If BMW doesnt put LSD (limit slip diff) in 135i, would aftermarket LSD void warranty?

335i=:) · 08-23-2007, 06:18 PM

Quote:

Originally Posted by larryn

Actually, it's not transferring torque, it's just maintaining torque, as apposed to ASC reatarding it.

+1 , there is no transfer. The torque n the wheel that's not slipping stays the same and the slipping wheel maintain's torque better then without.

In my 335i it's very easy to tell when this is happening. Although if you push it really hard with the DTC button pushed once. It will still cut the throttle or gas to the engine. And with procede, I'm still more likely to understeer with the stock setup. The back end only comes out on corner exit under WOT. And it's not much.

Advevo · 08-23-2007, 06:24 PM

if you have 40% lock lsd what will happen with edl then.

Drexler have variable locking diff 10 to 90 procent. how does edl react to that.

Than an other problem occurs. Bmw has wealded the final drives on its open diff. So you can not bolt on youre final drive on youre LSD.

It s just a pity bmw works this way. There is no room for enthusiasts anymore. Maybe it s getting time to go to an other brand.

mikeo · 08-23-2007, 06:32 PM

Guys, on a true open differential once one wheel spins ALL the torque goes to that spinning wheel, with effectively no drive force being transmitted to the other wheel. It follows that if the EDL applies the brake to the spinning wheel, a significant percentage of the torque MUST be sent to the non-spinning wheel.

gotgemini2000 · 08-23-2007, 10:07 PM

I understand the concept of braking the wheel that spins to transmit power to the wheel with traction, but BMW's system still seems so backwards. My toyota pickup has a locking differential setup and my fathers 1992 E36 BMW 325i had a LSD, why does BMW have mess this simple system up? I know it sounds juvenile but why can't I lay down 2 strips of rubber pulling off the line with my brand new 35,000 dollar car? Why can't I take a 135i and fly through corners knowing that both wheels are transmitting full power to the ground? It's supposed to be the "Ultimate Driving Machine."

Powerman · 08-23-2007, 10:20 PM

I'm confused. There seems to be discrepencys here. Maybe I'm wrong. I'm no expert, but...

In an open diff, power will seek the path of least resistance. If one wheel looses grip, all power will go to that wheel just like mikeo says. If the brake is applied to slow, or stop the spin, an equal amount of power will be sent to the other wheel. What I want to know is what is the limit? Say 100% of power is lost to spinning wheel, as much as 50% braking force is applied, transfering 50% to the other side. You still only have 50% power to the wheel with grip, and none to the other side because the brake is keeping it from spinning???

A good mechanical slip has variable bias. More than 70% and it starts to behave as a locked diff, or a spool so to speak. The friction plates will hold the other wheel at the bias set. So say 60% ratio will always send 60% to the other wheel with more grip until the limit is met on the clutches. The diff will slip, but the friction will still send the power to the wheel with more grip seamlessly and the other wheel will still be driven instead of braked. I see no reason that the ELD will not still work with such a set up. Except of course if it engages before the mechanical slip. But I don't see how that would happen, because even if the wheel does slip, the power is still being transfered before hand.

I also don't see the problem with warranty either. BMW will not warranty the LSD, the manufacturer will for probably 1 years or so. A locking differential, or spool has the ability to send 100% of the power to the wheel with the most grip. Stick big sticky tires on and the half shaft might snap before the tires loose grip. If you had a very high biased LSD, say 70% or more, you MIGHT be able to excede torque ratings for the half shafts. I don't see that happening with moderate LSDs and close to stock sized rubber. The only way I do see that happening is if you have a very tight LSD and had enough power to smoke the tires and got wheel hop out of it. Wheel hop has been the demise of many a shaft. Again, I don't see that being a huge worry with a chipped and slipped 135i.

The other thing is the drive line up to the diff is capable of delivering 100% power including safety margin. A very tight LSD might exceed the limit of the driven half shaft, but it isn't going to multiply torque through the drive line. I don't see how you will cause driveline damage from a moderate LSD. If you had crazy power,and sticky rubber, and you dumped the clutch, you could blow a joint or worse, but you would be stupid and deserve what you get. I don't see how that would be an issue with 99% of the 135i drivers.

Quaiff already has a Torsen LSD for the 335i. $1500 One tuner and others are using it. Turner already has a clutch LSD for the 335i. Quite expensive at this point. More than $2000. IIRC $3600 installed in a new diff, and then you get $900 back for core charge. hopefully that will come down. I have no idea about the diffs being welded, but can't see how that would stop putting in a LSD. I have not heard of that, nor do I know anything about BMW diffs. I also don't see a problem with cruise control. Many diffs have speed rings on the diff and it is always accounted for in aftermarket setups.

Please correct me on any of this stuff. I'm quite interested.

gotgemini2000 · 08-23-2007, 10:48 PM

Powerman, you sound more knowledgeable than me, however, my understanding of the 135i's "E-LSD" is this:
As you are exiting a corner, at the point where you would want to apply maximum power to the road, a car with a LSD senses which wheel has the most power and applies this power to that wheel. With centrifugal force forcing the car out away from the curve, the inner wheel typically has less traction and thus a LSD applies more power to the outer wheel. The 135i on the other hand, with it's "E-LSD", applies its power differently. Instead of simply varying the amount of power applied to each wheel, it brakes the inner wheel in order to apply more power to the outer wheel. I'm not sure whether this results in power loss as far as how much power is applied to the ground, but, the fact remains, that if a wheel which is sitting on the ground is being "braked" then the car must not be exiting the corner as efficiently as it would if more power were simply being applied to the outer wheel. On the plus side, given that the "E-LSD" would typically brake the inner wheel, it could perhaps result in an even tighter turning radius. By this I mean that because one wheel is braked the car could potentially pivot around the rear inner wheel much like a tractor with right and left side brakes. (ok probably not, it would be cool though)

All this being said, I could easily be wrong. I'm a 19 year old Geology/Political Science major who grew up on a farm so the workings of the "E-LSD" on the 135i are hardly my specialty.

gemini330zhp · 08-24-2007, 12:52 AM

Ok Fellas I think BMW did alot of Research and Development into this E-LSD thingy. It will probally work very well so dont sweat it. Lets wait for the reviews when the car comes out Im sure we will get our answers. So for the time being I am just going to enjoy my 06 M3 with M LSD DIFF!!!!

imported_Torque · 08-24-2007, 02:07 AM

Hi. I'm from Italy. Actually I have a 120d but i would buy a 123d coupe.
I think that a good EDL would replace a LSD, but it must be not too invasive. I have run in some track-day with my 120d that have over 200hp, and i have verified that if the actual electronic controls would be less invasive it would be functional. But in the actual state i have to deactivate it all because it cut too much power and so, often in exit of narrow bend the internal wheel slipped.

I don't understand something about the EDL. Will it be present only on 135i coupe or also in all 1er coupe? and will it be an optional or not?
I'd like to buy a 123d M sport, will it have this EDL??

Advevo · 08-24-2007, 02:54 AM

123d has EDL 120d not.

My understanding the EDL will not cut power only brakes the spinning wheel.

If you go to a track day bring a set a rear brake with you i quess youre rear pads will be gone very fast when driven hard. Or do a nice drift day on wet. Youre rear pads will be gone so damn fast.

On 335i after march 2007 production they wealded the final drive to the opendiff. So you need a new finaldrive if you can find one which you can bolt onto the diff.

imported_Torque · 08-24-2007, 03:28 AM

[quote=Advevo;14474]
123d has EDL 120d not.
[quote]
Oh thanks! but not as an optional? i don't find anything on the brochure!

Quote:

Originally Posted by Advevo

123d has EDL 120d not.
My understanding the EDL will not cut power only brakes the spinning wheel.

yeah! in fact I suppose it will be great! but it must be not too invasive, otherwise goodbye driving pleasure!

Quote:

Originally Posted by Advevo

123d has EDL 120d not.
If you go to a track day bring a set a rear brake with you i quess youre rear pads will be gone very fast when driven hard. Or do a nice drift day on wet. Youre rear pads will be gone so damn fast.

You're right, with the actual TC I already burn first the rear ones (sometimes I forget to deactivate it on the road...:biggrin

, with the EDL it will be worse, specially in track!

inTgr8r · 08-24-2007, 06:26 AM

Quote:

Originally Posted by gemini06m3

Ok Fellas I think BMW did alot of Research and Development into this E-LSD thingy. It will probally work very well so dont sweat it. Lets wait for the reviews when the car comes out Im sure we will get our answers. So for the time being I am just going to enjoy my 06 M3 with M LSD DIFF!!!!

I hope you're right!
Like you I'm used to having an M diff.

bradford · 08-24-2007, 09:09 AM

Quote:

Originally Posted by Advevo

If you go to a track day bring a set a rear brake with you i quess youre rear pads will be gone very fast when driven hard. Or do a nice drift day on wet. Youre rear pads will be gone so damn fast.

It's not that bad at all. I used to get nearly a whole track season out of the rear pads on my stage 3 A4, which used EDL as well. And with very stiff rear springs and a big rear ARB, EDL would kick in all the time upon corner exit.

TheoIam · 08-24-2007, 09:24 AM

Quote:

Originally Posted by inTgr8r

I hope you're right!
Like you I'm used to having an M diff.

Ditto times 2.

R32 · 08-24-2007, 09:27 AM

Quote:

Originally Posted by bradford

I used to get nearly a whole track season out of the rear pads on my stage 3 A4, which used EDL as well.

that might not be a totally analogous situation, since less than half of your engine's torque is going to the rears (please correct me if i'm wrong).

bradford · 08-24-2007, 09:43 AM

Well upon corner exit approximately 75% of the torque would be going to the rear due to the Torsen center diff (as the fronts scramble for traction) and my A4 was making about 320 at the crank.

Also, the rear brakes on the A4 were little tiny solid biscuits - nowhere near the heat dissipation capability of the huge vented rotors BMW puts on it's rears.

Not totally analogous, no, but a valid datapoint.

GoingTooFast · 08-24-2007, 09:47 AM

Quote:

Originally Posted by Advevo

123d has EDL 120d not.

My understanding the EDL will not cut power only brakes the spinning wheel.

Correct!

Quote:

Originally Posted by Advevo

If you go to a track day bring a set a rear brake with you i quess youre rear pads will be gone very fast when driven hard. Or do a nice drift day on wet. Youre rear pads will be gone so damn fast.

Wrong!

Quote:

Originally Posted by Advevo

On 335i after march 2007 production they wealded the final drive to the opendiff. So you need a new finaldrive if you can find one which you can bolt onto the diff.

Maybe this is because after March 2007 the 335i got the Dynamic Performance Control diff. (aka E-LSD)which is a mechatronic system where the final drive is combined with two superimposed gearsets and two electronically controlled multiple-plate brakes (one for each wheel):

So, it's NOT your rear pads that may wear-off but these multiple-plate brakes on the differential itself, just like the multiple clutch plates do in a normal LSD.

All the ABS system do is providing the sensors for detecting wheel spin.

The mechatronic system takes up to 100 milliseconds for generating the maximum breaking force. And, regardless of the drive power generated by the engine the maximum difference in forces between the left- and right-hand rear wheel which can be built up by the system is 1,800 Nm. This defines your percentage of locking.

This setup also means that at NO engine torque (with the clutch disengaged for instance) you still benefit from the locking effect as opposed to what would happened with a mechanical LSD where you were basically driving with an open diff.

atr_hugo · 08-24-2007, 10:07 AM

Wow - I've been looking for a picture of the diff. Great!!

(And BTW, nice car you currently have, since I have one too. ; -)

larryn · 08-24-2007, 10:09 AM

GoingTooFast, awesome info! I had not seen a diagram of the EDL diff before.

It looks like there's a new maintenance item in those braking plates then, but it clearly shows side of the diff unbolt for access to them, unlike any other diff I've ever seen.

It also looks like replacing the diff with a real locking differential would automaticallt defeat the new system, since you'd be removing it, by replacing the diff. I think that installing new locking internals in that diff (a la Quaife) would be difficult, at best.

I wonder if you'd have to source new half shafts that are longer.

R32 · 08-24-2007, 10:21 AM

Quote:

Originally Posted by bradford

Well upon corner exit approximately 75% of the torque would be going to the rear due to the Torsen center diff (as the fronts scramble for traction) and my A4 was making about 320 at the crank.

nice!!! i didn't realize that the torsen could transfer that much to the rear. i bet you raise a few eyebrows with that car.

GoingTooFast · 08-24-2007, 10:22 AM

I think it was already posted elsewhere...

BMW E-LSD

mikeo · 08-24-2007, 10:40 AM

So is this the dif that will be in the 135i?

Powerman · 08-24-2007, 10:43 AM

Is this really the electronic limited slip they are talking about in the 135i? The one that has been talked about in the 135 is electronic, not mechatronic. The one posted is another type of actual limited slip, not electronically simulated. Other manufacturers have been using independent brake circuits to brake the slipping wheel for a while. That is nothing new. While the brochure is ambiguous, I does not seem like the mechatronic LSD is what they are talking about.

08-23-2007, 06:24 PM	#46
Advevo Banned 581 Rep 1,170 Posts Drives: M2 Competition, E30 M3 DTM Join Date: Apr 2006 Location: Country where the taxes are too high!! iTrader: (0)	if you have 40% lock lsd what will happen with edl then. Drexler have variable locking diff 10 to 90 procent. how does edl react to that. Than an other problem occurs. Bmw has wealded the final drives on its open diff. So you can not bolt on youre final drive on youre LSD. It s just a pity bmw works this way. There is no room for enthusiasts anymore. Maybe it s getting time to go to an other brand.
	Appreciate 0 Quote

08-23-2007, 06:32 PM	#47
mikeo Santa Fe Concorso 103 Rep 2,984 Posts Drives: '11 M-sport 328i, '13 X1 28i Join Date: Jul 2007 Location: Santa Fe, NM iTrader: (3)	Guys, on a true open differential once one wheel spins ALL the torque goes to that spinning wheel, with effectively no drive force being transmitted to the other wheel. It follows that if the EDL applies the brake to the spinning wheel, a significant percentage of the torque MUST be sent to the non-spinning wheel. __________________ Santa Fe Concorso - The Southwest's Premier Automotive Gathering.
	Appreciate 0 Quote

08-23-2007, 10:07 PM	#48
gotgemini2000 Private First Class 23 Rep 158 Posts Drives: G80 & E46 M3, 6 speed manuals Join Date: Nov 2007 Location: PA iTrader: (0)	I understand the concept of braking the wheel that spins to transmit power to the wheel with traction, but BMW's system still seems so backwards. My toyota pickup has a locking differential setup and my fathers 1992 E36 BMW 325i had a LSD, why does BMW have mess this simple system up? I know it sounds juvenile but why can't I lay down 2 strips of rubber pulling off the line with my brand new 35,000 dollar car? Why can't I take a 135i and fly through corners knowing that both wheels are transmitting full power to the ground? It's supposed to be the "Ultimate Driving Machine."
	Appreciate 0 Quote

08-23-2007, 10:20 PM	#49
Powerman Private First Class 4 Rep 122 Posts Drives: Join Date: Jul 2007 iTrader: (0)	I'm confused. There seems to be discrepencys here. Maybe I'm wrong. I'm no expert, but... In an open diff, power will seek the path of least resistance. If one wheel looses grip, all power will go to that wheel just like mikeo says. If the brake is applied to slow, or stop the spin, an equal amount of power will be sent to the other wheel. What I want to know is what is the limit? Say 100% of power is lost to spinning wheel, as much as 50% braking force is applied, transfering 50% to the other side. You still only have 50% power to the wheel with grip, and none to the other side because the brake is keeping it from spinning??? A good mechanical slip has variable bias. More than 70% and it starts to behave as a locked diff, or a spool so to speak. The friction plates will hold the other wheel at the bias set. So say 60% ratio will always send 60% to the other wheel with more grip until the limit is met on the clutches. The diff will slip, but the friction will still send the power to the wheel with more grip seamlessly and the other wheel will still be driven instead of braked. I see no reason that the ELD will not still work with such a set up. Except of course if it engages before the mechanical slip. But I don't see how that would happen, because even if the wheel does slip, the power is still being transfered before hand. I also don't see the problem with warranty either. BMW will not warranty the LSD, the manufacturer will for probably 1 years or so. A locking differential, or spool has the ability to send 100% of the power to the wheel with the most grip. Stick big sticky tires on and the half shaft might snap before the tires loose grip. If you had a very high biased LSD, say 70% or more, you MIGHT be able to excede torque ratings for the half shafts. I don't see that happening with moderate LSDs and close to stock sized rubber. The only way I do see that happening is if you have a very tight LSD and had enough power to smoke the tires and got wheel hop out of it. Wheel hop has been the demise of many a shaft. Again, I don't see that being a huge worry with a chipped and slipped 135i. The other thing is the drive line up to the diff is capable of delivering 100% power including safety margin. A very tight LSD might exceed the limit of the driven half shaft, but it isn't going to multiply torque through the drive line. I don't see how you will cause driveline damage from a moderate LSD. If you had crazy power,and sticky rubber, and you dumped the clutch, you could blow a joint or worse, but you would be stupid and deserve what you get. I don't see how that would be an issue with 99% of the 135i drivers. Quaiff already has a Torsen LSD for the 335i. $1500 One tuner and others are using it. Turner already has a clutch LSD for the 335i. Quite expensive at this point. More than $2000. IIRC $3600 installed in a new diff, and then you get $900 back for core charge. hopefully that will come down. I have no idea about the diffs being welded, but can't see how that would stop putting in a LSD. I have not heard of that, nor do I know anything about BMW diffs. I also don't see a problem with cruise control. Many diffs have speed rings on the diff and it is always accounted for in aftermarket setups. Please correct me on any of this stuff. I'm quite interested.
	Appreciate 0 Quote

08-23-2007, 10:48 PM	#50
gotgemini2000 Private First Class 23 Rep 158 Posts Drives: G80 & E46 M3, 6 speed manuals Join Date: Nov 2007 Location: PA iTrader: (0)	Powerman, you sound more knowledgeable than me, however, my understanding of the 135i's "E-LSD" is this: As you are exiting a corner, at the point where you would want to apply maximum power to the road, a car with a LSD senses which wheel has the most power and applies this power to that wheel. With centrifugal force forcing the car out away from the curve, the inner wheel typically has less traction and thus a LSD applies more power to the outer wheel. The 135i on the other hand, with it's "E-LSD", applies its power differently. Instead of simply varying the amount of power applied to each wheel, it brakes the inner wheel in order to apply more power to the outer wheel. I'm not sure whether this results in power loss as far as how much power is applied to the ground, but, the fact remains, that if a wheel which is sitting on the ground is being "braked" then the car must not be exiting the corner as efficiently as it would if more power were simply being applied to the outer wheel. On the plus side, given that the "E-LSD" would typically brake the inner wheel, it could perhaps result in an even tighter turning radius. By this I mean that because one wheel is braked the car could potentially pivot around the rear inner wheel much like a tractor with right and left side brakes. (ok probably not, it would be cool though) All this being said, I could easily be wrong. I'm a 19 year old Geology/Political Science major who grew up on a farm so the workings of the "E-LSD" on the 135i are hardly my specialty.
	Appreciate 0 Quote

08-24-2007, 12:52 AM	#51
gemini330zhp Major 34 Rep 1,180 Posts Drives: 2008 M3 E90 Join Date: Jul 2005 Location: BergenCo NewJersey iTrader: (0)	Ok Fellas I think BMW did alot of Research and Development into this E-LSD thingy. It will probally work very well so dont sweat it. Lets wait for the reviews when the car comes out Im sure we will get our answers. So for the time being I am just going to enjoy my 06 M3 with M LSD DIFF!!!!
	Appreciate 0 Quote

08-24-2007, 02:07 AM	#52
imported_Torque New Member 0 Rep 6 Posts Drives: Join Date: Aug 2007 iTrader: (0)	Hi. I'm from Italy. Actually I have a 120d but i would buy a 123d coupe. I think that a good EDL would replace a LSD, but it must be not too invasive. I have run in some track-day with my 120d that have over 200hp, and i have verified that if the actual electronic controls would be less invasive it would be functional. But in the actual state i have to deactivate it all because it cut too much power and so, often in exit of narrow bend the internal wheel slipped. I don't understand something about the EDL. Will it be present only on 135i coupe or also in all 1er coupe? and will it be an optional or not? I'd like to buy a 123d M sport, will it have this EDL??
	Appreciate 0 Quote

08-24-2007, 02:54 AM	#53
Advevo Banned 581 Rep 1,170 Posts Drives: M2 Competition, E30 M3 DTM Join Date: Apr 2006 Location: Country where the taxes are too high!! iTrader: (0)	123d has EDL 120d not. My understanding the EDL will not cut power only brakes the spinning wheel. If you go to a track day bring a set a rear brake with you i quess youre rear pads will be gone very fast when driven hard. Or do a nice drift day on wet. Youre rear pads will be gone so damn fast. On 335i after march 2007 production they wealded the final drive to the opendiff. So you need a new finaldrive if you can find one which you can bolt onto the diff.
	Appreciate 0 Quote

08-24-2007, 09:43 AM	#59
bradford Major 28 Rep 1,035 Posts Drives: 2008 SGM 135i Join Date: Jul 2007 Location: Chicago > * iTrader: (4)	Well upon corner exit approximately 75% of the torque would be going to the rear due to the Torsen center diff (as the fronts scramble for traction) and my A4 was making about 320 at the crank. Also, the rear brakes on the A4 were little tiny solid biscuits - nowhere near the heat dissipation capability of the huge vented rotors BMW puts on it's rears. Not totally analogous, no, but a valid datapoint.
	Appreciate 0 Quote

08-24-2007, 10:07 AM	#61
atr_hugo No longer moderate 325 Rep 4,401 Posts Drives: '13 135i Join Date: Jun 2007 Location: - iTrader: (0)	Wow - I've been looking for a picture of the diff. Great!! (And BTW, nice car you currently have, since I have one too. ; -)
	Appreciate 0 Quote

08-24-2007, 10:09 AM	#62
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	GoingTooFast, awesome info! I had not seen a diagram of the EDL diff before. It looks like there's a new maintenance item in those braking plates then, but it clearly shows side of the diff unbolt for access to them, unlike any other diff I've ever seen. It also looks like replacing the diff with a real locking differential would automaticallt defeat the new system, since you'd be removing it, by replacing the diff. I think that installing new locking internals in that diff (a la Quaife) would be difficult, at best. I wonder if you'd have to source new half shafts that are longer.
	Appreciate 0 Quote

08-24-2007, 10:22 AM	#64
GoingTooFast Banned 89 Rep 1,247 Posts Drives: fat cars are still boats Join Date: Jun 2007 Location: compensating a fat car with horsepower is like giving an alcoholic cocaine to sober him up. iTrader: (0)	I think it was already posted elsewhere... BMW E-LSD
	Appreciate 0 Quote

08-24-2007, 10:40 AM	#65
mikeo Santa Fe Concorso 103 Rep 2,984 Posts Drives: '11 M-sport 328i, '13 X1 28i Join Date: Jul 2007 Location: Santa Fe, NM iTrader: (3)	So is this the dif that will be in the 135i? __________________ Santa Fe Concorso - The Southwest's Premier Automotive Gathering.
	Appreciate 0 Quote

08-24-2007, 10:43 AM	#66
Powerman Private First Class 4 Rep 122 Posts Drives: Join Date: Jul 2007 iTrader: (0)	Is this really the electronic limited slip they are talking about in the 135i? The one that has been talked about in the 135 is electronic, not mechatronic. The one posted is another type of actual limited slip, not electronically simulated. Other manufacturers have been using independent brake circuits to brake the slipping wheel for a while. That is nothing new. While the brochure is ambiguous, I does not seem like the mechatronic LSD is what they are talking about.
	Appreciate 0 Quote