How does a posi differential work?
Thread Starter
Race Director
Joined: May 2001
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How does a posi differential work?
I was talking with a friend the other day and we came to the terrible conclusion that neither one of us really knows how the differential works. I know the ring and pinion, but how does that work with actually turning the axle. How is it attached etc. How does it allow for tires to sping at different speeds?
I know in a non posi rear end if you jack it up and spin one tire, the other spins the other way. What makes it do that? How does the posi unit stop that, I know it has clutches and such, but I really don't know how it works.
Any info would be great, some pictures would be better. I just don't have access to a healthy posi and non posi differential to look at and see if I can figure it out.
I'm trying to learn as much as possible about every part of the car. I know a LITTLE about most everything else on the car, this I don't know ANYTHING about and I need to learn.
:cheers:
I know in a non posi rear end if you jack it up and spin one tire, the other spins the other way. What makes it do that? How does the posi unit stop that, I know it has clutches and such, but I really don't know how it works.
Any info would be great, some pictures would be better. I just don't have access to a healthy posi and non posi differential to look at and see if I can figure it out.
I'm trying to learn as much as possible about every part of the car. I know a LITTLE about most everything else on the car, this I don't know ANYTHING about and I need to learn.
:cheers:
Safety Car
Joined: Feb 1999
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From: Mexico Beach FL
Re: How does a posi differential work? (Nathan Plemons)
The positraction clutches have static spring pressure on them to attempt to keep the "side" gears rotating at the same speed -- this is the force you can check with a torque wrench. When a "load" is put on the differential, that load (through the angle of the side and spider gears -- some manuals call the spider gears pinion gears, but don't confuse them with the pinion shaft of the "ring and pinion") causes dynamic pressure on the side gears proportional to the load to be applied to the posi clutches. This increases the amount of force needed to break the clutches loose and allow one wheel to spin faster than the other.
Tom Piper
[Modified by Tom Piper, 1:08 PM 2/26/2002]
Tom Piper
[Modified by Tom Piper, 1:08 PM 2/26/2002]
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From: The Top of Utah
Re: How does a posi differential work? (Nathan Plemons)
I don't know where to start. I don't have the capability to post pictures, and I believe that they are necessary to do the job properly. Do you have a picture of a non- posi diff you can post? I bet that a lot of forum members would be interested in this. Probably quite a few others could explain it, too. Like I said, I don't know where to start.
Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: How does a posi differential work? (Tom Piper)
Correct, Tom. But unless I misunderstood the question, I think Nathan needs to have the operation of the differential, explained, first.
Thread Starter
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Re: How does a posi differential work? (CFI-EFI)
Believe it or not I just searched on "How a Differential works" and I found this site http://www.howstuffworks.com
Some of the graphics are a little cheap, but it does the job. Some better pictures might do a little better justice to it. I'm afraid I don't have any good pictures myself.
Some of the graphics are a little cheap, but it does the job. Some better pictures might do a little better justice to it. I'm afraid I don't have any good pictures myself.
Team Owner
Joined: Apr 2001
Posts: 22,267
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From: Dallas TX
Re: How does a posi differential work? (Nathan Plemons)
Believe it or not I just searched on "How a Differential works" and I found this site http://www.howstuffworks.com
Some of the graphics are a little cheap, but it does the job. Some better pictures might do a little better justice to it. I'm afraid I don't have any good pictures myself.
Some of the graphics are a little cheap, but it does the job. Some better pictures might do a little better justice to it. I'm afraid I don't have any good pictures myself.
