- Jan 9, 2016
- 1996 Collector Edition LT4 Z51 coupe (red interior
I'm looking here for helpful comments from someone who has experience driving a well-maintained (ideally '96) Z51-equipped car AND at least one other late C4 with standard suspension. I bought my '96 Z51 LT4 CE last summer with 44,000 miles on it. Showroom-looking condition, but with a vibration kicking in at around 70 mph. Thought it was the crappy generic cracked tires and aftermarket wheels, so these were replaced (now on Continental DW Extreme Contacts). The vibration didn't go away, turned out the main driveshaft had a strange scoring on it, and was possibly twisted but otherwise unbalanced, and the U-joints were pretty stiff, so I had it replaced with a custom balanced driveshaft. There's still some vibration at highway speeds, and it's making me want to postpone doing track days until a solution is found. Both my regular mechanic for over 25 years (who also works on several other C4's), and our local Corvette specialist garage, have test-driven and gone over the car looking at wheel/tire roundness and balance (balanced twice), wheel bearings, suspension joints, all of the usual indicators for vibration. I've also had a four-wheel alignment done at a local race-prep shop. Am I chasing nothing at this point? Is the Z51 suspension simply more sensitive to road surface irregularities at higher speeds? I have owned other sports cars, from Lotus Seven to Jaguar XKE, and would expect this Corvette to ride a bit more smoothly, more toward the Jag end, but is this what I get with Z51? I love this car, my first Corvette, but I'd enjoy it more if I could relax about the vibration!