I just did a complete restoration on my 87 Iroc, I installed a NEW suspension all around, New KYB GR-2, swaybars, wonder bar, A-arms, Control arms, Panhard bar, torque arm, end links, and EVERY bushing. My problem is the REAR is springy and sags a bit and the front seems the correct stiffness. Why is the rear soo soft? It almost seems like the BRAND NEW shocks in the rear are bad Is there something I am over looking?, Is this normal with the GR-2s? ANY HELP would be GREAT! THANKS.

 

You don't mention replacing springs, which have more to do with sag than shocks.

JamesC

 

I swapped a set of 91 V8 springs with my 87 ones because I was afraid of that. The 91 srings I had powder coated, Thats horrible to just chuck them if that is the case. I should have kept the originals.

 

I suspect that the IROC springs were far stiffer.

JamesC

 

Springs are funny, original ones can last near forever if the shocks are kept in good shape. Them 91s could of been on a car with blown shocks for to long.

 

You said '91 V8 springs, but what model? That could influence the spring rates Ex: WS6, FE1, etc.

 

I think that may be the case, I have decided to drop her. I ordered a set of AG lowering springs (1.6 rear, 1.4 front). Is there any other mods I need to do when I install the springs? Or will they go right in? THANKS!

 

The springs will go right in, but dropping that much may require an adjustable panhard rod to recenter the rear end. I used an Eibach ProKit (only 1" drop), and I used an adjustable panhard to recenter my rear end.

Oh - and don't expect to actually see the car drop 1.6 in back there - the new 'lowering springs' will actually be longer (ie taller) than the old sagging OEM springs when the weight is set back down on them.