Coilover spring length
 

How long of springs do i need when putting together a set of coilovers? 7" front and 7" inch rear? I want to be able to go low enough.

Please, be more vague.

lmao. What wheels do I need for a car guyths?

I dont know how thats vague? Whats the typical length used when people are putting coilovers together.

100 units

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a 50 lb/inch spring will compress 15 inches for a spring load of 750 lbs (about normal for a rear miata spring). So you need at least 15 inches plus some more travel plus the coil bind height of the spring. I'd suggest a 36 inch long spring in this case.

ok

I just thought, i would get help with a question. Im not new to coilovers or putting together set-ups. Im sure some of you wouldnt know the ideal lengths and rates for bmw's which is were im coming from.
Im new to miatas and wasnt completely sure what was proper. So sorry about the noob question if it is one.

the number is 23

No its 3

The answer is:

It depends on your desired spring rates and ride height.

Tell us which which perch, which shock, which upper mount, which generation car, and a ballpark spring rate range. I could tell you 5" which works on my shock but won't work on yours.

I was thinking koni race in the front with stock NA top hats 6" spring 650-700 spring rate. The rear koni sport, with nb top hats 7" spring 400lb rate. With some oval track or whatever coilover sleeves Q1A springs. This is for a 91.
Is the koni shock body 2"? Would it be better to keep the shocks the same? To put races in the back as well because of the different dampening chracteristics?
The races are pricy so saving $250 on the rears would be nice.

There you go. finally non-vaguness.

With those rates, you could probably get away with 5"/6"

When I had Koni Sports w/NB hats, 7" 550lb springs were just a little too long if you wanted to get low enough. The 7" 300lb spring I had in the rear was perfect.

Depending how low you go, 6" will work in the rear too. I have 6" front and rear w/ NB fronts, FM rears, and 36mm bumps and have no coil bind issues at 12.5" in the rear.

Please make sure to leave out what spring rates you use.

I currently have 6" springs in the rear and they bind. I wont tell you more because its not important, so therefore 6" springs cannot be used in the rear.

Sorry, just trying to keep in the spirit of the OP ;)

I have 450 lbs in front and 300 lbs rear. I thought I had the rates in my sig, but that was on a different forum.

:)

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:

https://www.miataturbo.net/attachmen...1&d=1301324328

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.

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.

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.

Brain, this might be a better option:
http://www.sg-motorsport.com/store/p...oducts_id=1142

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.

http://www.boostedmiata.com/gallery2...prings+004.jpg

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.

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.

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

Sorry, misread. Too much time spent at CR......

:)

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...

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.

Koni* phone changes it.

Just spring for the Koni perches. They are relatively cheap and you'll be able to adjust height as needed.

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.

500/300 is pushing the limits of the sports.

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.

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?

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.

From my own setup with Bilsteins, FCM bottom perches, NB upper mounts, and Swift springs:

Front springs are 336 lbs/in (6 kg/mm) 8” long Swifts;
Rear springs are 224 lbs/in (4 kg/mm) 9” long Swifts;

(zack morris's phone)

II had 8" 250# springs in the rear with 7" 400# front. Worked great for me

That would take effort, someone's done it before...and it's my daily so I'm not exactly worried about it.

Thanks, how does it ride on the street? This is for my daily so I want it to not make me sick.

This was rec'd to me by Shaikh for 12.25" F / 12.5" R for my 1991.

Revalved NA R-pkg bilsteins, GC sleeve/perch, NB top hats

F: 6" 500lbs/in
R: 7" 325lbs/in

Will this have coil bind? Hopefully, I understood him correctly.

It rides surprisingly well, though not as well as my setup with the stock springs and Bernie's re-valved Bilsteins. Being twice the normal spring rate, though, that's to be expected.

I'd say it's perfectly livable, so long as exceptional comfort isn't one of your primary goals. It's compromised towards not bottoming the bump stops, and it's pretty good at doing that. I forgot to mention, and it's worth noting, that they're Shaikh's re-valves.

I'd leave mine as is, but the damn tires are always rubbing the fenders and I'd like to auto-x this car. The perfect balance on this car was when I had MSM springs on it, although it was skyjacked. Any thoughts on what those MSM rates are?

According to Shaikh's spreadsheet they're 215/158. That's probably a near perfect compromise between fast road work and comfort, at some reasonable ride height of course. But they might be a tad soft for autox, where I think the 350/225 rates probably have an advantage. On the other hand, a friend of mine does quite well autox-ing his 94R with stock rates. Another thought is that perhaps you could also go with longer bump stops (58mm) which effectively gives you a more rapidly increasing progressive spring rate.

While you're mulling over the 350/225 Hypercoils, you might give a thought to their 8x225 / 10x150 springs. They're effectively the same rates as the MSM springs you found worked so well, but might work with your GC/NB setup as well.

Shaikh wouldn't recommend a setup susceptible to coil bind. Hopefully you understood him correctly.

Im a little more confused on what i want now. I was thinking maybe
Koni sport front 6" spring 450 rate with koni sleeve/perch nb top hat
koni sport rear 7" spring 350 rate with koni sleeve/perch nb top hat
Big sway bar in front.
I want something capable of going low enough, but with a decent ride quality and handleing. Im not looking for the best, just a set-up that will get the job done for what i want it to do. Its a second car that will mostly get street driven as i live in the country with nice driving roads around.

Oh also wheres the cheaspest place to buy the nb top hat conversion at? Is there some spec miata sites that sell it for cheap.

Those rates are pretty close to what I have and they ride well with my revalved Bilsteins. The cheapest place to get NB tophats is used or from Mazda Motorsports (which you need to register for and submit racing/autocross results for, but it is totally worth it.).

First off, buy NB shocks. then get the OEM NB mounts for cheap from a dealership.

http://y8spec.com/suspension/NB_mounts_to_NA_v1.gif

And your ride height will go up an inch and a half. Otherwise, yeah, that's the solution.

Wait, are you suggesting that route with adjustable bottom perches? Actually, that should work and there's no worries about NB top mount fittings cobbled to work with NA shocks. Also, NB shocks are valved pretty good from the factory, unlike their NA cousins which are shit out of the box. Good idea.

So nb shocks and top hats, with adjustable coilover sleeves will still be able to go as low na shocks with nb top hats? If they're an 1-1/2 longer how does that work? Wouldnt the shock just be compressed an inch and half more? i thought you would want shorter shocks to be able to go lower.

You have to knock the tabs off the NB shocks to get the sleeves to sit on the circlip.

what's this about an inch and a half? NB shocks with NB mounts swap directly over to an NA...

I think the ride height issue is only when swapping NA running gear for stock NB gear due to the different spring lengths.

That's the issue, and that's why Hustler said his MSM setup was skyjacked.

I believe the shocks are also a bit longer, but the majority of the increase in ride height when swapping out NA parts for NB parts on an NA car is mostly a function of spring length and the position of the lower perch on the shock. If you're using aftermarket springs and adjustable lower perches you can probably work around that problem reasonably easily.

Anything to worry about here?

92
Car sits at 11.5/11.75

Sending my extra set of Koni yellows to be revalved
NB top hats
Probably going to end up with ground control sleeves

Thinking
700 F 5"
450 R 6"

6'' front 7'' rear. a