[stokedxiv]

I have a 330i, Automatic, Premium package, and I just got past the break in period. The other night it was raining so I turned off the traction control and stability management and was sliding the car around a bit in an empty lot. I noticed however that it seemed like the car has an open differential? I would assume that it would have some kind of limited slip, but that doesn't seem to be the case. Seemed like unless I really flicked the car sideways I would just get spinning of the inside rear wheel... which leads me to believe that the diff is open.

Anyway, what type of diff do I have in my car? And is there anyone who makes a nice 1.5way I could buy? Does the e90 sports package include a different differential?

Thanks guys
Charlie

[Xens]

Originally Posted by stokedxiv

I have a 330i, Automatic, Premium package, and I just got past the break in period. The other night it was raining so I turned off the traction control and stability management and was sliding the car around a bit in an empty lot. I noticed however that it seemed like the car has an open differential? I would assume that it would have some kind of limited slip, but that doesn't seem to be the case. Seemed like unless I really flicked the car sideways I would just get spinning of the inside rear wheel... which leads me to believe that the diff is open.

Anyway, what type of diff do I have in my car? And is there anyone who makes a nice 1.5way I could buy? Does the e90 sports package include a different differential?

Thanks guys
Charlie

Nope, no OEM LSD for E90 whatsoever and that's that. Don't know about aftermarket.

[Tierfreund]

The only BMW´s that come with a LSD from the factory these days are the M-cars. (M3, M5, M6, Z4M etc.)

[Sho]

We do have an open diff on our E90's.

[stokedxiv]

Damn, you'd think that for $40K+ you'd get an LSD

I'll have to look for some options

[Tierfreund]

Originally Posted by stokedxiv

Damn, you'd think that for $40K+ you'd get an LSD

Why?

Most people who spend 40k on a luxury sedan don´t go around burning rubber. So a LSD would be wasted on them. Actually the car´s handling is more benign without it, the fuel consuption is (very slightly) less, it is cheaper and lighter without it and so on.

There are only 2 reasons to have a LSD on a car:

1. Serious performance driving
- For someone into such BMW offers the M car(s).

2. Traction on slippery surfaces
- For traction on slippery surfaces the E90 will simulate (at low speeds) a LSD by braking a slipping wheel thus transfering power to the wheel with traction if you turn the DSC into DTC mode. It´s not as good as a LSD, but it´ll get you moving. And it´s just a line of software in the DSC instead of heavy machinery. That´s why nowadays even off-road vehicles (except for the hardcore versions) mostly don´t have LSDs anymore but software with brake appliance instead.

Driving a non-M BMW with such verve that you would miss a LSD puts you into a very small niche, so it´s understandable that BMW would not cater to you. That´s what the aftermarket is there for.

Besides, didn´t you say you drive an auto? That puts you even more in a niche. Trying to drift an auto...

[stokedxiv]

I understand what you're saying, and I agree that most people will never know the difference if their car has no LSD. However I think there should at least be the option of one, maybe we'll get that once the M version is released and we can swap some parts.

And yea yea, I know trying to drift an auto The E90 is just my daily driver, if I want to do some serious driving I pull out my FD RX-7, it's got an LSD along with some other toys

[wannabmw]

Originally Posted by Tierfreund

2. Traction on slippery surfaces
- For traction on slippery surfaces the E90 will simulate (at low speeds) a LSD by braking a slipping wheel thus transfering power to the wheel with traction if you turn the DSC into DTC mode. It´s not as good as a LSD, but it´ll get you moving. And it´s just a line of software in the DSC instead of heavy machinery.

I have several questions about the DSC system on a vehicle with xDrive:

1. It appears xDrive transfers power front/rear, not left/right other than by applying brakes (as you wrote). What happens when one front tire looses traction, won't the car pull if the brake is applied to the slipping wheel? This seems like a good time to open the xDrive clutch and stop sending power to the front. What if the driver wants to brake at the same time a front wheel is spinning? What if the driver downshifts and induces one of the front wheels to slip? When a rear tire spins, without LSD the power should transfer to the front wheels, right? What does the DSC do when both wheels on the same side spin?

2. How does an xDrive car handle when the DTC is turned off?

3. Under what conditions does the engine power get cut?

4. You mentioned DTC modes, I only know of on and off, are there are other selectable modes?

5. Can I switch to staggered tires (larger tires in the rear) without confusing the DSC and ABS? What effect does staggered tires have on xDrive power split to the front wheels?

[Mono]

Lexus IS does not have an LSD either. Not even in their sport package.

G35 offers one with the sport package for sedan and coupe regardless of transmission choice.

I think the sport package on the E90 should come with one. The people who opt for this package are the buyers that want more performance from the their E90. That's why they are willing to pay more for it.

[CSBM5]

Originally Posted by Mono

I think the sport package on the E90 should come with one. The people who opt for this package are the buyers that want more performance from the their E90. That's why they are willing to pay more for it.

It is insane for BMW not to offer a limited slip diff as an option any longer and only provide one on M-cars. On my 1985 535i it was a $395 option, and I think it was close to that price on my 1988 735i. At least you could order a car with one in the old days. Now you have to fork out $2500 or more in the aftermarket once you get the car. BMW could probably make a decent profit adding an LSD as an option for $995. Oh well...it was one of the factors that added to the value of the M5 to me compared to the 540i.

[3m52]

http://www.diffsonline.com/product/customdiff2.htm

[Coyot]

I' m told by local BMW people in Greece that typical mechanical LSDs will not cooperate either smoothly or efficiently with the car's DTC/DSC (which already functions as "passive LSD"), and may cause excessive brake wear or even get damaged themselves on the long run.

BMW "M" differentials on the other hand, which do have a variable torque bias, are electronically controlled by the M cars' respective Engine Control Units, so they are not an option for ordinary E90/92s.

It seems (please, correct me if I am wrong) that only torque-sensitive LSDs such as the "Automatic Torque Biasing" ones produced by QUAIFE can work successfully in cars with BMW's newest DTC/DSC.
However, an ATB for E90/92 is not offered "off-the-shelf" by Quaife right now. They need a group order of at least 10-12 pieces for whatever they haven't already produced.

I'm an absolute newbie and not familiar with the forum's policies in similar matters, but I suggest it might be a good idea to seek information from Quaife, as a Forum. I guess we could get a more substantial response from them than as individuals.