I've been running KW V3 coilovers on my NC miata for a few years. No matter how I try to tune these they are so bad for ride quality. I was hoping someone else had experience and can give me advice whether to ditch them or try to fix the issue somehow.
Going over expansion joints or transitions at speed, I feel like I'm running out of travel and hitting the bumpstops hard. To the point where I unconsciously brace myself because it's so uncomfortable sometimes my ass is nearly leaving the seat.
The rear suspension of the NC is a bit short on travel already I believe, and these really don't seem to help things. The spring on the KW is a progressive in the rear. I've tried the max ride height as recommended in the manual. Curiously this is not the max height you can achieve because there are additional threads to continue cranking up the springs to another 1/2", but when physically maxed out the ride becomes even worse. I think due to the spring rate getting wound up too high.
I've also moved the rebound and compression through various stages of their adjustment ranges, nothing seems to give a well damped feel. The rebound seems to either be too fast resulting in a bouncy ride, but if I slow it down to where I get the ride comfort it will pack down over a series of bumps. Any idea what I'm doing wrong? I'm so fustrated the stock suspension is about to go back in.
The NC is actually decent for rear travel, it's the NA/NB that had trouble.
Even with a progressive spring, you don't change the spring rate when raising the perch unless you get to the point where your preload is greater than your corner weight (and your suspension does not extend at full droop). Once the weight of the car is on the springs, preload is no longer a thing. If you're getting decreased ride quality at higher ride heights, that sounds like coil bind. Look for the telltale lines where the coils have come together.
They're a single piece body, IIRC, which means the travel range is not adjustable. So that's something you don't have to worry about.
For adjusting, start with everything soft. Start increasing rebound until the springs come under control. Then start increasing compression to get the transitional behavior you like. You'll have more leeway in your compression numbers.
That said, I don't think KW has a great track record for building for travel. In their ND shock, they are using a primary rear spring that is 8" long. The car has 7.5" of shock travel from the factory, so obviously an 8" spring is not going to work. I think we use 12" springs in that application.
Would you recommend trying the OEM bumpstops with this type of coilover?
They're probably not much different, but if you're spending a lot of time on the bumpstops (and not coil binding) it's a good and inexpensive place to start. NC bumpstops are quite different than the NA bumpstops that started the whole "all Miatas need new bumpstops" thing.
The problem is you're running KW's.
1. Call Keith and get the Fox setup.
2. Install said Fox setup.
3. Sell the KWs to some stance kid.
z31maniac said:
The problem is you're running KW's.
1. Call Keith and get the Fox setup.
2. Install said Fox setup.
3. Sell the KWs to some stance kid.
2nd'd
I often find myself lusting after vehicles based on the aftermarket suspension available. The FM Fox suspension always looms in the back of my mind as (yet another) reason to pick up a miata. It stands out to me as a unique offering, especially for 2-seat roadster.
Don't tell anyone, but the NC Fox is the best of our Fox variants. The others are good suspensions, but the NC version moves the chassis to the next level compared to anything else we've tested on that platform. Is that because the NC has more untapped potential than the others? Possibly. Is it because there hasn't been as much serious suspension development on the NC? Also possible.
But it's worth playing with the KW setup for a while to see if we can make it work better. At the very least, it'll be an education for twowheeled.
I have Fox coilovers on my NC. They're great.
