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Old 05-09-2019, 04:11 AM   #1
ssmokeyy
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Join Date: May 2018
Default 03 wrx with bc racing coilover kit. Too stiff.

I got a 2003 wrx with bc racing coilover kit came with the car. The kit is to still stiff. I'm thinking about ordering some eibach coilover springs 2.5 Id 8 inch length 450 front 400 rear pound rated. Would this be a bad idea and would this be to soft to keep her sporty? I have a built motor doing 450whp. The new tires will be bfg comp2 a/s. 225/45-17. Not going crazy low probably will set it up inch lower than stock height.
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Old 05-09-2019, 07:23 AM   #2
Blktrax
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Unless you plan to spend coin to send the units off to be re-valved to match the new spring rates.... just don’t bother. Mismatched springs to valves will likely result in very poor damping resulting in worse handling.

Things to try first.
1.Set all the adjustments to full soft
2. Remove spring preload, (lift vehicle) collar at the bottom of the spring loosen till spring is completely unloaded, turn collar up till spring doesn’t rattle add 1/2 turn. (most ppl never set this correctly when they mess with ride height.)
3. Set ride height using shock body, lower collars , not spring load.

I’ve got Feal 441’s with 8kF, 6kR , basically set full soft rear and 4 clicks from full soft front , below 35 yes it’s stiff; over that and the faster the speed the more it smooths out. But this was several trials of adjustments to figure out where I wanted the best grip and behavior of the car under certain conditions (the whole point of coilover adjustments)

Option 2 = set it and forget it.
Get a full set of KYB struts with Eibach Prokit or Sportlines if you want the soft factory ride with more lows.
Or the Tokico and RCE spring combo if you can still find them.

Side note- 225 on all seasons with 450hp is a waste. 245-40-17 and a strictly summer tire would be better suited to that power level. And you’re going to need a 6-speed swap.

Last edited by Blktrax; 05-09-2019 at 07:35 AM.
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Old 05-09-2019, 09:58 AM   #3
ssmokeyy
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Will 245/40-17 fit with out rubbing? Also this is a daily driver. Just because it has 450 whp doesn't mean I'm out racing around and shifting hard. The 5 speed handles the power nice part I hate is the wrx act stage 2 clutch. I'm going to order a sti stage 1 kit to smooth the shifts out. When i had this coilover kit set to soft it would buttom out and hit the bump stops. Could that be wrong pre load set?
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Old 05-09-2019, 07:02 PM   #4
Mike_Feal
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2003 Lexus IS300
2JZ 620HP/595TQ

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Keep in mind that spring preload DOES NOT affect spring rate or ride feel. As long as you don't have too much preload that you top out, or not enough preload to keep from bottoming out, it will otherwise not affect ride feel to adjust preload. If you are hitting bumpstop currently you do not have enough preload. I don't think BC sets them out of the box and unless you adjusted them yourself it likely has 0 preload. I would recommend 6mm front/3mm rear as a baseline, but what you really want is about 35% droop. Don't go by hand turns, measure the free length of the spring and then use the collars to compress the spring until it is 6mm/3mm shorter length comparatively. Of course these measurements will be with the car in the air.

MCA make a great video explaining how preload works, check it out:

450lbs/400lbs springs are likely higher rate than you have on the car currently. These equate to about an 8k front 7k rear. Feal offers 7k/5k (392lbs/280lbs) as standard for reference.

Last edited by Mike_Feal; 05-09-2019 at 07:10 PM.
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Old 05-09-2019, 10:26 PM   #5
Blktrax
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Quote:
Originally Posted by ssmokeyy View Post
Will 245/40-17 fit with out rubbing? Also this is a daily driver. Just because it has 450 whp doesn't mean I'm out racing around and shifting hard. The 5 speed handles the power nice part I hate is the wrx act stage 2 clutch. I'm going to order a sti stage 1 kit to smooth the shifts out. When i had this coilover kit set to soft it would buttom out and hit the bump stops. Could that be wrong pre load set?
245/40-17's will fit without modification without aggressive lowering. Back when I wanted more lows I had to roll the rears. Knowing what I do now , and not being as low; I wouldn't have had to roll at my current ride height, and now running 255/40-17 on 17x9 +42.

https://forums.nasioc.com/forums/sho...&postcount=785

Current setup is 1/2" taller ride height than the pictures above.

Last edited by Blktrax; 05-09-2019 at 10:31 PM.
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Old 05-10-2019, 04:25 AM   #6
2pot
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Quote:
Originally Posted by Mike_Feal View Post
Feal offers 7k/5k (392lbs/280lbs) as standard for reference.
Why that spring rate split? Aren't you creating a pitching problem? Why not use flat ride frequencies to settle the chassis?

Last edited by 2pot; 05-10-2019 at 04:54 AM.
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Old 05-10-2019, 11:20 AM   #7
Mike_Feal
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2003 Lexus IS300
2JZ 620HP/595TQ

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Quote:
Originally Posted by 2pot View Post
Why that spring rate split? Aren't you creating a pitching problem? Why not use flat ride frequencies to settle the chassis?
This is what Odi had found to work best for comfort and light track use on the chassis. He did plenty of testing with our bugeye and SF forester with these and different rates and had found these to work as a nice middle ground. Ideally for a more track based setup the split would be a little closer together, but in a real world situation we have 100's on drivers on these rates with no complaints.
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Old 01-29-2021, 04:23 PM   #8
Jaws4God
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2003 Impreza WRX 207
02C, 42C World Rally Blue

Question

Quote:
Originally Posted by Mike_Feal View Post
Keep in mind that spring preload DOES NOT affect spring rate or ride feel. As long as you don't have too much preload that you top out, or not enough preload to keep from bottoming out, it will otherwise not affect ride feel to adjust preload. If you are hitting bumpstop currently you do not have enough preload.
I set mine to 2 clicks from full soft, and my ride still seems very bumpy.. so i'm curious if the preload was set to stiff.. could that be possible?

Quote:
Originally Posted by Mike_Feal View Post
I would recommend 6mm front/3mm rear as a baseline, but what you really want is about 35% droop. Don't go by hand turns, measure the free length of the spring and then use the collars to compress the spring until it is 6mm/3mm shorter length comparatively. Of course these measurements will be with the car in the air.
so does that mean i'd loosing the preload until the spring is almost loose, and then tighten it from that point to 6mm ?

Thank you!

~~~ 2003 WRX ~~~
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Old 02-12-2021, 11:21 AM   #9
Jaws4God
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Location: North Carolina
Vehicle:
2003 Impreza WRX 207
02C, 42C World Rally Blue

Question

Quote:
Originally Posted by ssmokeyy View Post
I got a 2003 wrx with bc racing coilover kit came with the car. The kit is to still stiff. I'm thinking about ordering some eibach coilover springs 2.5 Id 8 inch length 450 front 400 rear pound rated.
Did you end up getting these? I had a shop say mine has 10kgf and 12kgf so that is why my ride is so rough..

Thanks!
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Old 02-16-2021, 07:35 PM   #10
Mike_Feal
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Member#: 462296
Join Date: Feb 2017
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Location: Riverside, CA
Vehicle:
2003 Lexus IS300
2JZ 620HP/595TQ

Default

Quote:
Originally Posted by Jaws4God View Post
I set mine to 2 clicks from full soft, and my ride still seems very bumpy.. so i'm curious if the preload was set to stiff.. could that be possible?

So does that mean i'd loosing the preload until the spring is almost loose, and then tighten it from that point to 6mm ?
1) Doubt it's a preload issue. Probably just a damping issue.

2) Like I mentioned above, measure the free length of the spring and then compress it to add preload. It's literally in the quote you quoted
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