car ran smooth before coil over install. now we get a vibration at 80 mph. smooth at 70 mph. we have not done an alignment yet or balanced the wheels. anyone have any thoughts? thanx in advance

 

It's possible your higher spring rates and stiffer shocks are just transferring the original vibration you had that the older softer set-up cancelled out. You may need wheel re-balancing and to check the tires for uneven wear. Jack your vehicle up and just spin the tires. A good tire will have no humps or ripples. Also check the inner part of the tire as sports cars with negative camber will really wear the inner tread really fast.

 

The tires were just balanced maybe 2 months ago but it still could be that. I am only running stock camber in the back (which is actually quite a bit) and barely any camber in the front. (just enough to clear tires/fenders). I am thinking it may just be how coilovers are on the freeway but I don't know for sure because I have never ridden in another car with coils.

 

Just know that vibrations don't come from the shocks / coilovers. Something is out of balance somewhere on your vehicle. Bad U-joints in the drive shaft can also cause vibration. The stick on wheel balancing weights fall off all the time.

 

K Sport Kontrol Pro. 7k f and 6k r is what it says online. And yeah they are dampening adjustable. I just have the dampening set in the middle all the way around.

 

Just to be save make sure all the bolts are tighten.