sly fox

Calling all coilover owners.

When i last fitted my coilovers, which are off the car at the moment, i used to get a lot of oscillation when the vehicle was crusing and under braking.

Has anyone else encounted this and / or knows how to cure the problem??

sly

P.S any one else out the with hks hyper-d's fitted on the scooby?

ex-webby

Hi Sly

Could you describe the oscillation. Is it the suspension oscillating and the car moving up and down with it, or the entire car being banged about up and down?

I'll assume that it's the suspension oscillating.

Thie basically means that the car is under damped, or over sprung. If you have adjustable dampers, wind them up a few clicks until the oscillation stops.. for speed, wind them to full and see if the oscillation has gone, then wind them back 50%, then forward or back as required, etc - repeat until you're bored.

If not, you might need softer springs, or firmer dampers.

If it is not the actual suspension oscilating, then there are a number of other possibilities, including too heavy wheels / brakes, too much bump damping, too heavy spring, etc.

All the best

Simon

Kippax

si, thats bang on. sounds underdamped to me too.

ozzy

I've noticed this feeling on certain road surfaces. Is this to do with harmonics. As soon as the surface changes to a nice fresh peice of tarmac the oscillating stops.

Not saying it's your problem, it's just always puzzled me.

Stefan

Kippax

ozzy, every car has a natural frequency. if its excited at that frequency, it oscillates at maximum amplitude for a given input. it probably is underdamped if thats the case. the STi 5 used to bounce with standard suspension and people would complain the suspension was to hard. it wasnt too hard, it was underdamped. so you can either increase the damping or reduce the spring rate (eibachs).

ozzy

I have Eibachs already on my std dampers (MY99 RB5). Have solid front/rear droplinks and a larger ARB.

Noticed it before drop-links and ARB. Had to the Eibachs too long to remember what it was like with full OE suspension.

Thanks,

Stefan

sly fox

very useful answers.

I think my original springs where over sprung as they where 510lb rated springs.

I'm going to try something a little bit less, say 275f / 225r and see what results that has.

cheers

sly