LSD options for 6-cyl E39

[GREY59]

Yesterday I took my car to a local BMW shop to get an alignment and while I was there I was talking with the service manager about putting an LSD in my 528i. He told me that some European-market, 6-cyl diesel E39s came with an LSD in them. This was completely new information to me so I was wondering if anyone can anyone confirm whether this is true, and if so, how hard they are to find? I've been researching LSD options for my car for a little while now and it seems that the only option is to get one built, as the M5 LSD wont work, and you cant fit one from another series/chassis without some pretty serious modifications. Maybe I just havent done enough research so any and all advice is greatly appreciated.

[jicaino]

Yesterday I took my car to a local BMW shop to get an alignment and while I was there I was talking with the service manager about putting an LSD in my 528i. He told me that some European-market, 6-cyl diesel E39s came with an LSD in them. This was completely new information to me so I was wondering if anyone can anyone confirm whether this is true, and if so, how hard they are to find? I've been researching LSD options for my car for a little while now and it seems that the only option is to get one built, as the M5 LSD wont work, and you cant fit one from another series/chassis without some pretty serious modifications. Maybe I just havent done enough research so any and all advice is greatly appreciated.

All euro spec cars had the option of limited slip differentials. I've seen one early 535i (borderlining preproduction) with the small E34 differential (IIRC the 188) with 25% lockup. Said "small" diff is a lot like what 6 cyls E39 have. I don't know wether it was that way from the factory or not, and owner was unclear as he wasn't the first owner.

The cheapest, sanest and easiest option is getting a torsen unit (wavetrac, quaiffe) and install it in your differential.

[danb1979]

NO E39 came with an LSD from factory; so whoever told you that is wrong...

Plenty of info on Google

For me, if it's an every day road going car; it really doesn't need an LSD. But each to their own

Quaife, MFactory would be the diffs I'd be looking into if I wanted to go down that route

[BimmerBreaker]

Even if the diesels had an LSD (doesn't look like they do according to RealOEM) the ratio of the diesel diffs is 2.35 - you definitely don't want that

Aftermarket is the best option - or use a V8 E39 rear-end, but then you have to worry about the driveshaft too... and the V8 ratios arent ideal for the I6 either

[jicaino]

Even if the diesels had an LSD (doesn't look like they do according to RealOEM) the ratio of the diesel diffs is 2.35 - you definitely don't want that

Aftermarket is the best option - or use a V8 E39 rear-end, but then you have to worry about the driveshaft too... and the V8 ratios arent ideal for the I6 either

My 540i, the M5 and the 523i have all the same rear end ratio. So much as for "not ideal ratios"

[BimmerBreaker]

Just because they came with those ratios, doesn't mean they are "ideal". The V8's came with 6 speed manuals, whereas the I6's got 5 speeds - so this affects the diff ratio drastically, as they need the cars to be geared to drive on the highway at an acceptable RPM. The I6's are better off with a slightly more aggressive ratio to help with acceleration, such as the 3.46 ratio that some M54 cars got, manuals didn't get them because of the lack of 6th gear though. So not exactly apples to apples comparing a 6 speed V8 to 5 speed I6

Also according to realoem the manual 523 came with a 3.07 vs the 3.15 for M5 and some 540i's. Automatic 523's got a 3.15
In any case, going from his current ratio to a 2.35 would be a MASSIVE decrease in acceleration and overall performance feel. His highway fuel economy would increase though. I sort of doubt that's what hes after though

...slap a 3.46 in the back of that 523 and you'd probably enjoy the car even more. Put a 6 speed gearbox in front of the 3.46 and you've got just about a perfect E39 for daily driving. I'd prefer a 2.8 personally though, for the extra oomph, but I doubt the .5L is super noticeable

[jicaino]

Just because they came with those ratios, doesn't mean they are "ideal". The V8's came with 6 speed manuals, whereas the I6's got 5 speeds - so this affects the diff ratio drastically, as they need the cars to be geared to drive on the highway at an acceptable RPM. The I6's are better off with a slightly more aggressive ratio to help with acceleration, such as the 3.46 ratio that some M54 cars got, manuals didn't get them because of the lack of 6th gear though. So not exactly apples to apples comparing a 6 speed V8 to 5 speed I6

Also according to realoem the manual 523 came with a 3.07 vs the 3.15 for M5 and some 540i's. Automatic 523's got a 3.15
In any case, going from his current ratio to a 2.35 would be a MASSIVE decrease in acceleration and overall performance feel. His highway fuel economy would increase though. I sort of doubt that's what hes after though

...slap a 3.46 in the back of that 523 and you'd probably enjoy the car even more. Put a 6 speed gearbox in front of the 3.46 and you've got just about a perfect E39 for daily driving. I'd prefer a 2.8 personally though, for the extra oomph, but I doubt the .5L is super noticeable

Yawn...

the V8 manuals came with 2.93 and the same tranny as the I6 too, you just think of all V8 as 4.4 or S62. I'm referring to 535i manuals.

There's no such thing as "ideal ratio" except for a close ratio tranny where your 1st gear combined with your rear end ratio doesn't exceed 10:1 and no gasoline (petrol) bimmer came so equipped (Closest ever were the dogleg M30s). All of you saying "there's no need for a lsd" obviously never drove thru mud, unpaved mountain roads or gravel, or in your less-than-ideal road conditions. Some of us use the car, you know, to do some actual driving, not doughnuts or quarter mile pulls...

[danb1979]

Yawn...

the V8 manuals came with 2.93 and the same tranny as the I6 too, you just think of all V8 as 4.4 or S62. I'm referring to 535i manuals.

There's no such thing as "ideal ratio" except for a close ratio tranny where your 1st gear combined with your rear end ratio doesn't exceed 10:1 and no gasoline (petrol) bimmer came so equipped (Closest ever were the dogleg M30s). All of you saying "there's no need for a lsd" obviously never drove thru mud, unpaved mountain roads or gravel, or in your less-than-ideal road conditions. Some of us use the car, you know, to do some actual driving, not doughnuts or quarter mile pulls...

You sound a bit hurt; you ok hun?

I'm one of those that said there's no need for an LSD in an every day 'road going' car and I stand by that!

The OP or anyone else hasn't mentioned about driving in mud/on dirt tracks or 'unpaved mountain roads'... If you're going to be doing a lot of that, you're not going to be using a RWD saloon generally... Anyone in that situation would have a 4x4...

For a car that's simply used on the roads for every day driving; no track days or 1/4 miles runs etc; an LSD is simply not required... If it was, BMW would have fitted them!

[jicaino]

You sound a bit hurt; you ok hun?

Well if you must turn this into a pissing contest, sir, I'll point out to your stupid comment of no E39 having LSD. Where does that imbecillic statement leaves the M5?

I'm one of those that said there's no need for an LSD in an every day 'road going' car and I stand by that!

The OP or anyone else hasn't mentioned about driving in mud/on dirt tracks or 'unpaved mountain roads'... If you're going to be doing a lot of that, you're not going to be using a RWD saloon generally... Anyone in that situation would have a 4x4...

For a car that's simply used on the roads for every day driving; no track days or 1/4 miles runs etc; an LSD is simply not required... If it was, BMW would have fitted them!

Well, because sir BS's-a-lot doesn't approve of the use we give to the car we'll be forced to boy a stupid 4x4 truck, honey! No, it doesn't matter if we've been already driving RWD E39 sedans for about 650000km in this sort of enviroment/way, this guy in Lancashire (Yes babe, he's probably related to those holes John Lennon mentions...) told me off on the internet so after pondering much I'll cease and desist.

BMW didn't offered LSDs because they were pushing for the ill conceived ASC+T and DSC. On E34's they offered the option and about 35% of the E34 you find are fitted with that, and all of a sudden they aren't needed? I guess you buy into the lifetime fluids crap, and other stuff BMW did? IMO it's unforgivable that a car like the E39 didn't come with LSD as standard. Also, when you guys find a car that has manual seats, why do you retrofit electric ones? no one needs power seats, or TV board monitors, or... (insert every option in the E39 daten) yet one of the things that most of us drives BMWs is because you can pretty much have it your way.

On track with OP's post, I just stated that Euro LHD cars have the option of LSD. Not just diesels. The only one I've seen didn't look original to me, but it was a car borderlining pre production and BMW oftens does funky stuff around production changes. There's no special options for diesels regarding drivetrain (unless you consider longer differential ratios a special option, which automatic diesels had, option code 203, which would revert the 2.80ish rear end ratio for 530d autos to the very long 2.30something or even 2.20something, I don't recall now). E39 daten states also 209 for 25% limited slip differential...

On a marginal note, your touring it's just gorgeous, IMHO just shy of perfect because the steering wheel is on the wrong side of the cabin.

[jicaino]

...slap a 3.46 in the back of that 523 and you'd probably enjoy the car even more. Put a 6 speed gearbox in front of the 3.46 and you've got just about a perfect E39 for daily driving. I'd prefer a 2.8 personally though, for the extra oomph, but I doubt the .5L is super noticeable

A) there's already a 3.46:1 fitted I 6: the 528i
B) The 523i manual it's pretty darn close to perfect for daily as it is. I only fitted a LWFW and better clutch and decatted it and it's just perfect IMHO. Classy, tame, a very good maneered car for big city traffic.
C) that "528i is better than 523i because 500c more" is just infantile. It's only less than 300cc more (b25 vs. b28 or exactly 2494cc vs 2793cc) and the 528i were geared shorter in order to make them look like they're faster. Matter of fact, a quicker revving engine with a longer final drive beats the "larger displacement more powerful" engine paired with a shorter final drive.

If anything, I'll upgrade the transmission to a ZF 6 speeds in the future,but leaving the final gearing as is.

[BimmrMeUpSnotty]

Pssst…… I too sometimes joke that right hand drive cars have the steering wheel on the wrong side of the car, only because we drive on the right side of the road. I’m sure, Dan, and the rest of the world that drives on the left side of the road, say the same thing about our steering wheels.
I have owned quite a few right hand drive cars, MGB’s, and the older Mini Coopers. Just such an odd feeling, driving them in a country where we drive on the right side. Passing a big truck out on a country road can be a leap of faith for that moment when you pull out onto the oncoming lane, I used to pull onto the shoulder, get a good look, then leap and pull out. But usually just didn’t let myself get too close to the rear of the vehicle in front of you. But still a small cliffhanger.

[jclausen]

A 6 cylinder would not be benefit from an lsd I drive my car return the twisties five days a week and it drives just fine without an lsd

[BimmrMeUpSnotty]

It will still drive better with a limited slip, no matter what…..

[BimmerBreaker]

Yeah these cars would absolutely benefit from an LSD but only if you drive them in a manner in which you are near the limit of traction. Many people with E39's will not be near this limit

IMO it's unforgivable that a car like the E39 didn't come with LSD as standard.

Yes 1000%. The lack of LSD is the only real drawback to an E39. I don't know why it wasn't at least an option...

C) that "528i is better than 523i because 500c more" is just infantile. It's only less than 300cc more (b25 vs. b28 or exactly 2494cc vs 2793cc) and the 528i were geared shorter in order to make them look like they're faster. Matter of fact, a quicker revving engine with a longer final drive beats the "larger displacement more powerful" engine paired with a shorter final drive.

I've driven many 2.5's, 2.8's and 3.0's - and just personally, for a car on the heavier side like an E39, I do prefer the extra displacement the 2.8 gives you - I can really feel the difference in torque. In Z3's for example I honestly prefer the smaller engines, the "2.3" and the 2.5 as they are square engine designs with great revving characteristics as you touch on. At the end of the day though any BMW I6 from this era is a pretty stout motor, it's hard to go wrong with any of them. They all feel faster than the numbers on paper would suggest. And the M52B25TU is one of my favorite engines from that era to be perfectly honest. It's M54 big brother 2.5 isn't too bad either

And if you take the shorter gears from the 528i into a 523 that should make the 523 even better, no?

[jicaino]

A 6 cylinder would not be benefit from an lsd I drive my car return the twisties five days a week and it drives just fine without an lsd

20180915_142146.jpg
I can live without LSD but it will be better to have one.

It will still drive better with a limited slip, no matter what…..

Yessir! There's no need to go offroad for the E39 to perform poorly, you just go and back up a wet or slippery stone driveway at a greater than 5 degrees angle and you'll find how useful a LSD could be.

Yeah these cars would absolutely benefit from an LSD but only if you drive them in a manner in which you are near the limit of traction. Many people with E39's will not be near this limit

Yes 1000%. The lack of LSD is the only real drawback to an E39. I don't know why it wasn't at least an option...

I've driven many 2.5's, 2.8's and 3.0's - and just personally, for a car on the heavier side like an E39, I do prefer the extra displacement the 2.8 gives you - I can really feel the difference in torque. In Z3's for example I honestly prefer the smaller engines, the "2.3" and the 2.5 as they are square engine designs with great revving characteristics as you touch on. At the end of the day though any BMW I6 from this era is a pretty stout motor, it's hard to go wrong with any of them. They all feel faster than the numbers on paper would suggest. And the M52B25TU is one of my favorite engines from that era to be perfectly honest. It's M54 big brother 2.5 isn't too bad either

And if you take the shorter gears from the 528i into a 523 that should make the 523 even better, no?

I've driven B23, B28 (both non TU) and I don't feel much of a difference if they're geared equal. Hell, I don't feel much of a difference if the B25 is geared lower, since it has like 230 kg less than the B28. Now after TU, with double vanos, the difference starts to show. Plus it gets bigger, like 2.5 to 3 liters. Now there's no need for BMW to undermine the B25 because the B30 makes a considerable amount of difference, enough for the figures not having to be oomped on the "larger, better" engine. I'm not a fan of undersquare engines, if I'd still be into that I'd have stuck with the slant six. I'd like to either turbo the B25 or to build it with hotter cams and headers, and a tad higher compression ratio. Say, 11.2~11.5 and S50 cams. Not a big fan of overgeared cars. If I'd still be into that I'd have a '68 charger.

[chuckesteeze]

I'd like to sidestep the issue of whether an LSD is needed and ask about how to acquire one. I'm about to undertake a manual swap on my 525iT using a ZF out of a 530i donor car. The diff on my wagon will do for now, but if I'm to change it out for something with a different final drive ratio eventually, I might as well go LSD. (FWIW I feel this is further justified given my longterm plans for the car: M54b30 and potentially boost.)

Who are some of the vendors out there I could contact? A buddy of mine used Synchrotech for his ZHP, so there's one. But I'd love to hear what other options there are.

[jicaino]

I'd like to sidestep the issue of whether an LSD is needed and ask about how to acquire one. I'm about to undertake a manual swap on my 525iT using a ZF out of a 530i donor car. The diff on my wagon will do for now, but if I'm to change it out for something with a different final drive ratio eventually, I might as well go LSD. (FWIW I feel this is further justified given my longterm plans for the car: M54b30 and potentially boost.)

Who are some of the vendors out there I could contact? A buddy of mine used Synchrotech for his ZHP, so there's one. But I'd love to hear what other options there are.

Quaiffe and wavetrac if you don't want to enter a whole new axles and driveshaft parts mix and match game

[anthonyk03]

you could contact https://www.koalamotorsport.com/ i have a LSD in my auto 530i and it was done by them

[blarf]

I've driven many 2.5's, 2.8's and 3.0's - and just personally, for a car on the heavier side like an E39, I do prefer the extra displacement the 2.8 gives you - I can really feel the difference in torque. In Z3's for example I honestly prefer the smaller engines, the "2.3" and the 2.5 as they are square engine designs with great revving characteristics as you touch on. At the end of the day though any BMW I6 from this era is a pretty stout motor, it's hard to go wrong with any of them. They all feel faster than the numbers on paper would suggest. And the M52B25TU is one of my favorite engines from that era to be perfectly honest. It's M54 big brother 2.5 isn't too bad either

Wut? The 2.8L is square (84 mm bore and stroke), 2.5L is oversquare (84 mm bore, 75 mm stroke), and the 3.0L is undersquare (84 mm bore, 89.6 mm stroke).

[Bwingnutt]

Well I have a e39 540 that does see autocross . A lsd diff would be a plus coming out of corners. Started a 6 spd swap the other day and figure my other m62 tu motor is what I will pair with the manual box. Still hope the 160 mph mark is doable ( On a closed coarse ) The lsd is next on the list. Closest thing to a M5 that I will ever own.

[scottieducati]

I absolutely adore my WaveTrac LSD (540iT/6). Can’t recommend them, and diffsonline, highly enough.


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[StephenVA]

a 525/528 can not even spin its tires when shod with a quality tire. Exceptions: SNOW, ICE, LOOSE GRAVEL, 90 Degree turns under full throttle, full throttle and power braking at a light in the rain. (Trust me, I try... )

If I was buying the car new would I check the box for the optional LSD? You bet.

Now an X5 4.8is under full throttle with the traction control turned off in the snow is a hoot. Rooster tails of snow out 20 ft behind you.

[BimmrMeUpSnotty]

And…… You did this on your pristine X5? Or did you con Mark to do it in his?

[StephenVA]

Mine. I don't think his is ever driven other than for annual State Safety and Emissions testing. For that event, he runs them up and down the Greenway to Leesburg and back to warm up the engine and tires. He always calls me and expresses the love for the full throttle feeling between 65-120 MPH. Carbon removal Italian style.

[carcrazyethan]

The OP or anyone else hasn't mentioned about driving in mud/on dirt tracks or 'unpaved mountain roads'... If you're going to be doing a lot of that, you're not going to be using a RWD saloon generally... Anyone in that situation would have a 4x4...

I'd much rather "offroad" in my wagon than a silly 4x4, so you're wrong here.