it as I'm hitting 100PMH too fast and too easy

Overall driving, both hard and fast around the "twisties" and circa 90 to 99MPH on Motorways - I'm getting 21 to 21.9 MPG with the 3.91 LSD.

The cornering is so much tighter with the LSD (and the CSI sway bars and M5 Thrust Bushes). I really notice that if I have to pull out "sharpish" from a junction, there is no hesitation, whereas previously the gearbox took time to work out best gear and the ASC&T cut/delayed power to ensure traction (which scared the hell out of me on more than one occasion with a Juggernaut bearing down on me!)

I'm really please with this modification.

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Excellent results Angus

I know most people are skeptical to the "high" RPM with this swap, vel...it's not that high, and it's A LOT OF FUN!!!!!!!!!!!

A bit late to the party but I am currently stuffing a 3.64 visco lock from a E46 M3 into the big case on my '91 850i.

I can confirm that all the internals mating surfaces are of the same dimension. Even the input and output flanges can be carried across. This is a good thing because the GKN visco lock uses non symmetrical output shafts so your equal length shafts will not fit.

You DO need to keep the speedo spider ring however. Unless you just want to chance it with the meshing you'd need to get the shims which are NOT cheap from bmw. Or you can get a diff shop to do it. However car being in Hong Kong means no one has the skill to do it so I did it myself. with the right tools and a lot of care its not that difficult.

I went for a 3.64 because I think it will be a decent compromise between rev and fuel consumption. in any case its a improvement going from the 3.15 open diff.

Naturally I went overboard and got the E90 M5 output flanges (same diff internals as the E46 M3) with bigger flanges to fit the bigger and stronger CSI axle shafts I got on order.

I'm now thinking whether to make a diff cooler a-la CSI with some copper tubing. Does anyone know what's the acceptable operating temp for the diff? I will stick a USB temperature logger on it and see if it gets too hot.