5th Coil Spring...

[kevpow]

How soft is too soft and why? What are the pros and cons of soft versus stiff?

[hpmaster]

I go by total movement more than spring weight, I shoot for 3.5 to 4 inches on a given surface, not saying it's right or wrong JMHO

[Ghopper]

On the same line as HP was mentioning: the force through the spring is the same no matter the rate, but travel does change. The spring travel is your control of pinion movement between braking and under throttle.

Ghopper

[MasterSbilt_Racer]

How soft is too soft and why? What are the pros and cons of soft versus stiff?

Too soft is when a stiffer one makes the car faster. Honestly, that is the best answer.

[Matt49]

The 5th coil is a torque absorber. Asking what size spring is appropriate is to ask what amount of torque is appropriate to absorb. That depends on several factors included but not limited to: track conditions, tires, driver input to gas pedal, and engine output.
There are also other things to consider here such as the j-bar rake change that comes with changes in pinion angle.
If you take all these things into consideration you quickly find that there is no simple answer.
Chassis manufacturers and other "experts" will give you guidelines but that doesn't mean that your situation doesn't warrant experimentation outside those boundaries.
Travel is a good indication of how much torque is being absorbed but that information by itself doesn't tell you much unless you've reverse engineered all of these factors into what travel is telling you.
Also remember that 4 inches of travel at 31 inches and 4 inches of travel at 37 inches have very different effects on pinion angle.

[7uptruckracer]

I dunno why I never though of it till now but with a crate won't you run a stiffer spring because it has less torque to absorb? We wouldn't still wanna shoot for four inches would we? What have yall found here? Same spring just shorter lift arm or keep the distance but not run as soft? Its not like the crate will buzz the tires as easy from to short of a lift arm.

[phenom08]

test, test, test, some drivers prefer a stiff spring others soft. there's really no wrong answer

[keeks]

I would say that the less torque you have/slick track you would want to run a softer spring.

[spray004]

My torque arm has about 4 or 5 holes for the shock to mount. I have mine mounted mounted in the middle hole which is roughly 90 degrees to the torque arm. Should the 5th coil always be mounted 90 degrees and the other holes used if I want to move the 5th coil front or rearwards for more leverage?

[Bubstr]

Why are turds tapered? Answer, So your but don't slam shut. That may sound silly, but that 5th coil is the taper on your torque. It don't reduce or increase overall torque, it just modifies the transition.

There are a lot of things that determine what you need from it, from how much torque your engine makes at a certain RPM, to what gear you run, to how light footed the driver is, how much traction there is, to how much corner speed you carry. I believe travel is the best guide, but lap times and drivablility rule.