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-   -   posi (limited slip) vs. open differential (

william27103 01-16-2006 09:59 PM

posi (limited slip) vs. open differential
what are the pros and cons of limited slip posi's, and the pros and cons of open differentials?

facts and opinions welcome

malc 01-17-2006 01:27 AM

Here´s a good explanation of how diffs work.

curtis73 01-17-2006 02:11 AM

Depending on what kind of limited slip, the only real drawback is cost. The Auburn-style cone limited slip like GM used for many years is nice, but not rebuildable. The Eaton-style clutch posi is rebuildable and offers a touch better adjustable torque bias. The Gov-lock is basically a clutch-style posi that is open until wheel slip is detected, then it applies pressure to the clutches and it operates much like an Eaton posi.

There are countless kinds, so I won't go into them all, so it might help if you just tell us what the application is. That way we can tell you some pros and cons of the few posi's that would be effective in your application.

Depending on the type of posi there are huge benefits and some drawbacks, but an open differential's only benefit (in my opinion) is cost. If you're willing to pay for the right posi, you still get the transparent operation like an open diff, but when you need the traction its there at both wheels.

jimfulco 01-17-2006 09:09 PM

A posi takes a little more finesse to drive on wet streets. With both wheels under power, it's easier to lose traction going around a corner, but you'll learn to go easy on the throttle real quick. A little practice in an empty parking lot goes a long way.

william27103 01-18-2006 09:11 PM

the application is a 425hp 1980 camaro with a 700r4 trans that will serve as an "almost" daily driver (rain or shine) but it will also see a few runs at the strip, but way more street time than strip time, probably like 93% street and 7% strip and other

Blazin72 01-18-2006 09:23 PM

With that kind of power you're gonna want a limited slip diff. They really arent that bad in the rain you just have to be careful when you're hard on the throttle around corners. I have a locker in my Blazer and I've just about turned it around a few times. But...I was kinda trying to. :D

Besides, open diff burnouts just arent as cool :thumbup:

william27103 01-18-2006 09:28 PM

ha ha, yeah, the good ole' "one tire fire" lmao

now the question is, build a rear with a new carrier and new gears cause i have an extra that i can build and still drive my car until i get it done

or steal the already posi out of the 79 trans am i have in the yard (which probably isn't a good idea cause we're fixing it up next, and it just isn't a trans am without a posi...)

xk8 01-19-2006 08:52 PM

Go with the Auburn Posi
Put the Auburn Posi in, and I just loved it until some (SOB !@#$%^&*) stole my 4x4 Chevy. I read about the different posi units all the time and would choose the Auburn again. The reason is price and performance, and if you wear it out or damage it Auburn will rebuild it for you. Go to there web site and read all about the Auburn Posi units available.

xntrik 01-22-2006 04:06 PM

avoid any kind of "locker"....

limited slips are best. I like the "gear" unit from Currie, etc.

joe350s10 01-22-2006 05:52 PM

When I first got my truck it had a posi rear in it. It was great for doing burnouts and showing off, but not very "streetable" whe it came to everyday driving. The slightest moisture on the roads and it was a beast to keep going straight.

And absolutely no going in the snow.

But, the pinion was shot and soon that rearend was I switched to a standard "one legger" out of an old impala rear I had lying around.

No more dual blackmarks off the line, but great in the rain and snow.

I wouldn't mind having limited slip, but what I have works nicely.

And I don't have to replace the rear tires as often :D

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