coilover and helper springs? yes or no?

[urbandork]

I was wondering what the down and upside of helper springs are other then just ride comfort? what are the pluses and minuses of having helperspings on a coil over set up?

[Jeeves]

Seems like they'd keep springs from sagging over time, but I've never heard of anyone running 'em.

[bgrieger]

As you suggest, helper springs make overly stiff springs tolerable for off track use, or multi surface use such as an asphalt rally. The idea is bascially to create a dual linear rate spring setup, without going to a progressive rate spring (which are less predictable as when they start to get stiffer).

For 1 or so inches of travel (depending on the helper chosen), the helper softly absorbs the initial movement, making a fairly smooth ride on level roads, and allows you to run less stiffness in the dampers while not getting all bouncy. When the car is pushed harder into corners, or over really rough spots, the helper spring binds and all the load is carried by the much stiffer main spring.

This arrangement is really useful for a dual purpose car as you compromise less on the at limit tuning for a car that has to do more than one thing in life. You can run the stiff main springs and high rate dampers to allow you to pickup quicker lap times and still not shatter teeth on the way to the track.

This setup is also useful for rally type events, where the asphalt may be very smooth, followed by some really rough spots. A really stiff linear spring would bounce like heck on the rough stuff, and be just right for the smooth portion. A soft spring compromises the smooth stuff, and is quite happy in the rough. Best of both worlds in many ways.

Downsides...if you turn the dampers down for smoothness, you may find it gets bouncy as it's too soft to control the main spring on harsher road surfaces. You will also find that if turned too high, the ride becomes harsh as the helpers move more easily than the dampers do. You might also get rebound issues after bumps where the car feels very light as the road falls away from the tire and the helper spring can't move the damper down fast enough to compensate. You literally catch air for short periods of time.

It's a compromise, but I've never heard anyone complain too much about them. HKS, Tein and others have them on various models.

[urbandork]

thanks a bunch. that was probably the only explination ive gotten from any forums so far.

i posted this in the celica section as i have 6th gen celica gt US with a 3rd gen 3sgte in it and my gr2/sportline isnt cutting it any longer and ive been looking into coilovers.

any more info is welcomed