Posi Trac rear end or not?

[drbb]

Some of you are using a posi trac rear end and others are not? For those of you who have one, would you do it again or would you change anything? I hear that there is a clunk that goes along with a posi trac rear end? Have any of you experienced both with and without? I have a 600 Hp engine, is hp alone enough of a reason to get posi trac or is it just necessary for a specific application? I am still trying to get all my ducks in a row before ordering. Thanks.

[RJacobsen]

Here’s my 2 cents worth, If you want 2 big black marks when you light up the tires, you will need a posi rear end.:3g: Without it you only get one black mark. The down side is that with 2 tires spinning you have less control, not a good thing if you plan on driving on ice.;)

[robbinsshkr]

If your gonna have 600 HP, I think you would regret not getting the posi. My personal opinion.....posi is a must have or you'll end up with a lot of useless HP off the line.
Eddie

[Jerry Cowing]

If you bought your Cobra to drive around like a grandmother, then you don't need a posi. Or you can buy a posi.

[Aggressor]

My experience with the Powerlock rear is that there are no clunks or notchiness associated with it. You really don't notice anything except the rather good hookup when launching.

-Geary

[spd4me]

I"ve got a posi and like the way it hooks up and goes. It does scare me once and awhile when I make a sharp turn a slow speed and you hear the clutches clink. I would suggest doing a web search on it and get some real tech info. I read an articele in racing book and they like the posi because if going around a corner and one tire hits oil or slick spot the other wheel will pull it trhough so both tire remain at same rpm. You do need to be sure you put the right type of oil in it (non synthetic) and posi track additive.
Bob

[Brent]

Without a posi the car is just a "sit and spin". Besides when you get on it and only 1 tire smokes it's embarrassing.

[robbinsshkr]

As you probably already know, the clunking or feeling the rearend feel a bit jerky at low speeds and tight turns is due to the posi unit disengaging as it has been designed to do. As you make a rather tight turn, the outside tire has a farther distance to travle than the inside tire that acts as more of a pivot point as it doesn;t make as many revolutions as the farter traveling out side tire.I'm not sure if the units from unique have clutch packs and springs like a GM type rearend or cogs that kinda mesh and seperate like a locker type found in the late 60's , early 70's ford mustangs, torino's, etc.[detroit locker, traction lock] plenty of those are still holding strong still today and they lived in 3800lb cars. Like it has been mentioned, these cars are much lighter, allowing for a lot less down force on the rear tires . from what i understand and have experienced, the jerky feeling you get in a tight turn is due to both rear tires trying to hold traction to the pavement, much less noticable in a light weight car.
If your really up for a challange, install a spool as Brent, myself and many others had to do in drag racing. trying to push a short wheelbased car in a turning position with hot sticky slicks that are 17'' wide and 33'' tall that do not disingage under any circumstances, will actually force you to push forward, backwards, forward again and so on until the turn has been completed. spools are great for their intended purpose, but would probably have a short life in a street application. If i have mis-spoken any of my facts, anyone please feel free to jump in and correct any of the above information.
Spending the money on a posi would be one of the better investments in your personal happiness, as well as resale later on down the road.
Thanks,
Eddie

[cal.cheesehead]

Hey have you lit up the streests of Boonville yet?

[eliminator]

Yes, by all means.....the real question is Why would you not, unless it's a grocery getter!!;)

[drbb]

Thanks for all the input, opinions and facts! So can someone explain what is the difference between limited slip and posi trac? This maybe a very uniformed question, sorry if it is.

[pbrown]

Thanks for all the input, opinions and facts! So can someone explain what is the difference between limited slip and posi trac? This maybe a very uniformed question, sorry if it is.

Posi trac IS limited slip. Positraction is General Motors name for their limited slip technology.

[robbinsshkr]

Hey have you lit up the streests of Boonville yet?

Hey Cheese,

Thanks for asking, but unfortunately the answer is no. I am VERY close and the warmer weather makes it hard not to cut corners to hurry and get it on the road. The things that I have left to complete are...
cockpit carpet [trunk is done]
door panels
install hood, trunk lid and doors
bleed brakes
seat belts
puller fan
once those things are done I'll be ready to run it on the jack stands for a bit allowing the trans and rearend to have some stress free "run-in" time.
Each week I tell myself "one more week and it will be done" I've said that several weeks now. I just keep coming across little things I want to change or do a little different. It should be complete in about "one more week" :D In all honesty, I hope to be on the road within 3 weeks.
Thanks,
Eddie

[Slither]

Hey Cheese,

:D In all honesty, I hope to be on the road within 3 weeks.
Thanks,
Eddie

Good luck, and keep us posted[thumb]...