[larryn]

My E90 330 is a handful to drive with sticky tires on it on the autox course, as far as getting the power down goes. I can easily spin my 275 race rubber coming out of corners, if I don't carefully feather the trottle.

The 335 is going to may that even more apprarent. If they off a 335Si with LSD, I'll get that, otherwise, it's a waste of power for what I use it for. Just seeing these few videos, you can see that it's very easy to smoke the inside tire. That's not going to help anybody here, unless they only care about 1/4 mile times.

[vleivo]

New bmws not having LSD is probably the biggest negative thing about them, ultimate driving machine spinning one wheel, is just wrong.

[mkoesel]

True but for 99% of BMW drivers they will never notice the difference.

Plus you can get one $1500. That's like half the price of useless 20" rims or tacky body kit (not that all body kits are tacky).

[DLJJ3399]

Originally Posted by visor

Did you go through that link I provided at howstuffworks.com?

Trust us, when you have 300 lb-ft going thru only one axle, an open differential with electronic slip control is a poor substitute for an LSD that is the only way to put all that power down to the ground effectively.

Drive your car hard (safely of course, with no traffic around you please) thru some turns with DSC on and then with DSC partially off, then you'll appreciate that even our measly 255hp/220lbft 330i's can do with an LSD. If you don't appreciate it, that means you're not driving it hard enough, and that's fine too. Not everyone enjoys taking a turn at 8-9/10ths.

But for the 335i with 300hp/300lbft to not have an LSD is kinda sad. I can't imagine driving it with DSC even partially off. But you can already see the results of that in those 2 video reviews that have been posted elsewhere on this forum. Anytime the driver powers out of a corner you only see one tire mark on the ground (the wheel on the inside corner) and the driver has to counter-steer madly to catch the tail as that tire slips too much.

I saw it. Thanks for the 411.

[abc]

so... LSD is only helpful in some kind of turn that is aggressive and you're gassing it, whether turning into or turning out of.... emergency avoidance or recreational.... that right?

[JO3]

LSD helps when you are gassing it hard enough to break traction. Regardless if you are turning or not. (it's just a lot easier to lose traction while in a turn) Just like AWD

[ropedog]

If that statment is correct (i think i read that somewhere)...
Please someone explain to me why BMW would not put a limited slip diff. in a turbo 300hp $50K car. It seems terrible to me, and it might make me look elsewhere (G35 coupe) when I get to the point of buying one.
Any thoughts/comments... Please help.

[Brett]

LSD is reserved for M3. Old news.

[bmwhomosapien]

what's lsd

[epiphone3]

Originally Posted by visor

Just wondering what others think of the lack of a limited slip diff in the 335i.

Especially with 300 hp and 300 lb-ft, how are the rear wheels (which are exactly the same sizes/widths as 330i's SP) supposed to have traction with just only an open diff modulated by brakes (DSC/DTC).

I can't imagine trying to turn off DSC/DTC on this monster!
With max torque starting at a low 1300 rpm, that would be downright dangerous!

Even the IS350 has the option of LSD with the sports package.
Why, oh, why did BMW not include even the option of an LSD?

I know, I know, some of you will say BMW saves the LSD for the M variants, but at least give us an option for the Ultimate Driving Machine!

E90's have an electric differential lock. This combined with DSC/DTC controls make it zero concern to have high torque 335i.

IT IS NOT AN OPEN DIFF> If you leave the car in DTC mode, the electronic locking function should still work and you should be able to get limited burn out of both tires is what I am saying. Those guys who have troubles controlling the 330i... after watching the video seen earlier in this thread, I think your driving needs help more than the car.

[visor]

Originally Posted by epiphone3

E90's have an electric differential lock. This combined with DSC/DTC controls make it zero concern to have high torque 335i.

IT IS NOT AN OPEN DIFF> If you leave the car in DTC mode, the electronic locking function should still work and you should be able to get limited burn out of both tires is what I am saying. Those guys who have troubles controlling the 330i... after watching the video seen earlier in this thread, I think your driving needs help more than the car.

I don't what is your definition of an "electric differential lock", but I do know the E90/92/46 (except for M variants) all have open differentials that use DSC braking to control slip.

If you don't know how diffs work, please check out:
http://auto.howstuffworks.com/differential.htm

[ksfrogman]

Originally Posted by epiphone3

E90's have an electric differential lock. This combined with DSC/DTC controls make it zero concern to have high torque 335i.

IT IS NOT AN OPEN DIFF> If you leave the car in DTC mode, the electronic locking function should still work and you should be able to get limited burn out of both tires is what I am saying. Those guys who have troubles controlling the 330i... after watching the video seen earlier in this thread, I think your driving needs help more than the car.

So epiphone3, would you please visit this thread that I posted a few days ago...

http://e90post.com/forums/showthread...ht=mods+matter

and check out that E90 3-Series Performance Open Differential? I'm wondering if I would be losing this "electronic locking function" if I were to go this route.

Thank you.

[arcrox]

Originally Posted by bmwhomosapien

what's lsd

RTFT

[Brett]

Originally Posted by arcrox

RTFT

Whats RTFT? J/k

-Brett

[visor]

Originally Posted by bmwhomosapien

what's lsd

Give the guy some slack. He just posted on a related thread that was just appended to this one.

LSD=limited slip differential

Check out this site to differentiate between the different differentials :
http://auto.howstuffworks.com/differential.htm

[Moderato]

I think the bottom line is that 99% of E92 335i owners would never drive aggresively enough to need an LSD. DTC will most likely be adequate for those 99%. Me personally, I like having the real LSD. I noticed a huge difference in how the car felt when I went from my 04 330i (open diff) to the 05 M3 (LSD).

[epiphone3]

Originally Posted by visor

I don't what is your definition of an "electric differential lock", but I do know the E90/92/46 (except for M variants) all have open differentials that use DSC braking to control slip.

If you don't know how diffs work, please check out:
http://auto.howstuffworks.com/differential.htm

I do know how diffs work. I am a mechanical engineer and I made a LSD final drive system for my design project in University... thanks for the link though.

So the definition of EDL, by BMW, is:
Electronic Differential Lock (EDL).
The Electronic Differential Lock (EDL) applies brake force with the utmost precision to a rotating drive wheel up to a certain speed and then transfers the torque to the other wheel. An additional hydraulic pump is responsible for this transferral: if a pre-determined torque value for the wheels is exceeded, the pressure is rerouted via a magnetic valve to a faster-turning wheel, thereby braking it.

An open-diff works like this: if a wheel starts to slip (i.e. spin faster), the natural tendancy for the open-diff is to send more power to this wheel.

Moving forward, the EDL will slow that faster spinning wheel thus causing the open-diff to send more power to the wheel with grip.

An LSD will allow on wheel to slip a certain amount before transferring, typically up to 25% of the engine's torque, to the wheel with grip.

There is also the 100% M-differential found in the current M3. The M-differenatial is not a conventional LSD as it is essentially a clutch pack that can transfer power side-to-side. This one is so flexible that it can transfer up to 100% of the engine's torque to one wheel, unlike the typical LSD that can only transfer approx. 25%.

To me, the LSD that BMW would possibly put in the 335i, that is, a 25% LSD is basically six in one and a half dozen in the other when compared to the open-diff with EDL.

This is what I was trying to get at. While the open diff is technically open, all it does, really, is use a different method to transfer power than the complicated gear systems found in 25% LSDs. It seems simpler and, for the most part, as effective as a 25% LSD and cheaper (i.e. keep car cost down to allow lower price).

Correct me if I am wrong.

[ksfrogman]

Originally Posted by epiphone3

I do know how diffs work. I am a mechanical engineer and I made a LSD final drive system for my design project in University... thanks for the link though.

So the definition of EDL, by BMW, is:
Electronic Differential Lock (EDL).
The Electronic Differential Lock (EDL) applies brake force with the utmost precision to a rotating drive wheel up to a certain speed and then transfers the torque to the other wheel. An additional hydraulic pump is responsible for this transferral: if a pre-determined torque value for the wheels is exceeded, the pressure is rerouted via a magnetic valve to a faster-turning wheel, thereby braking it.

An open-diff works like this: if a wheel starts to slip (i.e. spin faster), the natural tendancy for the open-diff is to send more power to this wheel.

Moving forward, the EDL will slow that faster spinning wheel thus causing the open-diff to send more power to the wheel with grip.

An LSD will allow on wheel to slip a certain amount before transferring, typically up to 25% of the engine's torque, to the wheel with grip.

There is also the 100% M-differential found in the current M3. The M-differenatial is not a conventional LSD as it is essentially a clutch pack that can transfer power side-to-side. This one is so flexible that it can transfer up to 100% of the engine's torque to one wheel, unlike the typical LSD that can only transfer approx. 25%.

To me, the LSD that BMW would possibly put in the 335i, that is, a 25% LSD is basically six in one and a half dozen in the other when compared to the open-diff with EDL.

This is what I was trying to get at. While the open diff is technically open, all it does, really, is use a different method to transfer power than the complicated gear systems found in 25% LSDs. It seems simpler and, for the most part, as effective as a 25% LSD and cheaper (i.e. keep car cost down to allow lower price).

Correct me if I am wrong.

So once again, if you scroll up a few posts to my last thread, the main question I have is would it be disadvantageous to switch out the stock diff to a performance open diff? I am interested in having the lower gearing.

[epiphone3]

Originally Posted by ksfrogman

So once again, if you scroll up a few posts to my last thread, the main question I have is would it be disadvantageous to switch out the stock diff to a performance open diff? I am interested in having the lower gearing.

I wouldn't think that switching out the stock open diff for another open diff would be disadvantageous. The way I understand it is that the EDL system is external to the differential itself.

I guess the only way to know for sure though is to lift the car and see what electronics are hooked up to the diff. My guess is that you can just swap the diff though

[ksfrogman]

Originally Posted by epiphone3

I wouldn't think that switching out the stock open diff for another open diff would be disadvantageous. The way I understand it is that the EDL system is external to the differential itself.

I guess the only way to know for sure though is to lift the car and see what electronics are hooked up to the diff. My guess is that you can just swap the diff though

awesome. thanks!

[mkoesel]

Originally Posted by ksfrogman

awesome. thanks!

Question, are you swapping to the OEM 3.64 rear end (the one that the auto uses)?

[ksfrogman]

Originally Posted by mkoesel

Question, are you swapping to the OEM 3.64 rear end (the one that the auto uses)?

That's a question that evokes a question. I didn't realize that this was the steptronic E90's diff, is it?

The upgraded performance open diff sold on Bimmerworld is a 3.64 for the 330i; stock ratio 3.15. For the 325i, they offer a 3.73 (instead of the OEM 3.23).

http://e90post.com/forums/showthread...ht=mods+matter