R3VLimited Forums

Go Back   R3VLimited Forums > E30 Technical Forums > Engine & Drivetrain > Transmission & Driveline

Reply
 
Thread Tools Search this Thread
Old 04-28-2012, 11:22 PM   #16
Wanganstyle
R3VLimited
 
Wanganstyle's Avatar
 
Join Date: Apr 2010
Location: SF bay area
Posts: 2,798
Quote:
Originally Posted by cjdontthink View Post
Wangan are you capable of replacing the bearings on a diff? How hard is it?
Would you do it for some cash?
I do FULL custom diff builds for mostly track e36/46 m's and non m's. The budget is pretty expensive for the average e30 crowd - pm me if you are serious with what you would like and I can send you a quote.

A few locals in the 500-600rwhp range have my built units for street/track. One in the 1,000-1,100 rwhp range also.



Setting these up is Pretty time consuming

requires some very specific tools (or you may destroy your new races/bearings trying to install). I have had aborted projects by DIY-er's shipped to me to heal.

Custom center section fitting with proprietary steels also really should be done with reconfigured center lsd's.

Most e30's are running around on melted time bombs for diffs. All the 3.25 ratios are for example, almost all 3.73 units as well.
__________________
OBD1 M54/M52TU swap as a M50b25
Z4 non powered steering rack fits e30


Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine
Wanganstyle is offline   Reply With Quote
Old 04-28-2012, 11:26 PM   #17
Wanganstyle
R3VLimited
 
Wanganstyle's Avatar
 
Join Date: Apr 2010
Location: SF bay area
Posts: 2,798
Quote:
Originally Posted by e30leigh View Post
wow this is so interesting.... how would i gain a 75% locking 4.1 for my e30? and also the 188mm is that the medium case e30 diff?
168- small
188- medium
210- large.

If you wanted 75% locking you would need to run a custom ramp angle center section with 4 clutch discs and steels.

To compare bmw uses 4 Xlutch discs and steels for the Motorsports LSD unit but lock up is set at 40% accel and 25% deccel.

75% both ways is very high locking, pretty extreme Setup. My guys on the king of Europe pro drift circuit run something in this range (proprietary)

Also uping the Number of clutch disc Sets to 5 pairs with custom Case setup can make lockup in the 75% + range. .

The centers cannot be machined, they need to be precision ground.

Stock ramp angles are 45 degrees, with 4 disc pairs they yield 60% locking.

Do you have enough power to power over a 60% locking high lock diff? With two way action this will understeer dramatically compared to the stock setting by bmw for the car.

Are you setting up a drift car?
__________________
OBD1 M54/M52TU swap as a M50b25
Z4 non powered steering rack fits e30


Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine
Wanganstyle is offline   Reply With Quote
Old 04-29-2012, 02:06 AM   #18
e30leigh
E30 Addict
 
Join Date: Mar 2012
Location: auckland city, new zealand
Posts: 481
Quote:
Originally Posted by Wanganstyle View Post
168- small
188- medium
210- large.

If you wanted 75% locking you would need to run a custom ramp angle center section with 4 clutch discs and steels.

To compare bmw uses 4 Xlutch discs and steels for the Motorsports LSD unit but lock up is set at 40% accel and 25% deccel.

75% both ways is very high locking, pretty extreme Setup. My guys on the king of Europe pro drift circuit run something in this range (proprietary)

Also uping the Number of clutch disc Sets to 5 pairs with custom Case setup can make lockup in the 75% + range. .

The centers cannot be machined, they need to be precision ground.

Stock ramp angles are 45 degrees, with 4 disc pairs they yield 60% locking.

Do you have enough power to power over a 60% locking high lock diff? With two way action this will understeer dramatically compared to the stock setting by bmw for the car.

Are you setting up a drift car?
basically im building a car for some fun. i want to be able to drift it shall i feel the urge. i also want it to be track driven. and the odd drag day. the car will be street driven also. so a solid all rounder. and the power will be 300-350hp. turbo m20b25
e30leigh is offline   Reply With Quote
Old 04-29-2012, 06:52 AM   #19
Wanganstyle
R3VLimited
 
Wanganstyle's Avatar
 
Join Date: Apr 2010
Location: SF bay area
Posts: 2,798
Do you want the car to make LSD noises when you parallel park? It will with high locking conversion- the kaaz unit I was running prior was almost un-street able, everyone would ask me what the crazy lock up noise was turning.

Locals with 500-600rwhp are doing fine with 3 clutch discs and 40% lock up. Track /dd/ street driven and civilized. Gets sideways very easily too if setup correctly, although a e30/36 with ls7 will probably get sideways on will with drag slicks on the back.

75% locking is very heavy duty and not really suggested for street cars unless you have a fetish. It will be very fun for hooning though! And induce quite a bit of understeer on deccel if it's setup for 2-way action with symmetrical ramps.

hydrolic e brake? 2way high lock lsd +hydro e brake would be the d1 setup
__________________
OBD1 M54/M52TU swap as a M50b25
Z4 non powered steering rack fits e30


Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine
Wanganstyle is offline   Reply With Quote
Old 04-29-2012, 04:06 PM   #20
ROLLingKING
E30 Enthusiast
 
ROLLingKING's Avatar
 
Join Date: Apr 2011
Location: MD
Posts: 1,169
this thread is dope.

so u said something about most 3.73's are time bombs.
i want my lsd to just lock up nicely so what can i do to refreshen it or if it has to be opened up make it lock up more. add another clutch?
__________________
m20 is plenty. im simply a drifter.
build thread -- http://www.r3vlimited.com/board/showthread.php?t=206510
ROLLingKING is offline   Reply With Quote
Old 04-29-2012, 06:30 PM   #21
Jaxx_
E30 Mastermind
 
Jaxx_'s Avatar
 
Join Date: Dec 2009
Location: Durham, NC, USA
Posts: 1,773
is it possible to calculate max lockup torque?
__________________
'84 318i M10B18 | 93whp/90ftlbs | 147- Safari Beige | MS2E w/ LC, 2-Step
Jaxx_ is offline   Reply With Quote
Old 04-30-2012, 06:03 AM   #22
The Dark Side of Will
R3VLimited
 
Join Date: Jun 2010
Location: VA
Posts: 2,558
Quote:
Originally Posted by Wanganstyle View Post
Most e30's are running around on melted time bombs for diffs. All the 3.25 ratios are for example, almost all 3.73 units as well.
What exactly do you mean by this?
The Dark Side of Will is offline   Reply With Quote
Old 04-30-2012, 09:23 AM   #23
Wanganstyle
R3VLimited
 
Wanganstyle's Avatar
 
Join Date: Apr 2010
Location: SF bay area
Posts: 2,798
Quote:
Originally Posted by ROLLingKING View Post
this thread is dope.

so u said something about most 3.73's are time bombs.
i want my lsd to just lock up nicely so what can i do to refreshen it or if it has to be opened up make it lock up more. add another clutch?
Tear it apart and see how worn the clutch discs and steels are. Order thicker to make up for case wear. You can add extra discs/steels if you are drifting or doing other fun things with your car. the existing clutch discs and steels --->trash

3.73 LSD is fitted by bmw to a 5 speed 325i. Almost all of these are running original diff units from 1985-91 and the pinion bearings are close to done - most whining from diffs is this bearing angry and complaining.

The front pinion bearing is the first to go, its race also needs to be replaced at the same time.


the LSD internals are designed to wear out, its a setup of organic clutch discs and steels - most of the LSD units from manual transmisison bmw's I open up have extremely worn discs / melted organic material / smeared steels from melting. So doing burnouts, doughnuts, drag launches - all the fun things that owning an e30 allows you to do........diff hates it.

e36M LSD units are usually extremely worn, the steels often have heat spots and clutch discs will show signs of being worn out and just spinning.


Quote:
Originally Posted by The Dark Side of Will View Post
What exactly do you mean by this?

3.25, 3.73, 3.15/3.23 are from cars equipped with manual transmissions and a M30b34, M20b25, s52b32/s50b30. All of these are sporting engines with sporting owners; the functional materials inside are just like brake pads and rotors.

Fun engines = need brake pads more often. Same for diff


Quote:
Originally Posted by Jaxx_ View Post
is it possible to calculate max lockup torque?

you can build a jig to hold the pinion flange and a side axel flange fixed and make a fixture to measure breakaway torque. or you can block wheels in the air and jack up the rear to test it field style as they do for Spec e30
__________________
OBD1 M54/M52TU swap as a M50b25
Z4 non powered steering rack fits e30


Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

Last edited by Wanganstyle; 04-30-2012 at 09:34 AM.
Wanganstyle is offline   Reply With Quote
Old 04-30-2012, 10:37 AM   #24
The Dark Side of Will
R3VLimited
 
Join Date: Jun 2010
Location: VA
Posts: 2,558
Quote:
Originally Posted by Wanganstyle View Post
Tear it apart and see how worn the clutch discs and steels are. Order thicker to make up for case wear.
Oh, you were just talking about normal wear and tear.

Quote:
Originally Posted by Jaxx_ View Post
is it possible to calculate max lockup torque?
Quote:
Originally Posted by Wanganstyle View Post
you can build a jig to hold the pinion flange and a side axel flange fixed and make a fixture to measure breakaway torque. or you can block wheels in the air and jack up the rear to test it field style as they do for Spec e30
Well... Wouldn't that just measure the spring preload torque? The ramps allow the torque applied to the driveline to increase the torque the clutch packs can take... Meaning that as you apply more torque from the engine, the "lockup" torque increases. This leads to the rating of diffs by "% lock", meaning that the combo of ramp angle and number of clutch disks would result in the torque the clutch packs could apply being 25% of the torque applied *to* the unit. So if you end up with 2000 ftlbs at the axle in first gear (Engine torque * trans ratio * diff ratio), the unit would be capable of biasing that torque by up to 500 ftlbs difference left to right.
The Dark Side of Will is offline   Reply With Quote
Old 04-30-2012, 12:12 PM   #25
Wanganstyle
R3VLimited
 
Wanganstyle's Avatar
 
Join Date: Apr 2010
Location: SF bay area
Posts: 2,798
its simple and just measures the preloaded torque + static Mu yes.

the internal "locking" is more of a characteristic of the center section than anything else. - the stock e30 units are ramped to do the same thing both accel and deccel. The ramp angle can aid the clutches in locking up or prevent them from contacting (i.e. you have a 90 degree angle on deccel and the diff is = open when off throttle.

the sider gears slide on these ramps, the stub axels are mated into the spiders with splines.


the stock e30 ramp angles are 45deg. This is setup with a sideload spring and one clutch disc+steel each side.

the motorsports LSD has 4 clutch discs inside, no sideload springs.
its ramp angles are 45deg on accel and 55 deg on deccel. The stock diff setting will allow coasting and minimal to no lock up when in neutral - its unsprung.

if playing the spec e30 loading test game it would perhaps register nothing on breakaway, it can basically act as an open diff.

ZF differentials are setup this way in other cars; alfa, ferrari, porsche.

as far as how to rate/specify a diff, what kind of data are you trying to capture?

more clutch disc sets = grabbier feeling item like a KAAZ or cusco unit.

if one really wants a mathematical data point wouldnt a gear type or torsen be the best?
__________________
OBD1 M54/M52TU swap as a M50b25
Z4 non powered steering rack fits e30


Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine
Wanganstyle is offline   Reply With Quote
Old 04-30-2012, 12:44 PM   #26
The Dark Side of Will
R3VLimited
 
Join Date: Jun 2010
Location: VA
Posts: 2,558
Quote:
Originally Posted by Wanganstyle View Post
the sider gears slide on these ramps, the stub axels are mated into the spiders with splines.
Referencing the diagrams in your TIS link:
http://tis.spaghetticoder.org/s/view.pl?2/08/69

The square lugs on the sides of #9 components are driven by channels on the inside of #12. As they are driven, they push on the cross-shafts which cause the spider gears to push on the side gears... the same way an open diff works.
However, because of that power path, the torque through the unit controls how hard the #9 components are squeezing the clutch packs. Since the normal force on the clutch pack is proportional to the torque applied to the unit, the "lockup torque" of the unit is a fixed fraction of the torque being put through the unit.
If you all the coefficients of friction, you can calculate what this fraction is.
But a rating like "max lockup torque of 500 ftlbs" can not be applied because that torque varies with how much torque is applied to the unit.

A Torsen is a bit different in that the max torque in can bias to the wheel with more grip is a fixed ratio times the torque that the wheel with less grip can deal with.
The Dark Side of Will is offline   Reply With Quote
Old 04-30-2012, 01:00 PM   #27
Jean
Moderator
 
Jean's Avatar
 
Join Date: Aug 2006
Location: sacramento
Posts: 18,209
Still rocking your diff! I do need new ratio though lol
__________________
Mtech1 v8 build thread - https://www.r3vlimited.com/board/sho...d.php?t=413205



OEM v8 manual chip or dme - https://www.r3vlimited.com/board/sho....php?p=4938827
Jean is offline   Reply With Quote
Old 04-30-2012, 02:51 PM   #28
Wanganstyle
R3VLimited
 
Wanganstyle's Avatar
 
Join Date: Apr 2010
Location: SF bay area
Posts: 2,798
Quote:
Originally Posted by The Dark Side of Will View Post
Referencing the diagrams in your TIS link:
http://tis.spaghetticoder.org/s/view.pl?2/08/69

The square lugs on the sides of #9 components are driven by channels on the inside of #12. As they are driven, they push on the cross-shafts which cause the spider gears to push on the side gears... the same way an open diff works.
However, because of that power path, the torque through the unit controls how hard the #9 components are squeezing the clutch packs. Since the normal force on the clutch pack is proportional to the torque applied to the unit, the "lockup torque" of the unit is a fixed fraction of the torque being put through the unit.
If you all the coefficients of friction, you can calculate what this fraction is.
But a rating like "max lockup torque of 500 ftlbs" can not be applied because that torque varies with how much torque is applied to the unit.

A Torsen is a bit different in that the max torque in can bias to the wheel with more grip is a fixed ratio times the torque that the wheel with less grip can deal with.
Yes, it's measured vi a bias. quaife has good tech on this.

Anyone with an engineering back ground able to more explain how to measure the ramping lock up? And also the difference between sprung and unsprung?
__________________
OBD1 M54/M52TU swap as a M50b25
Z4 non powered steering rack fits e30


Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine
Wanganstyle is offline   Reply With Quote
Old 05-14-2012, 12:43 AM   #29
durtyE30
Mod Crazy
 
durtyE30's Avatar
 
Join Date: Aug 2010
Location: Boca Raton, FL
Posts: 707
You have an amazing mind I wish to pick in the future, when I've got more money to rebuild my differential...until then, keep being awesome.
durtyE30 is offline   Reply With Quote
Old 05-30-2012, 01:28 PM   #30
th3blue
Advanced Member
 
Join Date: May 2009
Location: rochester, ny
Posts: 114
I just came back from watkins glen and running pilot sport cups my 140k 3.94 LSD was failing hard in tighter turns.

what's the best value home rebuilding that will refresh and upgrade while keeping costs down?

It's basically a drive once a week for fun + track day car.
__________________
1997 BMW 328ic 5spd sport Moreagrun Metallic
1989 BMW 325is 5spd with a M50 swap
2006 Audi A3 6spd DSG sport with APR stg 2
th3blue is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 06:49 AM.


Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright 2004 - 2020 R3VLimited LLC