PN for Swift Springs on KW Coilover Body

[autoxtrackdrift]

What's the correct part number and length for a pair of Swift 8k rear springs to go with a KW/Racecomp coil over?


Z60-203-080 seemed to be in the ball park if I ditch the helper spring.


Has anyone used this shock/spring combination?

[strat61caster]

8" is too long imho, I had an 8" 500# spring on my Bilstein and struggled to set height where I wanted in the rear, 7" 425# spring without helper was near perfect iirc and should be extremely similar to what you are looking for. 6" might need a helper spring which I think is their preferred setup.

I'd expect RCE would be able to respond to the question tomorrow if someone who has a set doesn't chime in first.

[Racecomp Engineering]

You want 60mm ID. 6 or 7 inch length should be okay depending on where you want to set the ride height. May use helper either way with the 8 kg/mm spring rate, but definitely with a 6 inch spring.

- Andrew

[autoxtrackdrift]

Is there any difference in travel between a 6 inch spring with a helper and a 7 inch spring alone?

Thanks!

[strat61caster]

Originally Posted by autoxtrackdrift

Is there any difference in travel between a 6 inch spring with a helper and a 7 inch spring alone?

Thanks!

Any decent spring should have as much or more travel than your damper/bump stop which is tropically your limiting factor for wheel travel. A 7" spring will typically have more stroke available than a 6" spring and a zero rate helper will only change your perch height and have ideally zero impact to your wheel travel.

Check out the Eibach Motorsports catalog, they list a lot of information about block height and travel and you can compare spring stiffness and heights. You will see a general trend with small hiccups where the spring wire diameter increases but iirc is not listed.

https://eibach.com/us/rt-2-catalog-downloads.html

[wparsons]

Originally Posted by autoxtrackdrift

Is there any difference in travel between a 6 inch spring with a helper and a 7 inch spring alone?

Thanks!

You can get more travel out of a longer spring before getting coil bind, but that assumes the damper has enough travel for that to be an issue with the shorter spring. On the KW/RCE bodies a 6" spring won't be binding, so you're fine either way.

[Racecomp Engineering]

You can also look up the travel numbers for most of the major spring manufacturers.

- Andrew