[Bubbles]

Comments? 335i to get 135i’s E-Diff in Future Variant

Sections: E81/82/E88 1 Series, E90 3 Series Mar 12th, 2008



BimmerFile Exclusive: According to some very well placed sources, electronic differential and specialized DSC currently found in the 135i will eventually make it’s way to a special performance variant of the 335i expect in the next few years. Look for the 335i to follow along the tradition of the 330i Performance Package that was offered over the last several model years of the E46’s model life-cycle (US only) complete with many of the components found in the newly released “BMW Performance” catalogue.


Written By: Gabe


Link to Article

[O-cha]

Originally Posted by Bubbles

According to some very well placed sources

BMW themselves said so.


In order to satisfy that demand on the part of performance-oriented spirited drivers, as of
March 2008 the 135i will be fitted with the NEW DSC function program that simulates
the action of a mechanical differential lock. The system uses the typical BMW open type
differential and is comprised solely of an electronic intervention program inside the DSC.

When the vehicle is in tight bend the DSC applies the brakes the spinning (inside) driving
wheel, the torque is then transmitted to the outside wheel which is carrying most of the
load, optimizing power and maintaining vehicle speed trough the corner. The new function
implemented in the DSC control module is thus, in effect, DTC without modulation
of engine output. The DSC and DTC functions are unaffected by it.

In comparison with a mechanical differential lock, the advantage of the new DSC program
function is more than just the fact that it is substantially more cost effective. Whereas a
mechanical differential lock is permanently active, this DSC Function only comes into
action only when required and if the DSC/DTC is switched off. Nor does it add to the
vehicle weight and fuel consumption.

Furthermore, the function does not affect handling stability in DSC or DTC mode and the
familiar understeer tendency produced by mechanical differential locks is also avoided.
The feature will also be introduced on BMW 3 Series models with higher performance
engines at a later date.

[down4it]

Originally Posted by O-cha

BMW themselves said so.


In order to satisfy that demand on the part of performance-oriented spirited drivers, as of
March 2008 the 135i will be fitted with the NEW DSC function program that simulates
the action of a mechanical differential lock. The system uses the typical BMW open type
differential and is comprised solely of an electronic intervention program inside the DSC.

When the vehicle is in tight bend the DSC applies the brakes the spinning (inside) driving
wheel, the torque is then transmitted to the outside wheel which is carrying most of the
load, optimizing power and maintaining vehicle speed trough the corner. The new function
implemented in the DSC control module is thus, in effect, DTC without modulation
of engine output. The DSC and DTC functions are unaffected by it.

In comparison with a mechanical differential lock, the advantage of the new DSC program
function is more than just the fact that it is substantially more cost effective. Whereas a
mechanical differential lock is permanently active, this DSC Function only comes into
action only when required and if the DSC/DTC is switched off. Nor does it add to the
vehicle weight and fuel consumption.

Furthermore, the function does not affect handling stability in DSC or DTC mode and the
familiar understeer tendency produced by mechanical differential locks is also avoided.
The feature will also be introduced on BMW 3 Series models with higher performance
engines at a later date.

But we already have this DSC function on the 335... It applies the brakes when your tires are spinning if you press the button one time it turns off dtc but you still have dsc on.. If you press it for 5 seconds are traction functions are turned off...

[O-cha]

Originally Posted by down4it

But we already have this DSC function on the 335... It applies the brakes when your tires are spinning if you press the button one time it turns off dtc but you still have dsc on.. If you press it for 5 seconds are traction functions are turned off...

If you press it once it turns DSC of and DTC on, hold it and it turns both off. But I got what you meant.

The 135 when both DSC and DTC are off it still brakes the spinning wheel where as the 335 it will just spin. Nice but it's not a replacement for a true LSD.

It's DTC without the possibility of engine intervention. But if you have DTC on and you got fuel cut then you shouldn't have been doing what you were doing anyway.

[DanMardik]

Originally Posted by down4it

But we already have this DSC function on the 335... It applies the brakes when your tires are spinning if you press the button one time it turns off dtc but you still have dsc on.. If you press it for 5 seconds are traction functions are turned off...

Right, but I think this new "E" feature helps modulate more evenly the dispersion of power throughout the rear wheel drive train..

unless I'm wrong.

[DanMardik]

Also, if this is purely a software upgrade to the DSC, doesn't it mean that we could potentially add it to our 335's without actually having to change any real components?

[5soko]

same crap, give us a damn mechanical LSD....

[astris]

Is it just me or does that seem more complicated and less effective than an LSD?

[raceyBMW]

Magazine reviews FWIW of the 135 have given the E-Diff system pretty good marks in terms of its ability to mimic a true mechanical LSD. Honestly this would probably work for 99.9% of us, even in track situations.

[Dan335i]

Pushing the button once on the 335 turns off DTC.Holding it for 5 seconds shuts off the DTC and the DSC,not the other way around.

[O-cha]

Originally Posted by Dan335i

Pushing the button once on the 335 turns off DTC.Holding it for 5 seconds shuts off the DTC and the DSC,not the other way around.

No it's exactly as I said. Standard when you start your car is DSC on which is the most often intervening one. Hit the button once and you turn DSC off and turn DTC on which allows for more wheels spin and rotation before it intervenes. Hold it and you turn both off.

You can go look over the literature yourself if you would like.

[rambino]

The E Diff is Junk..

Its just an electronic biased braking system that transfers the power super quickly back and forth between the 2 wheels, just like the Benzs have..

Its Fake, and it Sucks.. I for one would remove that electronic crap and put a real diff in.. my 2cents

[judec]

the e-diff is cool. it will help U to change your rear brake pads more often, U never get bored of them LOL.

But no - I agree this work-around (yes, I mean it, it's not a solution of the missing LSD issue, just a patch) will be sufficient for the majority of users. I heard it works. It's not more complicated like an LSD, especially not more like the M3 LSD - it's just a stupid algorithm in the existing SW using existing HW, what could be easier?

I also agree that cant fully substitute an LSD, only mimic some of its behaviour. What scares me a lot is if the e-diff will be standard, not an option, it will possibly make the installation of a true LSD more difficult - the damn code will want to brake the inner wheel even if it will be supposed to be made by LSD...

[O-cha]

Originally Posted by MarkNg335i

So which one is better to drive with, dsc or dtc on.

I drive with DTC on (one push). The engine intervention will never kick in if you're driving a proper line and not gassing it too much and otherwise just does the braking like the E-diff. If DTC cuts power you were most likely going to oversteer or understeer a good deal.

[stressdoc]

It's not an M-differential. Not even close.

But yes, the report of "higher performance engines" was interesting.

[leftcoastman]

With everything off (DSC button for 5+ seconds), it's spin city. Any attempt at launching out of corners will likely lead to bouncing off the rev limiter. At one track event last summer, a guy who was following me the whole time (couldn't get close enough to necessitate a point-by) told me that I was spewing smoke at every corner.

With the button pressed once, I will blow through a set of rear pads within two track days. The braking action is too prevalent.

Now, with a true LSD, I am in heaven and should have done this a long time ago. I can launch out of corners with little drama.

S4to335 is right. Nothing more frustrating than leading into a corner and watching people slingshot out while you feather the throttle to keep from roasting your tires.

[Dan335i]

Originally Posted by O-cha

No it's exactly as I said. Standard when you start your car is DSC on which is the most often intervening one. Hit the button once and you turn DSC off and turn DTC on which allows for more wheels spin and rotation before it intervenes. Hold it and you turn both off.

You can go look over the literature yourself if you would like.

Not looking for a heated discussion here.When you start your car naturally DTC and DSC are both active.Hitting the button once shuts off your DTC leaving only the DSC active.Holding the button for 5 seconds disables the DSC along with the DTC. Thats how it works on my car,and i,m sure on every other 335 also.

[O-cha]

Originally Posted by Dan335i

Not looking for a heated discussion here.When you start your car naturally DTC and DSC are both active.Hitting the button once shuts off your DTC leaving only the DSC active.Holding the button for 5 seconds disables the DSC along with the DTC. Thats how it works on my car,and i,m sure on every other 335 also.

You are wrong, please go read the BMW literature or drive your car. DSC is the stronger stability control, DTC is the weaker. If you really think hitting the button once turned on your stronger stability control then your just a special guy.

[BMWPower06]

sounds stupid, basically its DSC but instead of applying the brakes AND cutting engine power when a wheel slips, it just applies the brakes to the slipping wheel. Just put a damn LSD in it, a REAL one, none of this "E" crap

[morten_m]

Quaife ATB FTW!

[stefano7171]

Guys, the e-diff (braking the spinning wheel with all controls off and simulating the functions of a real mechanical LSD) is standard on all 335ì (e90, 91, 92 ans 93) manufactured since March 2007, as I have already pointed out in the past on the forum.
At least an all Euro-specs cars!
For example my one, built April 2007, has it and it works quite well.

[Orient330iNYC]

Originally Posted by Dan335i

Not looking for a heated discussion here.When you start your car naturally DTC and DSC are both active.Hitting the button once shuts off your DTC leaving only the DSC active.Holding the button for 5 seconds disables the DSC along with the DTC. Thats how it works on my car,and i,m sure on every other 335 also.

O-cha is right.

DSC is the default program. it has a much lower threshold of engagement, and will cut engine power, then apply brakes to reign in a spinning wheel and to bring the car back on course.

DTC is a modified DSC. higher threshold of engagement, uses primarily brakes rather than engine power cuts.

its one or the other on at any one time. they're just different software profiles for the same traction control/stability system.

the differences are in the manual. the DTC indicator in the cluster is an indicator that the DTC program is ON not off.