Coilover spring length - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 03-28-2011, 11:56 AM   #21
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I acutally have 336 lb rear springs at 6" and they are binding. what shocks are you on?

I've always had binding issues on springs others can get away with, my car is heavy...calculations put it at 567lbs on the rear corners.

My springs are only 3.75" long at rest, per Tein's specs they have a max stroke of 3.7", so I only have 1.45" of travel before bind...I'm pretty sure my bump is getting compressed, but the spring is binding just before the bump will stop the shock travel.


here's mine at rest, ride height of 12.75" but I had to preload them a bit to bring it up to that:

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Coilover spring length-2011-03-22_11-54-44_427.jpg  
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Old 03-28-2011, 12:01 PM   #22
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I have revalved R-Package Bilsteins which have a shorter body that the standard Bilsteins. I have been keeping an eye on the springs (Eibachs on Ground controls BTW)to watch out for this, but I see no evidence of bind like marks on the springs and I have never felt the (so I'm told) sharp bottoming out either.

One of these days I need to actually measure to see if it is possible with a big enough bump, but so far, no problems. I don't have my corner weights on hand at the moment, but I do recall them being less than yours.
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Old 03-28-2011, 12:04 PM   #23
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I did the math, since the 6" 336lb spring is compressed 2.5", that puts the weight to 756. Multiplied by the motion ratio of 0.75 in the rear, brings the weight on that corner around ~565 lbs.

But like I said, never head of anyone else with Teins complaning about it.

Luckily I found some 6.7" 336lb springs for $45 shipped for the pair. Gives me .7" more travel in the rear before bind (assuming all things equal). I think the ones I purchased have less coils so therefore more max stroke before bind.
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Old 03-28-2011, 12:11 PM   #24
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It looks like you have the marks in the powder coating a bit, yes? I had my car corner-weighed last spring and have the numbers. I'll look them up when I get home.

I do plan go to a 7-8" spring at some point to be safe but for now, it seems to work pretty well. The car is not DD though so I don;t put it through all the normal assault and battery most suspensions get on our MN roads.
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Old 03-28-2011, 02:03 PM   #25
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Brain, this might be a better option:
http://www.sg-motorsport.com/store/p...oducts_id=1142
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Old 03-28-2011, 02:05 PM   #26
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I think I may stay with 6" f and 7" rear. Where's the best place to buy nb rear top hats?
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Old 03-28-2011, 02:15 PM   #27
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Quote:
Originally Posted by 89325iturbo View Post
I think I may stay with 6" f and 7" rear. Where's the best place to buy nb rear top hats?
You're going to have ride height issues. let me rephrase: lack of low-ness issues.



Judge for yourself how much adjustment room youll have. Assuming the picture above shows the springs compressed down to 4.5" under weight and that puts me at a 12.75-13.0" ride height. If they were the same length but 100lbs heavier, theyd be at 5.11" compressed under body weight. I'd have to lower the spring perch about half an inch lower just to see the same ride height. I really wouldn't have anymore room to adjust the car lower. Unless you get the real koni sleeves which allow the collars to go down past the circlips, unlike the collars I have, you'd be screwed.
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Old 03-28-2011, 02:17 PM   #28
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Quote:
Originally Posted by wannafbody View Post
Brain, this might be a better option:
http://www.sg-motorsport.com/store/p...oducts_id=1142

why would that be better? sure they will allow me to reduce the preload, but they are also 3x the price of my solution and are too narrow ID.
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Old 03-28-2011, 02:21 PM   #29
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Quote:
Originally Posted by Braineack View Post
You're going to have ride height issues. let me rephrase: lack of low-ness issues.
Depends on the shock and the lowness needed. Even if I went to 7" springs, I still could go down another inch and a half, which would put me around 10.5" front and 11" in the rear. Not Clubroadster slammed, but pretty damn low.
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Old 03-28-2011, 02:25 PM   #30
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Quote:
Originally Posted by Adam777 View Post
Depends on the shock and the lowness needed. Even if I went to 7" springs, I still could go down another inch and a half, which would put me around 10.5" front and 11" in the rear. Not Clubroadster slammed, but pretty damn low.

Look at my post again. I'm running koni shocks with NB tophats.

Those are 7" 300# springs and the car was at 12.75-13.0" ride height. Thre is barely enough room to go lower with my collars.

You'll be cutting it close is all I'm saying. YMMV
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Old 03-28-2011, 02:27 PM   #31
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Sorry, misread. Too much time spent at CR......
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Old 03-28-2011, 02:30 PM   #32
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I guess it really depends on the sleeves you use. If you get genuine Koni sleeves with the single locking collar, I think you'd be fine with 400# 7" springs. In my case I don't think they'd fit due to my cheapo ebay sleeves that have to rest on the spring perch.

and if your car is lighter than mine...
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Old 03-28-2011, 05:53 PM   #33
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So 5"f and 6"r would be the better option then like stated above. What can the regular Komi sports hold for spring rates front and rear. I was thinking maybe a better option would be to use Komi sports all around with rates of 500-550f and 400r with nb top hats all around? I would like a decently low ride height.
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Old 03-28-2011, 05:54 PM   #34
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Koni* phone changes it.
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Old 03-28-2011, 05:57 PM   #35
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Just spring for the Koni perches. They are relatively cheap and you'll be able to adjust height as needed.
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Old 03-28-2011, 06:17 PM   #36
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Brain, the tender springs are more expensive, I'll grant you that, but I'll bet they'll improve ride quality. I put a set on a pair of rear Bilstein NA shocks with factory valving and they improved ride quality.
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Old 03-28-2011, 06:28 PM   #37
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Quote:
Originally Posted by 89325iturbo View Post
So 5"f and 6"r would be the better option then like stated above. What can the regular Komi sports hold for spring rates front and rear. I was thinking maybe a better option would be to use Komi sports all around with rates of 500-550f and 400r with nb top hats all around? I would like a decently low ride height.
500/300 is pushing the limits of the sports.
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Old 03-28-2011, 06:28 PM   #38
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Quote:
Originally Posted by wannafbody View Post
Brain, the tender springs are more expensive, I'll grant you that, but I'll bet they'll improve ride quality. I put a set on a pair of rear Bilstein NA shocks with factory valving and they improved ride quality.
ill take my chances with the cheap solution. The Tein helper springs are much cheaper at $48 a set (2). MSRP.

I think the longer springs with be the ticket, but I wont rule it out to remove preload from the spring and extend the stroke before bind. but like i said, I'm like ~.5" off.
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Old 03-28-2011, 06:52 PM   #39
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I'm about to put ~350/225 Hyperco springs on my daily w/ Ground Control perches, any thoughts on which free length for NA Bilstein HD's with NB upper mounts?
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Old 03-28-2011, 07:05 PM   #40
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Depends on the spring rate, car weight, desired ride height, and the difference between spring's free length, adn block length.

Basically you want the spring's installed length, *at full bump*, to be just a bit longer than the spring's block length.

Use FCM's spreadsheet.
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