Let's Talk Spring Rates

[PoweredbyHonda]

Hey guys, I'm new to this forum but i have been playing with cars for a while. I'm in the process of lowering my crx and get it flush but i will also be doing auto x events so i won't be scraping chassis. So it looks like 500F 650R is very common, what's the best spring rate after lowering that's very stiff for auto x. I don't care if it's not comfortable... What rates do you have, how does it feel? I don't see many stanced crx's so we'll see how this goes.

[Kielan]

Well what struts do you have?

[PavelK313]

To choose proper spring rate you must take into account your cars weight, your car weight distribution (with you in it) and how much suspension travel do you want (exact numbers).

[Daviticus]

Just how low are you looking to get? Also, what wheel/tire sizes are you looking to run? Keep in mind if you're changing your wheel/tire combo for track days, you'll need to clear those with minimal/no adjustment if you want it easy.

My previous daily was a '91 Si literally slammed on some beefy 13" wheels and tires.





The pictures above are somewhat deceiving, the gap you see between the resonator and ground is just over an inch. I had GroundControl coil sleeves on all four corners with 8k [approx. 450lb/in] 7" springs. Up front I "ghetto modded" the tophats by pulling the bottom rubber bushing out and placing it on top of the top bushing, leaving the washer on the strut rod to bottom-out inside the tophat. After cutting the OEM bumpstop in half, I had roughly 2" of suspension travel before the crossmembers and LCAs would hit the ground. From there, I had maybe an extra 1/2" before the bumpstop, and an entire inch before the strut bottomed out internally. Struts were Tokico Blues, for the record. Wheels were Mahle-BBS 13x6 +13 with 215/50HR13s bulged around them.

At one point during the build I had a set of Rota Circuit-8s, 16x7 +42 I believe, on the car. Tires were mismatched 205/40HR16 China-brands. Just to show you the difference between the 13"s and tucking 16"s at the same ride height [the ride height did not change with the engine installed, fyi]:





As far as ride and handling, it was bone-jarring to say the absolute least. Granted, the car was completely stripped, save for heater core and front seats [even gutted the doors and pulled the bumper supports], and the 8k rear springs allowed the car to constantly oversteer especially on lift-throttle instances. I would rather have had 6k [~350lb/in] springs out back, and adjustable struts [KYB AGX or Tokico Illumina] to at least somewhat tune compression stiffness. The car handled like it was on rails, even with garbage tires.

My CRX, with me in it, and a half-tank of 85 octane, weighed 2104lbs.