Ok so I'm looking into the On3 Performance Turbo system for my Cobra and it requires the K Member kit. I have a question about spring options. It comes with 5 options for spring rates. 12-250, 12-350, 14-130, 14-150, 14-175. What do the numbers mean and how will the ride quality change depending on each spring rate? I'm kinda a noob when it comes to suspension, I'm the guy always looking for more HP not so worried about traction. Thanks ahead of time for any input you guys can offer!!

 

Not sure what the nubmers mean, but I can tell you what I'm running up front on my Cobra, it's 'Kennybrown' tubular K member.

It's Bilstein Coilovers with QA1 springs (8" - 375lbs), low and yet smooth ride. I should've went with 9" - 400lbs, would've been much better.

*Running 8" springs, due to the stock wheels were hitting the 12" springs I previously had, so I had to put 5/16 spacers, BUT not any more, due to putting 8" springs.

Hope that helps.

 

The first number is the height of the spring. For example our stock springs are 14" long, I cut mine down on my Cobra to 12 1/2" for a 1 1/2" height drop. However now that it's settled I'm gonna cut it down to 11 1/2" tomorrow. So the shorter the spring the lower the ride of the car, however unlike stock springs/struts this height is adjustable and is more so used for racing applications. So the shorter the spring the less "lift" adjustment you have which means in relation to stock the car will sit lower which improves handling but reduces ride quality. The second number is the weight load it's made to take. I'm still researching this but from what I gather this is the springs rating as to how low it can drop. The more weight load the lower it can go.

From what I've seen 12" 250lb seems to be a common spring for Cobras.

Again, I'm not 100% sure on all this, still learning myself, but from what I've gathered that's how that works.