[Paulvin]

I installed the M Perf LSD yesterday. Ive read through the BMW LSD FAQ and break in instructions but I’ve got some questions about the procedure: they talk about constant accelerating through left and right turns to actuate the clutch mechanism under load. Does this mean actually getting into a (slight) oversteer situation?

I hope so because I’ve stepped the back out slightly in some turns.

[RvR]

I just drove around circles in a parking lot, 20 clockwise, 20 counter clockwise, then moderately for the next 500 miles, it worked just fine for me. No power oversteer situations for me.

[Pray for Mojo]

Originally Posted by Paulvin

I installed the M Perf LSD yesterday. Ive read through the BMW LSD FAQ and break in instructions but I’ve got some questions about the procedure: they talk about constant accelerating through left and right turns to actuate the clutch mechanism under load. Does this mean actually getting into a (slight) oversteer situation?

I hope so because I’ve stepped the back out slightly in some turns.

You're supposed to drive normally/slightly aggressive, don't hit it hard enough to get the back stepping out until after the break in period. What they don't want is people jumping on the highway and driving the majority in a straight line, which won't activate the clutches.

[dradernh]

Originally Posted by Paulvin

I installed the M Perf LSD yesterday. Ive read through the BMW LSD FAQ and break in instructions but I’ve got some questions about the procedure: they talk about constant accelerating through left and right turns to actuate the clutch mechanism under load. Does this mean actually getting into a (slight) oversteer situation?

I hope so because I’ve stepped the back out slightly in some turns.

It's unlikely you overdid it. If you did, however, you'll know because the diff's clutches will slip in the same way a manual transmission car's clutch does when it needs a rebuild.

BTW, that slipping is always the way you're alerted that your clutch-pack diff is due for rebuilding. Knowing BMW, however, they won't do a rebuild – they'll want to instead sell you a new diff. At that point, you're off to a specialist like Diffsonline here in the States.

Originally Posted by RvR

I just drove around circles in a parking lot, 20 clockwise, 20 counter clockwise

Figure-eights are another means of achieving the same effect.

[msej449]

I'm lucky to live near some natural LSD running-in roads:



These are the sort of curves I imagined the BMW guide was referring to. I'm lucky that this junction is matched by a similar one to the left only a mile or so along the freeway, so I could go back-and-forth easily and do a series of balanced left/right LSD-stretching curves. So worth seeing if there's something similar near you.

[Paulvin]

Originally Posted by msej449

I'm lucky to live near some natural LSD running-in roads:

https://www.sabre-roads.org.uk/wiki/...ne_-_16920.jpg

These are the sort of curves I imagined the BMW guide was referring to. I'm lucky that this junction is matched by a similar one to the left only a mile or so along the freeway, so I could go back-and-forth easily and do a series of balanced left/right LSD-stretching curves. So worth seeing if there's something similar near you.

Many thanks for the responses. I found an isolated car park for some lock turns and figure 8s this morning. Got the standard stares from onlookers.

Unfortunately not blessed natural flowing roads in Perth, and those that are are generally swarmed with traffic police. Bit of a hoon problem in north Perth.

As an aside I had the LCA/TS M upgrade done at the same time as the LSD, and between the two the Control Arm upgrade is my fav of the two. The steering response (maybe also to do with the -1.5deg camber) feels like a totally different car. I’m almost annoyed that BMW would sell the car with the original arms when the M ones are night and day for minimal extra cost. If you haven’t done the control arms definitely consider it.

[Paulvin]

I contacted Drexler directly to ask them their opinion on the matter and got this back. Guess they should know...they built it....


Regarding your question I don't know what BMW recommends but Drexler have always
advised me that the LSD does not require running in, the car can be driven aggressively
straight away.
You should ensure the diff oil is changed periodically, Ravenol SLS SAE 75W-140 GL 5 LS
diff oil should be used with a Drexler LSD.

Friendly regards


Drexler Motorsport Australia
26 North Street Moss Vale NSW
Phone: +61 2 4868 2347

[Phillymb75]

How often should we change the diff oil?

[Paulvin]

Reply from Drexler says every 15000km for spirited road use, reducing if tracking the vehicle.

[Paulvin]

Further info: my dealer wants the car back at 2000km to change out the oil after initial break-in. Strange how none of this is in the LSD FAQ's......

[dradernh]

Originally Posted by Paulvin

Further info: my dealer wants the car back at 2000km to change out the oil after initial break-in. Strange how none of this is in the LSD FAQ's......

1,200 miles for the first oil change sounds right if taking care of the diff properly for the long term is the goal. Especially if you don't have access to a shop qualified to rebuild it when the clutches need refreshing.

Do you know if BMW rebuilds them or plans on selling you a new diff at your first clutch-refresh interval?

[Maynard]

Likely they neuter this info from the instructions to support their 'lifetime fluids' fantasy - strange as this may seem, your dealer is looking out for you. The M2's all get fresh diff oil at the 1200 mile break in service, and I'd always heard to do this for any major machined parts from new (diff, trans, engine). They wear off metal bits that you don't want hanging around (and some situations they also use a break-in lube that is not as slick, to promote wearing-in of contact surfaces).

[Phillymb75]

this is awesome info., thanks! I'm at around 1,200 now, dealer didn't tell me anything about changing the diff fluid.

[Pray for Mojo]

My dealer recommended the 1,200 mile, 2,000km change as well.

[Yak]

Originally Posted by Pray for Mojo

My dealer recommended the 1,200 mile, 2,000km change as well.

my dealer recommended the same and then every 5th motor oil change. they based this on what is recommended for full on M cars.

[msej449]

I have just had a new replacement BMW M Performance LSD fitted after the previous unit developed a fault. The dealer showed me the recommendation from BMW for running-in:

'Break in/servicing differential: Upon differential installation, and fluid top-off, proceed to drive vehicle to a controlled area where several circles/figure-of-eights can be performed. Drive vehicle at idle speed in 20 figure-of-eights, full-lock to full-lock. Then drive at idle speed in 20 full-lock circles left, 20 full-lock circles right.'

They also said to drive moderately for the first 3-400 miles or so, and not over-rev etc.

Note the 'idle speed' recommendation: just engage the engine and don't use the throttle. They emphasised not to go much over a crawl and certainly not anything aggressive.

[dmaxdmax]

Originally Posted by Paulvin

Reply from Drexler says every 15000km for spirited road use, reducing if tracking the vehicle.

That seems very short. OE fluid was 100,000 miles in both e36,46...not sure with F22, but sounds like it's brutal on fluid.

[Nickies]

Originally Posted by dmaxdmax

That seems very short. OE fluid was 100,000 miles in both e36,46...not sure with F22, but sounds like it's brutal on fluid.

I agree with you......... I just figure the previous posters are talking about being on the track everyday or abuse driving conditions most of the time.

This is certainly not justified on a daily driver to service the diff every 15K unless somebody want to waste money on unnecessary maintenance. I cannot find any information in the maintenance book that give some credibility to this.