Posi Rear End???

Ford's version of the Posi (A GM name) is called Traction-Lok. An open rearend (non posi) delivers power to only one wheel at a time, supposedly the wheel with the most grip. In practice I've found that it delivers the power to the wheel with the least amount of grip.

The Traction-Lok (or Posi) will deliver power to both wheels regardless of available grip.

A wet nitrous system has a FMU (fuel management unit) that adds fuel as nitrous is used.

A dry nitrous system depends on the car's computer to be able to read that there is extra oxygen (from the NO2) in the fuel/air mixture entering the engine and lets the computer add the extra fuel needed.

Dry systems are fine for low power levels (under 100) while I would prefer a wet system above that.

Also to add on to Maryland's post... All Mustangs with the 5.0L motor came out of the factory with the Trac-loc rear end in them. If your car is experiencing 1 wheel peel than all you would need is to have your current rear end rebuilt with new parts.

The difference between Open and "Posi" is quite noticeable when you first drive the car after a rebuild.

youn dont need new gears either

Your car (if it's an 89) already has a Traction-Lok rearend -- you already have posi. If it's not working (symptom is just the right rear tire spinning when you smoke 'em), a shop can rebuild the traclok unit without removing the differential.

A wet nitrous system adds the additional fuel required with separate injectors nozzles for fuel. These typically are installed somewhere downstream of the throttle body in the intake manifold. A dry nitrous system senses when the nitrous is activated, and typically elevates the system fuel pressure so that the additional fuel required is supplied by the car's existing injectors.

With either system you need to be certain you have enough fuel pump to meet the cars needs for fuel. Running lean with nitrous usually results in catastrophic failures which are neither pretty or cheap to repair. Depending on how big of a shot you're running, with a dry system, you may need to switch to larger injectors to have the capacity to provide enough fuel for the extra oxygen provided by the nitrous. Of course, with that larger injector comes the need for a recalibration of the maf or ecu to accomodate the larger injectors.

The downside of a wet system is puddling of fuel in the intake, and the possibility of an intake explosion as you now have fuel mixed with air in the plenum. The upside is you usually don't have to worry about whether your stock injectors have enough capacity to provide the additional fuel needed.

The downside of a dry system is being sure you have enough injector capacity to supply the additional fuel, and being sure your calibration for larger injectors (if you must do that) is good so that drivability/efficiency are preserved when you're NOT using the nitrous. The upside is better mixing/vaporization of the fuel that's added since it's coming in via the injector, and no chance of puddling of fuel as could occur with a wet system.

Insurance company won't cover repairs of that nature, they are considered wear and tear items.

get an Eaton posi

ford Tracloc aint that great it will pull both wheels to a point.they r ment to pull "posi" but wont always b/c it is a limted slip and uses clutchpacks. i work on them all the time. they do have to remove the diff to replace the clutch packs which are more than likely burnt up in your rear end. a way to get it to pull both wheels more often is double packing the clutch packs (they dont last as long though). ur better off w/ goin w/ a detroit locker( a heck of alot stronger). running a full locker has its cons which r when ever ur sending power to the differential (accelerating no mater what speed, how much throttle ,etc.) it will send power to both wheels(like a spool). driving on ice/snow/wet roads makes the car wanna fishtail as soon as you break traction. so when ever u take a corner ur gonna hear the inside tire chirp unless u can get the air pressure down enough to get the tire itself to flex. ive driving countless fords w/ the trac loc rear end i aint impressed its just a factory limited slip (factory stuff sux in my opinion). the Eaton Posi uses clutch packs and is a limited slip. i come from an offroad background where lockers and spools are kings. just my .02

get an auburn pro

meh, they're not rebuildable