KW V3 Spring Rates

[DB83]

For those interested, i've done a rough calculation of the spring rates on the KW V3 coilovers. Please don't take this as gospel as it may be off slightly but it should give you an idea of what they're running. Also, bear in mind this would be the theoretical maximum spring rates, but they would never reach it because it would hit the bump stops before then.

Front = 200 -> 700 lbs/inch (progressive)
Rear = 640 -> 770 lbs/inch (progressive)

Taking in to account the suspension travel i have in my car, i'm estimating:

Front 200 -> 350 lbs/inch
Rear 640 -> 690 lbs/inch

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[BmacIL]

How did you measure?

 

[DB83]

Its all calculated from wire thickness, number of coils, spring length, coil diameters, etc.
I'm sure there not 100% accurate, but i think they will be close. Since KW won't publish numbers this is the best i can come up with.
Next time i'm doing work on it i'm going to measure it more accurately with coil binding. That should give a much more accurate indication.

 

[BmacIL]

The rear springs for sure don't look to be progressive based on this picture:

The best way would be to measure applied load to a tire (or at hub face) and deflection of the spring. The motion ratios of the suspension are well understood, so it's pretty easy to back calculate the spring rate.

 

[SteveW]

The rear springs for sure don't look to be progressive based on this picture:

The best way would be to measure applied load to a tire (or at hub face) and deflection of the spring. The motion ratios of the suspension are well understood, so it's pretty easy to back calculate the spring rate.

Using the method your describe along with your spring calc sheet in the sticky i came up with 300 fr and 950 rear for the rates in my Roush V3 kit. The Roush is pretty much the same thing as KW. Although, rates could be different but i doubt it.

I ditched the springs for Hyperco 350 fr and 1440 rear. Wanted stiffer for autox.

 

[BmacIL]

Using the method your describe along with your spring calc sheet in the sticky i came up with 300 fr and 950 rear for the rates in my Roush V3 kit. The Roush is pretty much the same thing as KW. Although, rates could be different but i doubt it.

I ditched the springs for Hyperco 350 fr and 1440 rear. Wanted stiffer for autox.

That sounds a lot more like what I'd expect.

 

[2morrow]

Thread revival!

How do you guys like the V3 kit? Have any of you driven them on-track?
For those that have done a re-build, Was the process smooth with the manufacturer?

Trying to get some feedback on them. Thanks in advance.

-Todd

 

[SteveW]

Thread revival!

How do you guys like the V3 kit? Have any of you driven them on-track?
For those that have done a re-build, Was the process smooth with the manufacturer?

Trying to get some feedback on them. Thanks in advance.

-Todd

I did a little track driving with my set but mostly autocross. My focus is autocross competition and I don't feel like they are a competition grade set of shocks at this point. The out-of-the-box spring rates are too soft for that and the low-speed control just doesn't seem to be there either. For example, I could never put the power down really well no matter what I tried (shock settings, alignment, spring rates, etc.).

I am now using Vi-King Crusader AP front struts and shocks and these have totally flipped the script on the way I setup the car and drive it after a season with them. I just got a set of the new triple adj rear shocks but haven't tried them out yet. Just a few street miles so far.

 

[2morrow]

I did a little track driving with my set but mostly autocross. My focus is autocross competition and I don't feel like they are a competition grade set of shocks at this point. The out-of-the-box spring rates are too soft for that and the low-speed control just doesn't seem to be there either. For example, I could never put the power down really well no matter what I tried (shock settings, alignment, spring rates, etc.).

I am now using Vi-King Crusader AP front struts and shocks and these have totally flipped the script on the way I setup the car and drive it after a season with them. I just got a set of the new triple adj rear shocks but haven't tried them out yet. Just a few street miles so far.

Thank you, this is great feedback!

I might just stick with my current spring set up for a little while longer. My dual rates go up to a 1200 lb rating which these cars love.

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