Originally Posted by
WhiteJames
Most street focussed coilover use progressive rate springs. It is difficult to work out the spring rate as the rate changes throughout the spring compression. Add the complexity of separate low speed and high speed compression rates, and it all gets very complex. I found that in order to make the info palpable to forums readers, you can generalise spring rates, albeit with a very broad margin for error.
In very general terms, I found that my first Eibach ProKit/Koni FSD strut kit about 15% firmer in spring rate than the OE springs (mainly in the mid range spring rate due to progressive natural of springs, with less spring rate earlier in the compression cycle). Replacing that kit with the KW V3 coilover had springs rates about 35% above the OE MK5 Golf GTI spring rate. The KW V3 was good for bitumen freeway (not concrete) and short drives of less than 2 hours in duration. Otherwise, even on softest setting, I found them too firm for Sydney roadways, concrete and long distance hauls on country roadways (H&R bars didn’t help, but H&R sway bars were not so much an issue with the Eibach/FSD kit).
By turning the KW V3 down to their softest on compression and rebound setting, they did exhibit a slight tendency towards being underdamped. Of course, if you turn the KW V3 up to almost full hard, they are most like going to be overdamped and not let the spring do its job. The damping range has to fit the spring rate. With coilovers, this is about mid level damper settings. My concern with the new KW Dynamic (DCC) coilover is that the spring rate may be too high to begin with; regardless if the damping can be made comparable to OE Comfort mode on the DCC Mark 6 Golf GTI. Same deal with hard being like the Clubsport KW coilover. Clubsport coilovers, to my knowledge, are basically the KW V3 with a linear spring having a higher spring rate and camber top plates that are designed to work with semi-slicks on the road/track.
I’m finding it difficult to fathom how KW are able to have a coilover act like a standard DCC Golf GTI in Comfort & Normal mode in soft setting, and then act like a KW Clubsport coilover without any change in spring rate. The damper rate has to work around the spring rate. I’m interested to know where is that starting point for the KW Dynamic coilover. When I ran my KW V3 on almost full soft settings, I found that the comfort/sports HPA Motorsport KW coilover spring rate did a better job of matching the spring rate to the lower damper rate than my softened KW V3 coilover. In other words, the HPA KW coilover kit was a better spring rate match for the softer damper settings. Having the KW Dynamic coilover cover such a wide range of damping rate – from KW Street Comfort to KW Clubsport – seems to me to be an extremely difficult task. In my experience, it meant change suspension 3 times over from Eibach ProKit/FSD to KW V3 to HPA Motorsport KW street/comfort coilover.
Cheers.
WJ
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