Still plugging away and checking on things, thanks for all the advice. My rims are all mixed up so trying to get it evened out and balanced, I have the slotted mags but a couple of them are slightly different on the back spacing so the offset was not even, so I put the pair that matches up best on the rear and the other 2 rims that match up closely on the front. I guess I may just sell these off individually or something down the line, because not a single one of them matches another perfectly although they look alike. Now, the differential strap (arrestor strap?), is that supposed to be loose with the car jacked up or what type of tension should it have because its fairly loose and maybe thats throwing off my suspension. I remember replacing it, heck maybe I put one on thats too large.

That strap is pretty loose. It's really just a fail safe thing in case the rubber mount fails. You should get a matching set of rims. That could be your problem. Are you a Z Car Club of Colorado member?

Edited February 21, 201312 yr by 30 Ounce

Specify which mounts you replaced. I'm curious.

My rims are all mixed up so trying to get it evened out and balanced, I have the slotted mags but a couple of them are slightly different on the back spacing so the offset was not even, so I put the pair that matches up best on the rear and the other 2 rims that match up closely on the front.

Mis-matched wheels and tires on an axle will cause the behavior you describe. The issue has nothing to do with the differential mounting.

Mis-matched wheels and tires on an axle will cause the behavior you describe. The issue has nothing to do with the differential mounting.

Agreed, mistmatched wheels/tires are a big no-no...

True, especially on these cars! That would have been good info at the beginning of this thread.

Im curious, when did you notice rim or tire size differences? you stated having 215-60-R14's on 14" wheels.

You should get the rims sorted out before going any further. You dont mention the offset difference between the rims, but some can have 38mm and others 0 mm. That would muck the geomentry up a lot and cause the car to react like you are experiencing under throttle no-throttle conditions.

Even getting some spacer plates made to get them all even would be a good start. You can then test them to check if its better. I would start looking for a matched set for a perminent solution.

Chas

BTW... I'm guilty of the mis-matched wheels mistake - to the tune of $1,300 in my case.

Rear End Steering Under Power - Drivetrain - HybridZ

I need to take all 4 back off and measure each again. Thing is I knew I had 2 dif offsets, but was under impression Id be ok as long as kept them paired front to back. Been so cold last few days no desire to mess with it, warming up tomorrow. Im not sure how to measure exact offset of each rim, Ill snap some pictures and post tomorrow.

Measuring the offset is easy. You just need a straight edge and a tape measure. A straight edge can simply be a piece of wood long enough so sits on the rim and doesnt sit on tyre wall.

Just measure the back rim to the hub mount with the straight edge. Turn the wheel over and measure through the stud holes or centre cap the front side. If you have no difference, then you have zero offset. If the back figure is higher, then you have positive offset +.... Front side higher then you have a negative offset -.... Remember you have to divide the difference to get the offset value.

To give you an example:

My wheels 14"x6" have a back rim measurement of 170mm and front are 95mm. Offset is 170-95/2 = 37.5mm. Because the back is the larger number, its positive offset. They are actually +38mm.

Here is a thread with a good sketch showing how and what to measure.

http://www.classiczcars.com/forums/general-modification/47065-ideal-wheel-size-offset-if-running-zg-flares.html

Chas

Measuring the offset is easy. You just need a straight edge and a tape measure. A straight edge can simply be a piece of wood long enough so sits on the rim and doesnt sit on tyre wall.

Just measure the back rim to the hub mount with the straight edge. Turn the wheel over and measure through the stud holes or centre cap the front side. If you have no difference, then you have zero offset. If the back figure is higher, then you have positive offset +.... Front side higher then you have a negative offset -.... Remember you have to divide the difference to get the offset value.

To give you an example:

My wheels 14"x6" have a back rim measurement of 170mm and front are 95mm. Offset is 170-95/2 = 37.5mm. Because the back is the larger number, its positive offset. They are actually +38mm.

Here is a thread with a good sketch showing how and what to measure.

http://www.classiczcars.com/forums/general-modification/47065-ideal-wheel-size-offset-if-running-zg-flares.html

Chas

Something is drastically wrong in your method, especially if you're referring to the 5-slot mags in your avatar.

(1) Measure rim width (measure it, don't use the rated width)

(2) Divide by 2 to find wheel centerline

(3) Measure from the back face of the wheel to the hub mounting surface (backspacing)

(4) Subtract (3) from (2)

And you're done.