[FunRevn]

I have the LSD and I as I noted in a previous post and as one of the posters here stated, the e-Diff on the M235 is very very good. My feeling is that if you are not tracking or driving very aggressively on the street you will NOT feel the advantages of the MP Diff.

Yes it is a bit more predictable and smoother versus the e-diff in some situations but it is not really worth the expense unless you are tracking the car. I don't know what the M-team did but that stock e-Diff is impressive. And as stated, you will only really get the most benefit from the MP Diff when DSC is turned OFF (hold for 5 sec).

I only got it because of a special situation and my EGO wanted to feel like we were back in our old M3

[moldcad]

OK, how about DTC on - will it not suffice for the mechanical LSD to intervene before eDif? After all, DTC on allows for considerable forward spin, while still preventing stability loss... Because if entire DSC must be off for LSD to act, the latter really is of no use in other than track driving.

[moldcad]

Here is an excerpt from the official, BMW M-P LSD product leaflet:

"– Whether it's rain, snow or dry conditions – traction is
improved for any type of road condition. When
the driver deactivates all control systems (display: DSC
deactivated/DSC off), careful driving is required in wet and
snow conditions and is only recommended for closed areas"

Dear God, how can they be so vague! It's worded as if using (read: taking all advantage of) the LSD indeed depended on DSC being off, but it is not stated so (or otherwise) clearly enough...

[david.orr]

Originally Posted by moldcad

So, I've made up my mind and have an M235i on order (was debating between that and the 435i, and decided that even coming from an F10, the 4 is still too large for my specific purposes).

Now seeking advise on whether to spend some of the money I saved by not buying the 435i on the LSD. I'm a sporty driver (I think getting rid of otherwise great, but for me - underpowered, 528xi can give you the idea of the way I like to drive), and for over 43 year now - with the exception of the last 2 years - I've been driving RWD cars. Only the last one of those (my old good E46 330i) offered the now obvious electronic "nannies" (and not just the obvious ones like DSC/DTC, but also brake-based e-diff); with my previous RWD cars everything was being taken care of by myself (I do hope I still have the reflexes and muscle memory I learned then).

However - even with e-diff - I remember embarrassing moments when I just couldn't move my 330i from a standstill (like at traffic lights) when both rear wheels were standing on ice (additionally, I didn't have a clutch with that one - it featured the infamous SMG gearbox - so I couldn't use the traditional way of rocking the car and getting it out of being stuck).

My M235i is going to be a SAT car (I did think of a "full return to the basics" and ordering 6MT, but after surgeries my right arm is so weak I can't use it for shifting for too long without a serious fatigue, so I've given up on that; this means no traditional clutch again ).

So, now a question to those savvy and experienced with the BMW 30% LSD available for the M235i: apart from its obvious advantages in track use, will it also help with traction on snow thereby helping somewhat to get used again to RWD after 2 years of the "AT + xDrive laziness" I indulged with my F10?

Please try to take my question seriously, and answer candidly using technical argumentations and terminology (as an engineer, I'm prepared to understand). Unfortunately, here in Poland there is absolutely no chance of a test drive an LSD-equipped car like the 2 series... So - considering I will probably never track my M235i, and only use LSD-assisted drifts and power-exiting corners sporadically - is it worth the price also as a sort of making for the lack of AWD in wintery conditions (OK, OK, good winter tires are the most important )?

Thanks for any constructive input!

I haven't read the other replies but irrespective suggest logical step is to get the car without the LSD and if you feel that you need one after driving your 235 in the conditions you had described, you could always install a LSD thereafter. Apologies if this isn't helpful

[moldcad]

Originally Posted by FunRevn

I have the LSD and I as I noted in a previous post and as one of the posters here stated, the e-Diff on the M235 is very very good. My feeling is that if you are not tracking or driving very aggressively on the street you will NOT feel the advantages of the MP Diff.

Yes it is a bit more predictable and smoother versus the e-diff in some situations but it is not really worth the expense unless you are tracking the car. I don't know what the M-team did but that stock e-Diff is impressive. And as stated, you will only really get the most benefit from the MP Diff when DSC is turned OFF (hold for 5 sec).

I only got it because of a special situation and my EGO wanted to feel like we were back in our old M3

Thanks for the first-hand opinion. However, that DSC must be turned off to take full advantage of LSD is never stated explicitly, and all such hints (including the LSD leaflet info posted by myself) has been speculation so far. For instance - reading the leaflet excerpt I posted above - you can understand it that way: LSD vastly improves traction in bad condition, so might tempt the driver to turn DSC off. However doing so, you must remember other DSC functions (like maintaining directional stability) are also disabled, so in bad road condition only do it in closed areas, like the track".

Therefore I'd like to ask you as an actual LSD user: if you don't turn DSC off completely (instead, use DTC on for instance, or don't tamper with DSC button at all), and you power- slide through a curve - do you or do you not feel e-diff being faster than LSD and brake your slipping wheel? Or similarly - did you ever find e-diff "fighting" with LSD the "who's faster to stop this spinning wheel" game with DSC on?

Your answer could really help me made a more educated decision; I'm definitely not going to track my car, but also definitely am I a fast driver and - like most of us, RWD bimmer enthusiasts - like to play with the tail of my car

[moldcad]

Originally Posted by jaffa12

I haven't read the other replies but irrespective suggest logical step is to get the car without the LSD and if you feel that you need one after driving your 235 in the conditions you had described, you could always install a LSD thereafter. Apologies if this isn't helpful

Thanks for this reasonable advise; my decision-making problem is I have a nice discount proposal from my dealer only valid if I order LSD along with the car itself. Also - even following your advise - I would like to know for sure what and under which condition the LSD would give me in real-life usage...

[moldcad]

To put my question differently:

Assuming DSC is ON (i.e. in public road traffic), when you press on the gas to power-exit a curve or alike - will e-Diff "be faster" and apply brakes to your spinning wheel, rendering LSD useless?

Or will LSD take upper hand and prevent e-diff from intervening, thus allowing nice slide with uninterrupted power on the rear wheels?

Answering these questions would make it clear whether or not one actually has to turn DSC OFF in order to make any use of LSD...

[Killramos]

Originally Posted by moldcad

To put my question differently:

Assuming DSC is ON (i.e. in public road traffic), when you press on the gas to power-exit a curve or alike - will e-Diff "be faster" and apply brakes to your spinning wheel, rendering LSD useless?

Or will LSD take upper hand and prevent e-diff from intervening, thus allowing nice slide with uninterrupted power on the rear wheels?

Answering these questions would make it clear whether or not one actually has to turn DSC OFF in order to make any use of LSD...

I was always under the impression that the LSD was designed to engage BEFORE ediff. However i do not have anything to back that up. I thought it was in the Mperformance part manual and explained why the LSD does not require software changes.

[///MCFC]

Originally Posted by Killramos

I was always under the impression that the LSD was designed to engage BEFORE ediff. However i do not have anything to back that up. I thought it was in the Mperformance part manual and explained why the LSD does not require software changes.

lolz...

[Killramos]

Originally Posted by ///MCFC

lolz...

Coming from the guy who thinks an LSD will prevent traction control from flashing...

[moldcad]

Originally Posted by Killramos

Coming from the guy who thinks an LSD will prevent traction control from flashing...

Easy - I don't even know what "lolz" means

Interestingly, I got an answer on another forum that e-diff is only active with DSC OFF (which would of course imply it's inactive with DSC on). This is something I never suspected - thought DSC OFF=no electronic nannies whatsoever; what is the truth?

[///MCFC]

Originally Posted by Killramos

Coming from the guy who thinks an LSD will prevent traction control from flashing...

oh the lolz weren't for your ignorance on this topic (which is funny in and of itself) but for your epic climbdown in this thread. carry on!

[moldcad]

Originally Posted by ///MCFC

your epic climbdown in this thread. carry on!

This is called "intelligence" and "insightfulness"

[Bahuba]

Originally Posted by pikcachu

Sport+ is not "traction control off"

there are 3 traction states:

DSC on - mode when you start the car
TC on - 1 touch to the traction button or sport+
DSC off - hold 5 secs the traction button... everything is off

Ok ok, Sport+ = DTC on (optimized traction control - a version of DSC where forward momentum is optimized. Allows better traction on loose ground and limited stability during acceleration and driving around bends). I've been driving BMWs for 15 years and I've never liked their nomenclature around stability and traction control.

[Killramos]

Originally Posted by moldcad

Easy - I don't even know what "lolz" means

Interestingly, I got an answer on another forum that e-diff is only active with DSC OFF (which would of course imply it's inactive with DSC on). This is something I never suspected - thought DSC OFF=no electronic nannies whatsoever; what is the truth?

I don't think that's true. DSC OFF really has no nannies. If that was true and we go with the premise that the ediff engages before the Mperf diff then the Mperf would literally do nothing, not just very little. Nothing.

One of the challenges is isolating the effected of the ediff (which emulates the lsd) from the stability control. One of the times when an lsd would engage is cornering, particularly when you are oversteering the car. The ediff would theoretically let you oversteer the car. The stability control however will use the same mechanism (brakes) to try to straighten the path of the car.

Since we don't have a page in idrive where we can toggle all these different systems on or off it becomes very hard to isolate what is happening.

[moldcad]

Originally Posted by Killramos

I don't think that's true. DSC OFF really has no nannies. If that was true and we go with the premise that the ediff engages before the Mperf diff then the Mperf would literally do nothing, not just very little. Nothing.

One of the challenges is isolating the effected of the ediff (which emulates the lsd) from the stability control. One of the times when an lsd would engage is cornering, particularly when you are oversteering the car. The ediff would theoretically let you oversteer the car. The stability control however will use the same mechanism (brakes) to try to straighten the path of the car.

Since we don't have a page in idrive where we can toggle all these different systems on or off it becomes very hard to isolate what is happening.

I'm only quoting you in case some other post came while I type this As to your points:

1. The guy who maintained ediff only works with DSC OFF has proven with his other post he's confusing DSC with DTC, so this part can be dismissed

2. LSD over-riding ediff when cornering/oversteering, and ediff taking upper hand in case of stability loss would actually be a very good scenario, don't you think?

[ska///235i]

Can we all just get along? :

[Killramos]

Originally Posted by moldcad

I'm only quoting you in case some other post came while I type this As to your points:

1. The guy who maintained ediff only works with DSC OFF has proven with his other post he's confusing DSC with DTC, so this part can be dismissed

2. LSD over-riding ediff when cornering/oversteering, and ediff taking upper hand in case of stability loss would actually be a very good scenario, don't you think?

Depends what you are doing but for street driving yes that's exactly what it should be doing. But oversteering WILL activate stability control (which is more expansive than the diff as it uses the front brakes as well) so really unless you turn it off stability control is king. It will also cut power to drive wheels during oversteering so LSD will never really override stability while enabled unless you have the car in sport+ which allows moderate over steer.

Even in Sport+ it should prevent you from over steering to the point of actually spinning the car which is exactly its purpose.

Ultimately there really is no way to know unless you can see the control system diagram on BMW's DSC system... What the limits are, order of preference etc. (i feel like this post is getting circular, its complicated)

With the nannies on there are lots of things the car can do to keep you out of trouble.

Back to the original topic the LSD gives you an extra tool in low slip situations that performs better than the emulated system. This tool has worked well for me this winter in my opinion

[foamie]

Originally Posted by moldcad

Interestingly, I got an answer on another forum that e-diff is only active with DSC OFF (which would of course imply it's inactive with DSC on). This is something I never suspected - thought DSC OFF=no electronic nannies whatsoever; what is the truth?

The person who gave you the answer probably mis-typed and meant to say "LSD" rather than e-diff. You are on the right course in thinking that DSC OFF=no electronic nannies whatsoever.
My take on this however is we never really know if DSC OFF=no electronic nannies whatsoever since there are multiple layers of "software nannies" that manufacturers can build into their cars which get triggered in certain situations and the only way to prove that the nannies are truly off is when you play with the car at ridiculous (maybe unsafe) levels (hopefully in a track or skidpad). Unless BMW themselves comment on it then we are all in the dark.

I would "assume" (so i could be wrong) that the LSD that BMW offers for the M235i triggers before the e-diff does even with all the nannies turned on since it would be of limited use if that was not the case. Maybe a quick chat with the service guys could get you the answers you need since they should be up to date with this car.
The service people could also turn off the e-diff feature if they were in a cooperative mood, then the LSD never gets interference from the e-diff and it does not affect any other systems (they would not do this for me when I was looking at a twin turbo 135 sometime in about 2008. I wanted to put an aftermarket LSD so I did not buy the car) but I know it can be done (the only reason I could think of is, it might interfere with the activation of DSC).

[moldcad]

Originally Posted by Killramos

[...]unless you turn it off stability control is king. It will also cut power to drive wheels during oversteering so LSD will never really override stability while enabled unless you have the car in sport+ which allows moderate over steer. Even in Sport+ it should prevent you from over steering to the point of actually spinning the car which is exactly its purpose.

And this is exactly what I'm after: assume I'm in a spirited driving mood, but - being on public road - don't want to turn DSC off completely. What I do is switch to Sport+ (essentially just Sport with DTC on), and this allows for limited spin of my rear wheels; this can trigger LSD so I'm even happier but doesn't allow for a 180 which make me feel more confident I don't ruin my new car or kill some innocent good man...

Originally Posted by Killramos

Back to the original topic the LSD gives you an extra tool in low slip situations that performs better than the emulated system. This tool has worked well for me this winter in my opinion

And this is another goal I had in mind when thinking of ordering the LSD, in spite of it's high price: during the last 2 years I only drove AWD cars, so became a little worried about moving from standstill and accelerating on snow/ice after I switch back to RWD. Compared to 41 years of RWD experience, 2 years doesn't seem long - but it made me a comfortably numb (or maybe - at my 60 years - I'm just not that adventurous any more?).

Anyway, you helped me tremendously with your answers; thank a lot!

[moldcad]

Originally Posted by foamie

The person who gave you the answer probably mis-typed and meant to say "LSD" rather than e-diff. You are on the right course in thinking that DSC OFF=no electronic nannies whatsoever.
My take on this however is we never really know if DSC OFF=no electronic nannies whatsoever since there are multiple layers of "software nannies" that manufacturers can build into their cars which get triggered in certain situations and the only way to prove that the nannies are truly off is when you play with the car at ridiculous (maybe unsafe) levels (hopefully in a track or skidpad). Unless BMW themselves comment on it then we are all in the dark.

I would "assume" (so i could be wrong) that the LSD that BMW offers for the M235i triggers before the e-diff does even with all the nannies turned on since it would be of limited use if that was not the case. Maybe a quick chat with the service guys could get you the answers you need since they should be up to date with this car.
The service people could also turn off the e-diff feature if they were in a cooperative mood, then the LSD never gets interference from the e-diff and it does not affect any other systems (they would not do this for me when I was looking at a twin turbo 135 sometime in about 2008. I wanted to put an aftermarket LSD so I did not buy the car) but I know it can be done (the only reason I could think of is, it might interfere with the activation of DSC).

I *assume* the same, but with the LSD price I need to be 100% positive - have already sent inquiry to BMW Poland.

I also agree with you that - even if BMW still claims DSC off is "all nannies go home" - with more and more other brands making it impossible, I think it's probable BMW is just posing to be "one of the last driver's cars" maker, while in fact they leave some last resort electronic protection in case the driver doesn't know completely what he is doing after switching DSC off. But this will not defy the laws of physics, either...

[ska///235i]

Originally Posted by moldcad

Not capable to follow? Change the channel (ar..thread).

Really?

Sure good luck with the lsd decision