Help! Steering vibrations and understeer

[mrx928]

I'm running Fk silverline plus on my mk6 wagon. Decided to pull the helpers off today and brought the front down to 23 3/4 ftg (rears are at 24 ftg). I also set my dampers to 3/4 firm front and 1/2 firm rear.

Took the car out for a test run and noticed quite a bit of understeer and a very weird steering wheel vibration that comes with the understeer. Adjusted dampening and no changes. Jacked the car up and put it to 24 1/4 ftg up front and all understeer gone (relatively speaking for a wagon) and no more steering vibration thru hard cornering.

Can't figure out what might be causing this. Anyone else experience something similar going below 24ftg without helpers?

 

[RacingManiac]

Does the vibration accompanied by copious amount of tire noise?

 

[mrx928]

Does the vibration accompanied by copious amount of tire noise?

Yep. As amount of understeer increased so does amount of tire noise. At the raised height it's mainly noise during understeer. At the lower height it's noise and vibration. Almost feels like the tires is "skipping" across the ground.

 

[RacingManiac]

It sounds like its just terminal understeer noise that normal tires make. The vibration is just the effect of the tires being pushed.

The fact that you adjusted damper and brought no change suggests to me you've bottomed the front suspension out, effectively bringing your front stiffness to max and that's not very good for a FWD car...

 

[mrx928]

It sounds like its just terminal understeer noise that normal tires make. The vibration is just the effect of the tires being pushed.

The fact that you adjusted damper and brought no change suggests to me you've bottomed the front suspension out, effectively bringing your front stiffness to max and that's not very good for a FWD car...

Thanks! This is very helpful. Going to raise it back up to 24 ftg and just keep it there. Was hoping that as bad as I knew performance would be in the 23's it wouldn't be as disappointing as this. I can deal with a bit of bounciness but this amount of understeer leaves the car undriveable.

 

[mrx928]

Update, raised it up to 24ftg which evened out my front and rear height. Understeer and vibrations seems to have improved but still definitely there.

Inspected my endlinks and it looks like the rubber bushings are torn. Tested to see if there was movement between the strut, endlink and swaybar but all seems to be tight.

Can someone confirm if an endlink bushing is on its way out would it create the vibrations i'm experiencing?

 

[RacingManiac]

Videos might help to see or hear what might be happening?