3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

Do all FD's come with LSD rear ends?

Thread Tools
 
Search this Thread
 
Old 12-15-02, 01:31 PM
  #1  
Rotary Enthusiast

Thread Starter
iTrader: (6)
 
lerch32's Avatar
 
Join Date: Aug 2001
Location: Fredericksburg, VA
Posts: 824
Likes: 0
Received 0 Likes on 0 Posts
Do all FD's come with LSD rear ends?

I have been told that they do. I know for a fact that I do not have one, and will be needing one for the upcoming season. I just want to know once and for all if they do or don't.
Old 12-15-02, 01:39 PM
  #2  
Full Member

 
Join Date: Nov 2002
Location: Houston Texas
Posts: 167
Likes: 0
Received 0 Likes on 0 Posts
Arrow What????

How do you know that yours is not a Limited Slip Differential?? Could just be that your clutch disks are all worn out and need replacing. Did you open it up and check the setup??

Just saying this since it would be a considerable design difference in the event that it didn't have a LSD (sounds too much like drugs). I wasn't even aware that the rear end was offered without LSD functionality.
Old 12-15-02, 02:39 PM
  #3  
DK
40k worth of fail

iTrader: (5)
 
DK's Avatar
 
Join Date: Mar 2001
Location: Hermosa Beach, CA
Posts: 1,312
Likes: 0
Received 0 Likes on 0 Posts
Every single one of them came with LSD.
Old 12-15-02, 04:09 PM
  #4  
Full Member

 
jumprdude's Avatar
 
Join Date: Mar 2001
Location: San Jose, CA
Posts: 75
Likes: 0
Received 0 Likes on 0 Posts
All FDs came with Torsen LSD, as such there are no clutch disks to wear out, and special "friction modifiers" need not be used in the differential oil.
Old 12-15-02, 05:59 PM
  #5  
Do it right, do it once

iTrader: (30)
 
turbojeff's Avatar
 
Join Date: Apr 2001
Location: Eugene, OR, usa
Posts: 4,830
Likes: 0
Received 12 Likes on 8 Posts
jumprdude is right. ALL FDs have LSD and there aren't any clutch discs to wear out.

Lerch32, you can't know for a fact that you don't have an LSD. If you have a FD it has a torsen limited slip.

Jeff
Old 12-15-02, 06:07 PM
  #6  
Full Member

 
eurautodave's Avatar
 
Join Date: Nov 2001
Location: cincinnati
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
you guys are right about the fds having torsen lsd but i think it would be nice to point out that the reason lerch doesn't think his car has one is because they don't work like a typical lsd. a torsen, torque sensing differential, works like an open diff until a wheel starts to spin. then it works like a limited slip, feeding torque to the wheel that isn't spinning...kinda like the best of both worlds, but if your looking for a conventional locked diff you won't find one in any fd3s.
Old 12-15-02, 07:16 PM
  #7  
Full Member

 
Join Date: Nov 2002
Location: Houston Texas
Posts: 167
Likes: 0
Received 0 Likes on 0 Posts
Arrow Hate to burst your bubble!!

as such there are no clutch disks to wear out
Actually there are, maby my lingo is a little off. In the LSD you have friction plates on each side, thats how you get the LSD action. When they start to wear out, you get problems like this.

One of the biggest problems that you will have is improper alignment of the ring gear with respect to the pinion. If this happens, you will get uneven wear of the friction plates in the LSD and the car will eventually start to favor one side under hard load. You will see this if you have an inexperienced installation of a new pinion or ring gear, even a replacement of the internal bearings or oil seals. If they didn't check the placement of the adjustment shims or they put the wrong bearings on the wrong side this will happen eventually because the ring and pinion are not aligned perfectly (and they must be perfect!!).

Consider yourself lucky if this is the problem. Worst cases of this I have seen the pinion gear head break off in the rear diff and sometimes explode out the side of the case like a loose projectile.

Reinstall should be done by a qualified tech so they replace all the proper bolts, bearings, oil seals and shim it correctly. You might have to get your ring and pinion replaced if they wern't aligned correctly (basically they are worn to each other at a bad angle).

In all, might be cheaper to find a junk yard rear end and do a swap if your LSD is beyond rebuild and your ring and pinon are also worn incorrectly.

Here is an example of an aftermarket LSD -

LSD RX7Trix

Good luck with it!!

Last edited by shred; 12-15-02 at 07:26 PM.
Old 12-15-02, 07:25 PM
  #8  
Full Member

 
jumprdude's Avatar
 
Join Date: Mar 2001
Location: San Jose, CA
Posts: 75
Likes: 0
Received 0 Likes on 0 Posts
Not true at all!

Originally posted by shred


Actually there are, maby my lingo is a little off. In the LSD you have friction plates on each side, thats how you get the LSD action. When they start to wear out, you get problems like this.

Torsen LSDs do not have a friction plate! The friction necessary for operation comes from the natural friction in the movement of the worm gears within the LSD. These gears do not wear out in the course of normal operation.

Here is a link to describe the operation of the Torsen LSD:
Torsen LSDs

The KAAZ LSD you posted is not a Torsen LSD.

Last edited by jumprdude; 12-15-02 at 07:41 PM.
Old 12-15-02, 07:41 PM
  #9  
Full Member

 
Join Date: Nov 2002
Location: Houston Texas
Posts: 167
Likes: 0
Received 0 Likes on 0 Posts
Arrow I stand corrected!!

Learn something new every day. So I will eat my words with this quote from the page that was listed by jumperdude-

It's also important to note that while this design relies on the
friction characteristics of the gear teeth to control its behavior, it
*doesn't* use friction to transfer power (like a Clutch Plate LSD).
This design doesn't have any more wear than a conventional differential.
Thanks jumperdude and turbojeff for setting me straight on this one. Talk about some weird stuff. Car just never ceases to amaze me at all the engineering that went into its constuction.
Old 12-15-02, 08:55 PM
  #10  
Rotary Enthusiast

 
KevinK2's Avatar
 
Join Date: Dec 2001
Location: Delaware
Posts: 1,209
Received 5 Likes on 5 Posts
The torsen lock-up is based on torque and internal rubbing friction, as noted. For me, too much lock occured for wet weather driving, with just redline 75w90 gear oil, which includes the friction modifier for lsds. I added an extra mini-bottle of redline modifier (slippery stuff), for a little less lock ... worked for me.

I change annually when doing 5+ road track events. goes in typical tan, comes out black ... lots of friction heat.
Old 12-16-02, 10:01 AM
  #11  
Rotary Enthusiast

Thread Starter
iTrader: (6)
 
lerch32's Avatar
 
Join Date: Aug 2001
Location: Fredericksburg, VA
Posts: 824
Likes: 0
Received 0 Likes on 0 Posts
Thank for all the great info guys!!!
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Th0m4s
Build Threads
25
02-26-19 02:04 AM
coltboostin
Rotary Drag Racing
0
08-20-15 11:37 PM



Quick Reply: Do all FD's come with LSD rear ends?



All times are GMT -5. The time now is 06:19 AM.