540i / 6 3.64 lsd question

[Dave95b]

Hey Fest. I'm still actively looking for a replacement for my 95 525i. I ran across a 95 540i/6 with 120k for $6k. Lots of upgrades to include GC coilovers, suspension rebuilt, and bushings replaced. Current owner says it has a 3.64 Dinan. I haven't done any lsd mods on any of my cars so what does it equate to versus the stock 3.15 other than higher torque?

Only problems are stick 32mm nut so telescoping steering wheel doesn't currently work and the SRS light is on due to accidentally coming out of the socket when the car was on. Lots of nice mods to the car. I've been looking at e39s, but I just can't get away from the awesomeness of the e34. Any input is appreciated.

[The Night Rider]

3.64 seems really high, isn't the stock one meant to be 2.93? My tiny M50B20 only has a 3.46 from factory and feels short.

Either way it means you will have to shift up the gears (especially first and second) quickly as all the gears will effectively be shorter. You will also get poorer gas mileage on the highway as it will be revving relatively high even in sixth gear, of course this means lower top speed.
Lower top speed is compensated by better acceleration.

Easier to destroy your rear tyres as well, this is a positive perhaps?

Hope this is of some use to you.

[ross1]

20% higher revs than a 2.93. First gear will be a stump puller and probably useless. The long overdrive in the 6 speed gearbox usually has the engine loafing in sixth with the 2.93. I forgot the revs mine was at various speeds but it shouldn't be anything to worry about. I'd guess 3k will be 80mph or so just like most others.

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3.64 seems really high, isn't the stock one meant to be 2.93? My tiny M50B20 only has a 3.46 from factory and feels short.

Either way it means you will have to shift up the gears (especially first and second) quickly as all the gears will effectively be shorter. You will also get poorer gas mileage on the highway as it will be revving relatively high even in sixth gear, of course this means lower top speed.
Lower top speed is compensated by better acceleration.

Easier to destroy your rear tyres as well, this is a positive perhaps?

Hope this is of some use to you.

I'm not so sure of this. The car doesn't have enough power to pull to redline in sixth with the 2.93. Those who've tried will certainly offer their experience and what revs it tops out at.

[imae30driver]

20% higher revs than a 2.93. First gear will be a stump puller and probably useless. The long overdrive in the 6 speed gearbox usually has the engine loafing in sixth with the 2.93. I forgot the revs mine was at various speeds but it shouldn't be anything to worry about. I'd guess 3k will be 80mph or so just like most others.

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I'm not so sure of this. The car doesn't have enough power to pull to redline in sixth with the 2.93. Those who've tried will certainly offer their experience and what revs it tops out at.

you just run out of room lol... "Eventually" it will get there, or nearly. Wiki says 181 mph delimited hahaha..

Not the point, anyways. I had the stock 2.93 and it was very good. Have the 3.15 lsd and love it. The perfect all rounder.

Having done swaps on other cars including 3.15 to 3.91 i can get an idea of what its like. Its wicked. Get it!

On the street it will rip 0-60, thanks to 6th gear it should still settle down a bit at 65mph but over 75mph on the freeway it may be kinda buzzy. Id say get it! worst case case scenerio you trade me for my 3.15 lsd as im primarily a drag/short track racer anyways lol. Or find the one ya want.

[BruinBimmer]

For a 540/6, 3.15 is perfect and 3.64 is overkill. 3.15 puts you in a sweet spot on the freeway to gently pass in 5th or 6th, or romp on it in 3rd without excessive speeding. 3rd with the 2.93 sits on the lower end of the powerband when passing on the freeway, but downshifting to 2nd for 5500 - 7000 rpm is a little unnecessary. 3.64 seems noisy, unnecessary, excessive wheelspin (have enough of that with S3.15), and ruins already-meh V8 mpg. Not sure if they made 3.64 in LSD, so you may just have one hell of a one tire fryer.

[me78569]

there is no way on gods green earth than a 540 will do 181 mph. It might in theory with the gearing, but it stops gaining speed at 16x mph with a 3.15 and even less with a 2.93.

I can say that I would have liked to try a 3.64. The 3.15 was an ok ratio, but honestly after 3rd the car really fell off. with the 3.64 I feel like 4th would still pull well and still have a top speed of 177, again doubt the m60 can pull the e34 that fast, but at least you get more usable rpms.

as for rpms at 75mph you will sit at 2580 rpms with a 3.15 and 2975 with a 3.64. still 2 shifts to 60 if you wrap it out.

http://i879.photobucket.com/albums/ab360/me78569/Capture_zps8105c074.png (http://s879.photobucket.com/user/me78569/media/Capture_zps8105c074.png.html)

If you car doesn't see a lot of highway miles then a 3.64 would be a lot of fun. Even if you did see a lot of highway miles it wouldn't be terrible, not ideal, but only 400 rpm more than the 3.15 No doubt it would be pretty high strung, but it just depends on what you want out of your car.

[Sam Son]

With the overdrive 6th that the 540 has it should be fine. It will be a hoot to drive. BIG improvement over the stock 2.93 or even the 3.15. I have a 3.64 in my car and with a 1:1 5th it is certainly high strung but with a 6th gear it would be perfect. A 3.23 is also pretty nice.

[E34nication]

there is no way on gods green earth than a 540 will do 181 mph. It might in theory with the gearing, but it stops gaining speed at 16x mph with a 3.15 and even less with a 2.93.

I can say that I would have liked to try a 3.64. The 3.15 was an ok ratio, but honestly after 3rd the car really fell off. with the 3.64 I feel like 4th would still pull well and still have a top speed of 177, again doubt the m60 can pull the e34 that fast, but at least you get more usable rpms.

as for rpms at 75mph you will sit at 2580 rpms with a 3.15 and 2975 with a 3.64. still 2 shifts to 60 if you wrap it out.

http://i879.photobucket.com/albums/ab360/me78569/Capture_zps8105c074.png (http://s879.photobucket.com/user/me78569/media/Capture_zps8105c074.png.html)

If you car doesn't see a lot of highway miles then a 3.64 would be a lot of fun. Even if you did see a lot of highway miles it wouldn't be terrible, not ideal, but only 400 rpm more than the 3.15 No doubt it would be pretty high strung, but it just depends on what you want out of your car.

I think this calculator is a little off. Here's a screenshot from a vid back when my car had a 3.64 in it (car is in 3rd gear). 3rd gear was good for about 80mph @ 7k RPM's. My speedo was about 3mph high based on GPS... I also ran it to the top of 6th (think I may have shut down around 6600RPM's or so, can't remember it was a LONG time ago, but I was just past 160 on the speedo.

The 3.15 calculation seems to be off as well. With the stock rear end my car would hit the 7k rpm limiter in 3rd gear right as it hit the traps, and my trap speed was 101.75... and that was on the stock 15's. 3.64 was with a 255/40/17 rear tire.

http://i537.photobucket.com/albums/ff334/jkc212121/364E34_zps048db92e.jpg

Here's the vid, starting in 2nd gear.
https://www.youtube.com/watch?v=DuUE2R5DP80

[me78569]

I am guessing the tire size I had threw the numbers off a bit. I used 225/60/15 is that correct?

Edit:


Looks like the gearing numbers for the 420g don't agree on the internet. Anyone verify what the gearing actually is for 1st-6th?

[M3 Euro LTW]

Such a subjective question.

I recently had a fresh alusil swapped in, and at the same time had a 3.23 LSD put in. Great upgrade, not buzzy at all.

I think with 6 th you will be fine, the primary difference is you will actually use 6th gear, whereas many people might not ever shift out of 5 since engine with 2.91 or whatever is hardly begging rpm wise to leave 5 at most highway speeds.

Theoretically, mpg doesn't have to suffer at legal speeds vs someone who rarely used sixth

[BruinBimmer]

Why not use 6th? It doesn't have to be highway. On a big street with a 50mph speed limit, I can chug along in 6th between 50-55 around 1800-2000 rpm ish. Not that the OBC is completely accurate, but I can hit 26-28 mpg at that speed in 6th, and my trip odometer did reflect that when I filled up at the pump. Sure, the motor bogs at that rpm, but who would buy a manual and complain about downshifting to make a yellow light or make a pass?

I agree this is all subjective, so IMO S3.15 is the perfect compromise of daily driveability/mpg/performance. Plus, if anyone plans to add any considerable amount of power, a 3.64 could render 1st and 2nd pretty useless, depending on your tires.

Regardless, I am curious what times a chipped-but-otherwise stock 540/6 with a 3.64 could put down on the strip. I think Kris holds one the best stock-ish times, using a 3.15 to get 13.9X.

[Offtopic]

Hey guys, I actually own the car the OP is referencing. 1st gear is defiantly optional even at a slight incline. At the altitude I'm at though it's nice to have the extra torque. If I were to keep the car I would swap a 3.15 in, I even found one at the local pick and pull a couple weeks ago for $70 in a 1989 750. The current diff does have its benefits though like 70k miles, and a 40% lock up. It also may be worth a decent amount of money to the right person if it were to be sold. In my opinion it would be great for auto-crossing.

[me78569]

you're in the springs and have a 540/6 with a 3.64? I would love to take a ride in that.


by the way that 3.15 is an open diff you found.......Greg and I did our best to pull it without the right tools :rofl however the tag lacked the s.

[E34nication]

Hey guys, I actually own the car the OP is referencing. 1st gear is defiantly optional even at a slight incline. At the altitude I'm at though it's nice to have the extra torque. If I were to keep the car I would swap a 3.15 in, I even found one at the local pick and pull a couple weeks ago for $70 in a 1989 750. The current diff does have its benefits though like 70k miles, and a 40% lock up. It also may be worth a decent amount of money to the right person if it were to be sold. In my opinion it would be great for auto-crossing.

Nice, sounds like a very awesome car.


Such a subjective question.

I recently had a fresh alusil swapped in, and at the same time had a 3.23 LSD put in. Great upgrade, not buzzy at all.

I think with 6 th you will be fine, the primary difference is you will actually use 6th gear, whereas many people might not ever shift out of 5 since engine with 2.91 or whatever is hardly begging rpm wise to leave 5 at most highway speeds.

Theoretically, mpg doesn't have to suffer at legal speeds vs someone who rarely used sixth


Why not use 6th? It doesn't have to be highway. On a big street with a 50mph speed limit, I can chug along in 6th between 50-55 around 1800-2000 rpm ish. Not that the OBC is completely accurate, but I can hit 26-28 mpg at that speed in 6th, and my trip odometer did reflect that when I filled up at the pump. Sure, the motor bogs at that rpm, but who would buy a manual and complain about downshifting to make a yellow light or make a pass?

I agree this is all subjective, so IMO S3.15 is the perfect compromise of daily driveability/mpg/performance. Plus, if anyone plans to add any considerable amount of power, a 3.64 could render 1st and 2nd pretty useless, depending on your tires.

Regardless, I am curious what times a chipped-but-otherwise stock 540/6 with a 3.64 could put down on the strip. I think Kris holds one the best stock-ish times, using a 3.15 to get 13.9X.

It was a 14.0 at a little under 102, but that was with stock gearing as well. Only modification was a Conforti chip (car was even on 15's). I didn't run the car again when it was close to stock with the 3.15.

3.15 is a great compromise gear, but the real gain is with the LSD. With a 3.15 the car was still capable of 26-27mpg on the highway at 75mph, when I had the 3.64 that figured dropped to 20-21mpg on the highway at 75mph. It was too much IMO for a DD type street car. I wouldn't mind having a S3.64 in my car the way it sits now, haven't had much luck finding one for under $1k.

[The Night Rider]

there is no way on gods green earth than a 540 will do 181 mph. It might in theory with the gearing, but it stops gaining speed at 16x mph with a 3.15 and even less with a 2.93.

I can say that I would have liked to try a 3.64. The 3.15 was an ok ratio, but honestly after 3rd the car really fell off. with the 3.64 I feel like 4th would still pull well and still have a top speed of 177, again doubt the m60 can pull the e34 that fast, but at least you get more usable rpms.



Yes I forgot to take into consideration weather or not the engine actually has the power to reach red line in top gear.

[BruinBimmer]

Hey guys, I actually own the car the OP is referencing. 1st gear is defiantly optional even at a slight incline. At the altitude I'm at though it's nice to have the extra torque. If I were to keep the car I would swap a 3.15 in, I even found one at the local pick and pull a couple weeks ago for $70 in a 1989 750. The current diff does have its benefits though like 70k miles, and a 40% lock up. It also may be worth a decent amount of money to the right person if it were to be sold. In my opinion it would be great for auto-crossing.

For most courses, no. For almost every course, leaving it in 2nd with a 3.15 is the most ideal. You never need to shift down to 1st, you almost always use all of 2nd gear's powerband (rarely ever dropping out of it), and rarely need to shift to 3rd (most of the time, just holding it on the rev limiter for .25-.5 sec is faster). With the 3.64, you may hit the top of 2nd at 55, so that means you would need to grab 3rd briefly for nearly half of the corners out there, thus being stuck in the bottom of the powerband much more often. On top of all that, autocross surfaces are tough enough to find grip with a S3.15, so a 40% lockup 3.64 would just make most drivers go in circles at every corner exit.

If by 'great' you mean 'one helluva challenge', then sure. Like Kris said, a 40% lockup S3.64 would be more suited for a car road racing on slicks/semi-slicks, where there is enough grip to actually use all that extra torque and lockup.

Not trying to bust any balls, just trying to put useful insight out there and not let people think that they can slap that diff on for quick, easy autocross times.

[IronmanE30]

I have this diff in my 540/6 and love it. First gear is a little too low geared but when you hit second it's a beast. I also have GC coil overs with Koni shocks and they work well. Mine springs are kind of stiff but I like the ride. I would not let the gearing keep you from buying the car. Drive it and if you don't like the low gears swap in another diff. If I am not having fun with the car it gets decent gas milage for an M60.

Cheers,

Jim

[E34nication]

If you don't like the diff I would be interested in it.

This sounds like a great car for the price... Looks to be very clean.

[GazM3]

This is what diff I have in the m3 and when in NA form it was great with the 6 spd and not buzzy at all. It would be a good mod on a std power e34 540i if it was only mildly powered up form. With a functioning LSD and good rubber it will put power down fine in first unless provoked. Ideally u would have the chip that allows 7000rpm.
In my 540 I have the ess supercharger so 3.15 seems about right I could go shorter diff 3.45 now but once I put the Intercooler and up the boost a little the 3.15 will be good.

[Parkypine]

Where did you source the s3.23 from? I want a taller gearing than s3.15 but I am hesitant about getting the s3.64. s3.23 sounds ideal for my taste.

I understand that s3.15s came from e32s and I am pretty sure no e32s came with s3.23... did you source it from an e31?

Also, if anyone is interested, i have an open 3.64 for sale, not looking much for it (if you want to, god forbid, weld the diff for tire burning applications or just want the gearing in general, hit me up!)

[K Fox]

Where did you source the s3.23 from?

The only way I know how to do that on a V8 car is a modded 530 - those use the medium case diffs, and you have a lot more variety in the ratios offered. If that's not the case, I'm also quite curious - I was under the strong impression that large case diffs had rather limited gear ratio choices, and 3.23 wasn't on that list as far as I know...

Fox

[Ernie D]

I'm also needing some advice on a gear setup also, sorry, I'm not trying to steal your thread, but I currently have a m60b30 in my car. I do plan on doing a B40 swap within the next year but I'm planning on having a little fun with the 3 liter while its in the car.
I'm planning on auto crossing my car,so I would need a lower gear ratio but I'm not sure what ratio I would benefit the most from, I'm still wanting a half decent DD also but I know I'm gonna compromise fuel mileage for bottom end grunt. LSD would be a plus for me. And is there a post or something to steer me in the right direction on which car to find the ratio I need to get?

[Parkypine]

The only way I know how to do that on a V8 car is a modded 530 - those use the medium case diffs, and you have a lot more variety in the ratios offered. If that's not the case, I'm also quite curious - I was under the strong impression that large case diffs had rather limited gear ratio choices, and 3.23 wasn't on that list as far as I know...

Fox

I've heard that e46 large case lsds swap over too, I am not sure though, I think they have factory large case s3.23? Not sure though, either way I realy really really need to graduate from open 2.93.

WHY ARE LARGE CASE DIFFS SO EXPENSIVE AND HARD TO FIND

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I'm also needing some advice on a gear setup also, sorry, I'm not trying to steal your thread, but I currently have a m60b30 in my car. I do plan on doing a B40 swap within the next year but I'm planning on having a little fun with the 3 liter while its in the car.
I'm planning on auto crossing my car,so I would need a lower gear ratio but I'm not sure what ratio I would benefit the most from, I'm still wanting a half decent DD also but I know I'm gonna compromise fuel mileage for bottom end grunt. LSD would be a plus for me. And is there a post or something to steer me in the right direction on which car to find the ratio I need to get?

Buy my 3.64 :D should be plenty tall, but not stupidly tall for such applications. Are you going to swap the diff before or after the swap? If I am not mistaken, 530is use medium case.

[imae30driver]

I've heard that e46 large case lsds swap over too, I am not sure though, I think they have factory large case s3.23? Not sure though, either way I realy really really need to graduate from open 2.93.

WHY ARE LARGE CASE DIFFS SO EXPENSIVE AND HARD TO FIND

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Buy my 3.64 :D should be plenty tall, but not stupidly tall for such applications. Are you going to swap the diff before or after the swap? If I am not mistaken, 530is use medium case. Although a large case lsd is worth 500$~ an open end is only worth about 50$...

so gears are cheap, just not lsd.

[Ernie D]

I've heard that e46 large case lsds swap over too, I am not sure though, I think they have factory large case s3.23? Not sure though, either way I realy really really need to graduate from open 2.93.

WHY ARE LARGE CASE DIFFS SO EXPENSIVE AND HARD TO FIND

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Buy my 3.64 :D should be plenty tall, but not stupidly tall for such applications. Are you going to swap the diff before or after the swap? If I am not mistaken, 530is use medium case.
It has a medium case, I'm planning on changing it out before I do my B40 swap, I know the flanges are different sizes between the large and medium case, was lsd a factory option with cars that didnt have ASC or was it avalible for ASC cars also?

[Parkypine]

It has a medium case, I'm planning on changing it out before I do my B40 swap, I know the flanges are different sizes between the large and medium case, was lsd a factory option with cars that didnt have ASC or was it avalible for ASC cars also?

If I am not mistaken, the only large case LSD offered for e34s were in m5s. No 540is came with LSDs even the Msport unicorns.

[Ernie D]

If I am not mistaken, the only large case LSD offered for e34s were in m5s. No 540is came with LSDs even the Msport unicorns.

Is there a medium case lsd offered? Or is that just a large case?

[imae30driver]

It has a medium case, I'm planning on changing it out before I do my B40 swap, I know the flanges are different sizes between the large and medium case, was lsd a factory option with cars that didnt have ASC or was it avalible for ASC cars also?
I thought a few rare winter package models typically with heated seats as well did??? But darn near none

[Parkypine]

Is there a medium case lsd offered? Or is that just a large case?

oh pfft medium case lsds were offered left and right. not too hard to find and affordable

[GazM3]

The 3.23 ratio in large case came with the eurospec e36 m3 Evo. I swapped mine some time ago for 3.62 but may put the old ratio in when the supercharger building is finished as the low gears will be challenging with 500rwhp rather than 285!

[imae30driver]

The 3.23 ratio in large case came with the eurospec e36 m3 Evo. I swapped mine some time ago for 3.62 but may put the old ratio in when the supercharger building is finished as the low gears will be challenging with 500rwhp rather than 285!
God i want that!

trade me for my s3.15 lol

[bubba966]

Where did you source the s3.23 from?

Large case S3.23's were in the 6 speed E34 M5's.

[PorscheH6]

Large case S3.23's were in the 6 speed E34 M5's.



$$$$$$$$$$$$$$$$$$$

[B10 BITURBO]

20% higher revs than a 2.93. First gear will be a stump puller and probably useless. The long overdrive in the 6 speed gearbox usually has the engine loafing in sixth with the 2.93. I forgot the revs mine was at various speeds but it shouldn't be anything to worry about. I'd guess 3k will be 80mph or so just like most others.

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I'm not so sure of this. The car doesn't have enough power to pull to redline in sixth with the 2.93. Those who've tried will certainly offer their experience and what revs it tops out at.


BINGO..........

as i am driving with M70 in an E30 and the 1st gear i almost useless......... and i am using 3.46.. i know the car is Lighter but i think 3.15 is the best option
3.45 could also be used ,, and is ok as your car is more in weight vs mine

i am going to 2.93.. so i can use the 1.st and 2.nd in a proper way

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The 3.23 ratio in large case came with the eurospec e36 m3 Evo. I swapped mine some time ago for 3.62 but may put the old ratio in when the supercharger building is finished as the low gears will be challenging with 500rwhp rather than 285!

E34 M5 6g came also with 3.23... ALL 540 came with 2.93 but from early 94 USA spec only 540 auto came with 2.81 diff... the same ratio as E39 540 came with

IMO there is not so much difference between 3.15 or 3.23........ but automatic the 3.64 is stunning