I’m about to purchase the Koni yellow / Ground Control custom coilovers from the ground control website. What I am wanting to know is what spring rates are you guys running? There are selections for the spring rates on the site ranging from Daily, Race and custom. What is the best for our cars? Thanks in advance!!
580F/440R is what i have. i dont know anything about the science of spring rates but these seem to be just fine for me. i auto x and do a lot of spirited driving. i didnt choose my rate either. its just what came in the box.
^Those rates are pushing it as far as the shocks are concerned. The general recommendation has been that 500lbs is the upper limit of what the off the shelf Koni Yellows can handle. But plenty of people have run 500-600lb springs without problems - you’re likely to just wear out the shocks a bit sooner and you won’t get the control you would with a lower rate spring.
To the OP, you should give more info:
- primary use of this car? (How much of each type of driving:Track, autox, daily driver, Sunday driver…)
- your experience level
- what other mods are done to the car? What do you have planned?
I agree with Colin. The OTS rates of 330F / 250R work well for a daily driver that sees some autocross or occasional track day on street tires 180 treadware or more and will be easy on the konis.
I have a NASA time trial car, and i’ve been stepping up my rates as time goes on. I’m running tokico illuminas. I started with the GC OTS rates. Next i went to 8k/6k. Not too much improvement. Next i tried 10k/8k. This felt very good. Balance was neutral, body roll was fairly controlled, and the tokicos handled the rate well (i only drive to and from the track, not daily). For this season, i’ve just stepped up to 12k/10k. I’m not sure how it will handle or how well the Illuminas will control the springs. The switch to 12k/10k was motivated by stepping up to Nitto NT-01 r-comps and being limited in my front camber by class rules.
The primary use for my car is a daily driver. I want to eventually have my da strictly for the track, for the time being I would like to have a Daily/track car. My driving experience is minuscule, I drive mountain passes and such often with some friends. Right now I am running tokico illuminas with skunk 2 springs. Just ordered a hyper flex bushing kit and starting my suspension overhaul.
In that case I’d suggest going as high as you can within the limit of the shock and your comfort level. When I was younger I ran 550/450 and like it, but now I think those rates would not be all that fun for a daily. Everyone’s opinion on this will differ, so we can’t choose for you.
I wouldn’t go any lower than the OTC rates and not any higher than 500/400. I’d probably err on the side of going softer rather than stiffer for daily comfort. And try to use larger sway bars, fresh bushings, and great tires to get a little added performance for track days. The right alignment and tire pressures also make a big difference.