Question for those who've ordered a 2010 MCS: is it true that you can't get the mechanical limited-slip differential anymore? I've heard rumors and read on MotoringFile.com that they've replaced it with an E-diff (basically braking the inside wheel), but I'm hoping those reports are wrong. I asked the dealer a few weeks ago when I test drove a car, and he hadn't heard anything about that, but he didn't seem all that well informed.

 

Nope, the LSD is gone, apparently for good...

There are aftermarket alternatives for the R53, not sure about the R56 but I don't see any reason why an aftermarket LSD wouldn't work there.

 

Damn. I think that's a deal breaker. I hope I can still order an '09.

 

Since the electronic version is supposed to be more effective, and lighter weight, why is that a deal breaker? Did you read the article in MotoringFile where they we able to do some testing?

 

If it's an everyday driver, the ediff is just fine.

Track car will be better off with a mechanical LSD--it depends on what you're using it for.

 

Has anybody heard absolutely for sure that the LSD will not be available for the 2010 models? My salesperson has not heard anything about it yet and was able to order it on the 2010 that we ordered on August 8. Won't be a deal breaker but would really prefer the mechanical.

 

What's the big deal, you'll never even know the difference. At least I wouldn't...

 

How can it be lighter? I believe LSD vs open diff weight difference is miserable.

 

It's a deal breaker because the main reason I'm getting this car is to autocross, and I don't want to have to prematurely replace brake pads and rotors in addition to the legendary premature replacement of front tires with the MCS. Also, greatly increasing the use of the brakes by using them to control inside wheel spin in turns in addition to the already heavy use in an autocross will lead to fade earlier, which will mean slower times. Also, I'm sceptical about how much lighter the e-diff will be compared to the diff they already have to put on the car. Why is the open diff any lighter? BTW, read th MotoringFile article and it sounded like it borrowed liberally from a BMW press release. I the e-diff is so great, why does BMW reserve the mechanical diff for the M cars?

 

Whoops!

 

From what I've heard about the BMW e-diff from 135 and 335 owners, it works pretty well, but after 3 autoX runs, the brakes are fried. Your pocketbook would know the difference.

 

Accel, the ediff is lighter. It's just electronics, adds essentially no weight. The LSD is a mechanical piece of hardware, it does add weight, it's the one single disadvantage of it. The ediff is great for an everyday car, in that application it makes more sense than a mechanical LSD. On the track, things are different...

Definitely worth it for the track for the above mentioned reasons. I've had the same experience as Koitus with 135i drivers, one of whom has put a mechanical LSD on the car (he's a fantastic driver btw, one of the best I know).

 

I thought the e-diff was a little more effective than the LSD on the track personally, but I still like the feel of the mechanical unit despite the e-diff having more lock and feeling a lot more seamless when cornering. Although the difference in smoothness is more noticeable on the street when the LSD can seem pretty assertive. Anyways, just my opinion.

I'd also be concerned with the extra wear it causes, especially on the track with stock brakes. I think the weight penalty is pretty much negligible.

 

The main thing is the wear. I personally don't like the way it feels on the track, but that's probably because I'm so used to the mechanical LSD.

I've seen 135i's just smoke brake pads on the track.....

 

If you are using the brakes that heavily, is it wise to use OEM pads? There have been reports here of people melting them on track runs.

 

I've autocrossed my 2009 JCW with E-diff and it did just fine. Had an '06 S before that with mech LSD and my butt dyno couldn't really describe to you any difference. With stock brakepads, I don't see increased wear as being that much of a problem. You'll go through tires much faster depending on how often you 'cross.

 

No, you shouldn't use stock pads. The guy I mentioned earlier roasted track pads. If you really want to see a pad melt, watch someone put their ebrake on after a session; the pads can weld to the rotor. Seen that happen once (not to me--that's about the only dumb thing I haven't done at the track yet), and it wasnt' pretty......

Ediff may be fine on autocross; they're relatively short runs. Extended time on the track and the ediff isn't a rotr/pad friendly combo though.

 

So, what people with JCWs do? They all come with the ediff.

 

They fry their brake pads.

The ediff supposedly helps more with torque steer. For day to day driving, like I said, it's just fine. And most JCW's don't see the track.

Torque steer can also be significantly improved with a tuned suspension, which is a better solution for the track, but more expensive. The ediff is significantly cheaper, it's fine for every day, but it's not the best setup for the track. That's not to say it can't be run on the track and be effective, but it's not a rotor or brake pad friendly setup. I suspect that may be part of the reason for the new JCW ducts...

 

Have you confirmed this with a dealer? A person on another thread ordered it and indicated that the system took the order and that they hadn't notified him that it had been removed from his build. There was speculation that they might still be available until they run out at some point during the 2010 model year.

-Adam

 

I wish. Right after I posted the first message, I called the guy who I was going to order my MCS from and he confirmed that you can't order a 2010 with the mechanical LSD.

 

I think that just killed the deal for us. I really wanted a car with a factory LSD. I think I would fry the pads using the ediff on a single RallyX run.

 

It may be comparing Fuji's to Granny Smith's, but take note that the BMW M3 uses an e-diff as well, and people don't often complain about that car. It's gotten generally positive reviews in its effectiveness. But if your mind is made, then your mind is made.

 

As has been noted here, the e-diff is not a problem for normal street use. If you ever got the brakes hot enough for it to be a problem on the street, you'd have to worry about felony reckless driving charges, and being chased by an entire police department, like Need for Speed: Most Wanted.

What conechaser and I are talking about is use in competition. I haven't seen many 335s autocrossed seriously, but the 135 is a pretty strong contender in DS, and I've heard from almost everyone I know who's driven one that the brakes take a beating, and by the third run, start to fade. Again, if the e-diff was as great as it's being touted by BMW, why do they put a mechanical LSD on the M cars? It's all marketing to cover up the fact that they want to cust costs in a way that most consumers wouldn't notice.

 

guess i got one of the last mech LSDs in my 2009. Wonder if it brings my value up.