Coilover spring rates - Suspension and Brake Forum

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Coilover spring rates
Tuesday, March 12, 2013 9:44 AM
I'm picking up a set of Bc coilovers with the extreme drop and swift spring upgrade.

Stock they send 6k/4k springs. I'm assuming the 6k are the front.

I'm wondering what spring rate I should go with. I want to lower it fairly low but keep it smooth for daily driving.

I'm thinking go 8k/6k??

With those of you that know about this sort of thing what do you think?

Re: Coilover spring rates
Tuesday, March 12, 2013 10:31 PM
6k? As in- 6 THOUSAND? I hope not. For a street car, you shouldn't be running over 5-600 lbs/in. And that's REALLY stiff. Anything more than that and you've lost pretty much all compression and ride quality. Most bolt in lowering springs are only around 200lbs/in, maybe a bit more at most.
.



Re: Coilover spring rates
Tuesday, March 12, 2013 11:48 PM
Well those are racing coil overs and start around $2000. They are fully adjustable and carry extra fluid. There is no point in buying them if you want a smooth ride. With that much spring rate you would not even be able to adjust the rebound or dampening as the spring would never compress. It would be like having a welded suspension.




On the inside my car looks like a fighter jet.
Re: Coilover spring rates
Wednesday, March 13, 2013 9:39 AM
James Cahill wrote:

6k? As in- 6 THOUSAND? I hope not. For a street car, you shouldn't be running over 5-600 lbs/in. And that's REALLY stiff. Anything more than that and you've lost pretty much all compression and ride quality. Most bolt in lowering springs are only around 200lbs/in, maybe a bit more at most.
.



That's measured in kg/mm, not lb/in.

8k/6k = ~450 / ~337

Stock GC sleeves come with 375 / 250.




________________________________________.
Still not low enough for a signature.

Re: Coilover spring rates
Wednesday, March 13, 2013 9:58 AM
I believe my h&r's are around 300lbs/in and believe me even with stock mounts and my d-specs almost all the way soft its still STIFF. Riding on the highway can be almost painful. If I had to do it again I'd go with the pro-kit from Eibach.

I go through mounts pretty quick too...

Edited 1 time(s). Last edited Wednesday, March 13, 2013 9:58 AM


"In Oldskool we trust"
Re: Coilover spring rates
Wednesday, March 13, 2013 11:11 AM
I know 600lb rears.....do not compress at all....at least they do not feel like they compress at all.

Anything over 500lb or not over 9K for the front. I think

I would think the 8K or 446lb front would work out well.

Also the 4K or 223lb might be a little weak. Maybe something like 5.25-5.5K or 293-307 would be better. I would 6K for the rears would be the limit I would want to do to. I hope the coil overs have adjustable rebound and damping.


Most cavalier weigh in around 2600lbs and are around 56 to 44 weight biased....so1456lbs in the front and 1144lbs in the rear. This is the weight of the car... So you really do not want to go over 1092/2=546lbs in the front and 858/2=429lbs in the rear. <---- That would be a REALLY hard ride in my opinion.


I know SCCA people have general rules of thumbs for this, and that is what I based the above on, but at the 500lb front and 430lb rear....it will be DAMN hard.

You DO not want to get the front or the rear springs to hard / to soft. You need to stay kinda close in the ratio.





Re: Coilover spring rates
Wednesday, March 13, 2013 3:53 PM
I was thinking of going 7k in the front and 5 in the back....I was originally just going to go with 8k/6k since im a fully loaded 03 with a fair amount of sound deadener and every option there is. So I placed my weight around 3000 lbs atleast with me in it.

Im going with the swift spring which from my reading feel alot softer than they are due to the way they are made and materials.

Since its a daily and the roads are crap here I do want a decent ride....(I know everyone wants low and stock ride) I want low and a decent ride....

The coilovers are adjustable.
Re: front to rear spring rates. Coil Spring rates, Weight distribution
Thursday, March 14, 2013 6:04 AM
So if your car is 3000lbs that would be 1620lbs front and 1380lbs rear... for 54 to 46%.

The stock springs are 6k aka 335lbs and the rear are 4k aka 223lbs. so they are set up for 60 to 40%.

To keep the same ratio with 7K / 391lb fronts. You would need 260lb rears or 4.6K. This is to keep the same ratio that the original springs are.

To keep the stock ratio with 7K / 391lb fronts. You would need 290lb rears or 5.1K.


SO, what I'm saying is 7K fronts and 5K rears should work out well if you weight distribution is close to stock.





Re: Coilover spring rates
Thursday, March 14, 2013 9:47 AM
Twenty4z wrote:

James Cahill wrote:

6k? As in- 6 THOUSAND? I hope not. For a street car, you shouldn't be running over 5-600 lbs/in. And that's REALLY stiff. Anything more than that and you've lost pretty much all compression and ride quality. Most bolt in lowering springs are only around 200lbs/in, maybe a bit more at most.
.



That's measured in kg/mm, not lb/in.

8k/6k = ~450 / ~337

Stock GC sleeves come with 375 / 250.


Ok. That makes sense.
.



Re: Coilover spring rates
Thursday, March 14, 2013 9:50 PM
Youre getting the Extreme Drops but you want it fairly low and smooth? Seems like something doesnt line up here.

If youre going to really really dump it you want to get the stiffer ones so your arent rubbing your tires and bottoming out on stuff constantly. Otherwise the 6k/4k would be fine.



Re: Coilover spring rates
Friday, March 15, 2013 5:17 AM
Ive already asked the seller..
Extreme drops ride like the normal bc's And since lowering it doesn't shorten shock travel it shouldn't adversely affect it.

I am only going to do a 2" drop....basically eliminate my fender gap I have.

Re: Coilover spring rates
Friday, March 15, 2013 3:22 PM
Philly D wrote:

Ive already asked the seller..
Extreme drops ride like the normal bc's And since lowering it doesn't shorten shock travel it shouldn't adversely affect it.

I am only going to do a 2" drop....basically eliminate my fender gap I have.


It wasnt the shock performance I was talking about. Its the fact that if you absolutely dump a car you need stiffness of the springs to keep from destroying your wheels, tires and undercarriage. I wasnt sure what route you were going.

Seems like 2" should be in the normal range of drop for a normal BC coilover unless the cost is the same for the Extreme drop. Do they advertise the Extreme Drop anywhere on their site? Ive been looking at some for my Accord and I havent see anything about anything extra besides the Swift spring upgrade.



Re: Coilover spring rates
Friday, March 15, 2013 4:10 PM
The extreme drop is free or the same cost.....as well as rear adjuster extenders.

I believe with the extreme drop they run a shorter shock cartridge...on average a inch shorter.

Contact Circuit motorsports....thats who im going through.
Re: Coilover spring rates
Thursday, December 12, 2013 7:33 AM
So did you ever get them?





Re: Coilover spring rates
Thursday, December 12, 2013 4:26 PM
Oh ya..

I bought them shortly after this thread.

Installed them a bit ago. Check out my build thread.

They ride good. Pretty stiff for rough roads but smoother then youd think. Im very happy.
Re: Coilover spring rates
Friday, December 13, 2013 5:08 PM
MY Tein coilovers are like 336lb and 250lb.



FU Tuning



Re: Coilover spring rates
Saturday, December 14, 2013 7:28 AM
The 7k/5k is about 392lb/280
Re: Coilover spring rates
Saturday, December 14, 2013 8:50 AM
are you able to get a video of the ride going over bumps in and outside the car?


Image
(write what ever comment you want here)
Re: Coilover spring rates
Saturday, December 14, 2013 9:38 AM
Not at the moment no.

It really does ride nice.

I think if you dont want to be low. Like right now im pretty low. The stock spring rates. BC offers is just fine.

I havent had much time to play with it much though since I work out of town and maybe drive 100 km a month.

Edited 1 time(s). Last edited Saturday, December 14, 2013 9:38 AM
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