Coil-over Spring rates

[69boss]

I'm having issues with my ISC coilover setup where I think it is way too stiff up front. The spring rates are 12k front and 14k rear. I looked up other performance coilovers to compare and found Pedders at 7k/14k, BC at 7k/14k, Ohlin at 9k/14k, and Teins at 7k/13k. The ride is very rough, and I'm wondering if I should swap out springs to like an 8k spring. I use the car for daily driving with occasional track and autocross use. Trying to fix the ride quality before just removing them and going back to stock lol. Anyone with coil-over knowledge please chime in.

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[TeeLew]

Is the rear spring on the arm or the damper?

 

[69boss]

Is the rear spring on the arm or the damper?

It’s a divorced coil over setup so the rear spring goes where the stock spring goes.

 

[TeeLew]

For the street, I could see dropping the front to 6 kg/mm. For the track, I'd be surprised if you get below 8. Your 12 rate would be a stiffness level more appropriate for slicks and a smoothish track.

 

[shogun32]

how much suspension travel do your (especially) front CO have? how much when you factor in the bump stop? At rest, how much have you used up? Ideally you want to be sitting at 25-30% used but that may leave far too little for bump absorption.

 

[69boss]

Ya I have tried lots of adjustments. Under 6 clicks seems very underdamped and bouncy so I stay between 6-10 out of 32 usually. I talked to the company and they said they don't recommend going below a 10k spring with the current valving which I think will still be pretty rough. I'll probably end up going back to stock lol.

 

[shogun32]

damping can't fix wrong spring. The cheap-ass CO guys are using big spring to conceal the fact their damping SUCKS, and that their stroke length is entirely too short.

 

[Andy13186]

I like my pedders rates

 

[69boss]

damping can't fix wrong spring. The cheap-ass CO guys are using big spring to conceal the fact their damping SUCKS, and that their stroke length is entirely too short.

What stroke length and damping should I be looking for. I went with ISC N1 track coilovers based off their lifetime warranty and the American Muscle guy selling me on them over other options lol

 

[AZlb5.0]

If it isn’t a track designated car that front spring is way too stiff. You have to see what you’re using the car for. You don’t want a spring rate that’s for slicks on a fairly smooth track. Why? Because you’ll run into what’s happening with you. If you’re not going to track the car the. Get something that’s suited for what you’re going to be doing. No need for such a high spring rate if all you’re doing is street/canyon carving.
good luck

 

[69boss]

If it isn’t a track designated car that front spring is way too stiff. You have to see what you’re using the car for. You don’t want a spring rate that’s for slicks on a fairly smooth track. Why? Because you’ll run into what’s happening with you. If you’re not going to track the car the. Get something that’s suited for what you’re going to be doing. No need for such a high spring rate if all you’re doing is street/canyon carving.
good luck

I use my car for autocross and track, but also use it as a daily. Not just a street car. The setup I have should be used for a dedicated track car that does not see the street very often. I didn't know that at the time but the American Muscle guy convinced me to get this over the FP Track Handling kit. Sold me on being able to adjust it for daily driving then adjust it for the track on the fly.

 

[AZlb5.0]

I use my car for autocross and track, but also use it as a daily. Not just a street car. The setup I have should be used for a dedicated track car that does not see the street very often. I didn't know that but the American Muscle guy convinced me to get this over the FP Track Handling kit. Sold me on being able to adjust it for daily driving then adjust it for the track on the fly.

Yeah I think he was trying to make a good commission off you. Sorry it turned out that way. I guess it depends on how competitive you want to be at the track also. I’m looking at the pedders extreme coil over set. Take a look it might fulfill what you need.

 

[69boss]

Yeah I think he was trying to make a good commission off you. Sorry it turned out that way. I guess it depends on how competitive you want to be at the track also. I’m looking at the pedders extreme coil over set. Take a look it might fulfill what you need.

They do handle very well but are designed for a specific purpose. I should have gone with the street versions and not the track versions. I've heard good things about pedders and those are more in line with my needs. I kinda want to just get away from coilovers and go back to a simple shock and spring lol

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