Re: For those that are using the Mazdaspeed MS3 coilovers, or KW v3 coils, what are
[quote author=danielj link=topic=172276.msg3655075#msg3655075 date=1273620339]
Do you know which version of KW V3 coilover you have for the Mazdaspeed3? KW had a bad batch out where the helper spring would bind or fully compress causing it to bottom out. A few local guys have had to send theirs back to KW for replacement.
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Mine are the MS coils, the KW's are some pics I found on the net, they are MS3 KW v2's......
[quote author=budgy link=topic=172276.msg3655082#msg3655082 date=1273620581]
on the main spring I count 7 turns of wire on the speeds, and 6 turns of wire on the KW's
helper spring is 4 turns of wire on the speeds, 6 turns on the KW's I think....
so even if we assume the height and gauge of wire on the main coil is the same the MS would have a slightly stiffer spring rate.
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Are you sure that is not the other way around?
It is my understanding more coils = lower spring rate, if everything else remains the same.
The spring calculator I used showed the Main Spring for the MS coils to be softer, using the same assumption as you:
http://www.pontiacracing.net/js_coil_spring_rate.htm
Using the calc there, and the "ballpark" (taken with a tape) measurements of my spring gave me KW coils 400 lbs/in (what KW says they are), MS coils 335 lbs/in
The numbers I used were Free length 200mm (not needed for the calc), coil width 84mm, wire diameter 11mm
KW free coils 5.2
MS free coils 6.2
How did I arrive at number of coils.
Well KW publishes a spring rate of 400 lbs/in for the front, so I put in a number that created that from the other measurements I had. I then added 1 coil to that, for the MS coils.
I know my" taken with a tape, not a caliper", measurements will be a little off, and so I was surprised when the number of coils was "in the ball park"
modulus of spring steel X wire diameter
spring rate = -----------------------------------------------------
8 X number of active coils X mean coil diameter
So if everything else remains constant, an increase in coils DECREASES the spring rate.
Counter-intuitive for me anyway.