DIY Posi Mod for the Camaro Differential

[RichsGreyGT]

To be honest, I haven't driven the car much recently. I took it around the neighborhood the other day and didnt really notice it much. When backing it out of the garage and making the turn down the driveway, I did notice it was loading up some. It is kinda jerky but not necessarily skidding the tire. This on the a 275/60/R15 drag radial though... more grib and soft sidewall. I'm sure it would still skid my street tires in gravel or rain. It's definitely too much preload resulting in a high torque bias. Driving it more may help as it wears. If I have it apart or build another one, I will reduce the preload somehow.

I have Nitto NT05R P285/45/18's on my rear. My car jerks hard in grocery store parking lots and various maneuvers under about 15mph.

I just added a couple more ounces of GM Friction modifier Saturday. I'm hoping it helps. I might leak some of the oil and empty the rest of the bottle in there soon if it doesn't start working on the plates.

I'm becoming confident the mechanic that installed my clutch kit set the preload to the max. its pretty bad.

oh well, I'll chase it with money and make it right.

[RichsGreyGT]

Thanks for the reply!

[RichsGreyGT]

Quick update...

Adding a couple more ounces of the GM friction modifier have improved the jerking on slow turning on concrete/asphalt. I originally just added the whole 3.3floz bottle after the rebuild. Apparently it wasn't enough.

I'd have to drain some fluid to get the rest of the second bottle in the pumpkin. I think I'll just deal with it on the ocassioanal jerkiness.

[Phil@PnP Tech]

Seems on par to my experience so far. I swapped on the street tires this weekend and it was pretty tame until I pulled into the garage on the slick concrete. It was then in full spool mode.

[RichsGreyGT]

I wholeheartedly agree. the symptoms are really dictated by the surface you are driving on. In supermarket parking lots with smooth asphalt, its binds/jerks/lurches pretty bad. On a typical two-lane road surface turning, its almost unnoticeable.

I guess thats the price I pay for a beefed up 3.45 pumpkin.

[GT Drew]

I found a similar kit through Camaro Central. They have a way to gauge the preload. With the spring and clutches installed in the posi case, the two haves will be held apart by the spring. The size of the gap determines the preload. (From the install instructions) "With feeler gauges or a dial caliper, measure the gap between the two cases. This measurement will set the preload spring tension on the clutch discs when the case halves are bolted back together. This is absolutely critical to the proper function of the spring pack. This measurement should be .125 with a tolerance of plus or minus .0625. If the measurement is not within tolerance, use the selective shims provided in the kit to obtain proper clearance. Add or remove shims as required and repeat steps 6 thru 9 until proper clearance is obtained. When proper clearance has been obtained, the clutch discs will have between 200 lbs. (.0625) and 400 lbs. (.1875) of force with 300 lbs. (.125) being optimal. "
When I set mine up I will aim closer to the 200 lbs range. For a laugh I will measure what the preload is with just the stock clutches, none added. We may find that just the spring alone is what most will want
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