How does Posi-traction work?

How does Posi-traction work. I know it get the wheels on a axle to spin at the same rat of speed no matter the pavement. Got this off of

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Can anybody break this down a bit in terms of what is necessary to do this, a Differential??? And also who has it and do they like it??? Someone told me that on my car there is a place to put a pin though the axle and that would do it. Does this sound reasonable???

[wezeles]

did you go through the whole list of types of differential's and the diagrams to see how they work?

http://auto.howstuffworks.com/differential1.htm

i have posi in my car.. most rwd cars run the open diff style "aka" one wheel wonder...lol pretty much one wheel spins and thats it... it can transfer power from one wheel to the next in some cases but still only uses one wheel to drive the car... where as in a posi diff your spinning both wheels all the time and they only change the amount of power when needed... the only downside to adding posi is harsher weather in rain,snow,ice... your gonna tend to spin more with posi because you have both wheels spinning and if you hit a patch of ice with one tire the other tire is just going to push you into a spin... where in open diff styles the tire on the ice will just spin and you will pretty much keep on rolling ... posi does it too, but not as much..posi is more intended for 4x4 where you need offroad traction... pretty much garantees you will get traction but in michigan in rain and snow..lol sometimes traction is bad...

i love having the posi leaving 2 black lines instead of one... but when it does rain out i have to be careful when driving... but if it is just a nice weather car i would say do it specially on something like a 3.8 your not running gobs of power where a tap of the gas in the rain will make it hard to drive.. while your at it get some larger hears... make it a little quicker

[wezeles]

and if you wanna get really crazy you could go with a locker diff...which sucks for turning but for track cars works nice... and really beefed 4x4's pretty much both wheels spin all the time no matter what when the locker is engaged.

[phoenix_rising]

Did you mean get some new gears??? What kind? I noticed that on the way home when Nick was doing burnouts only one of his tires was moving. Reminded me of my Mom's '86 Caprice. I don't like that. I think I will pursue a posi set up. What would the locking differential do to turning capability? Thanks

[wezeles]

best bet for an easy swap is just get a full diff/gear set... get like posi gears with 3.42's or a little higher... the easiest swap would be to find a new axel at the junkyard or someones old stock one they beefed up a bit... swapping out a diff isnt hard... but for a first timer at it, it will be more than a headace...

[JoeliusZ28]

Someone told me that on my car there is a place to put a pin though the axle and that would do it. Does this sound reasonable???

lmao, hell no. that would be even more ghetto than a ghetto posi. and btw a ghetto posi is welding the spider gears together so there is no slip whatsoever. the latter is a common practice in derby cars, since they will never really see turning on pavement again, and the inner wheel will just slip on dirt.

[wezeles]

well the person that told him that was probably thinking of the really old axel setups where the only difference in them was a pin through the diff that converted it from open diff to a posi... but a cheep version of posi.. ghetto rigging has its place in derbys,dirt tracks, and the ocassional track only car that will never see a turn more than onto a tralior most its life... but dont do it to your summer driver... but if you do do it let me know i wanna drive behind you and laugh as you go around corners...lol

[JoeliusZ28]

if you did that to a daily driver, it would only be a matter of days before it snapped and a complete axle shaft (with wheel still attached) would come flying out the rear end while going around a corner

[93formulalt1]

I'm thinking that you don't really need posi with a 3.8, it's just more work. Sell your car and buy a V8!!! I'm only upgrading to some 3.73 gears, and then I'm leaving it alone until I swap in my 4.3 or the 355 in the garage. . .

[97rs4life]

I bought a z28 rear end and swapped it into my car. Went from 3.08 open diff to the z28s posi/3.42 rear end. It was a great swap, could feel a difference and leaves nice burnouts.

First check your car for a GU# code on the drivers door, and let us know what number you have. That will tell us what gears you currently have.

[phoenix_rising]

Ok sounds like I need to make a trip to visit my ride.

[97rs4life]

also check for Y87 while your at it

[1bad83ta]

So Ben do you know how a posi works now?

[wasjo6431]

i had a 3.23 posi rear axle before in my firebird. then i blew it. (big time blew it lol) then put in a 3.08 open.
then i tossed in a 3.42 posi. the v8 loves the new gears. it hated the 3.08 its to weak. taller gears are better..... but dont go over 3.73 on a v6 unless you got other things done to it.
i plan on going over 4.xx when i do my 9 inch rear axle. after this one blows and i throw in anohter one. and it blows.

[ZeeVert]

Since we're talking about diffs, I thought I'd share something else about diffs. You may not have realized this, but when you're going straight, the bevel gears (side and pinion) don't actually spin. They only spin when turning (or during a one wheel burn-out).

And since most driving is relatively straight, and the bevel gears aren't spinning, they don't really have any bearings. As a matter of fact, most of the newer bevel gears have as-forged gear teeth, which aren't very precise. Diffs aren't designed to do a lot of turning.

There is another way to "spin" your diff. Putting on tires with different diameters on the same axle will also spin the diff. So, if that space saver spare isn't the same diameter as the other tire, you're going to really give your diff a work-out.