Lowering Springs

Discussions relating to MX5 Tyre choice, Wheels, Brakes Suspension components and other items to keep you going around corners, stuck to the ground or stopping on a dime.

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evel
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Lowering Springs

Post by evel » Mon Dec 17, 2012 7:17 pm

Im kinda keen on giving my mx5 a little bit of a drop, but im too stingey to go and buy coilovers just yet. Im thinking about lowering springs but I dont want to lose my nice stiff uncomfortable suspension, so whats the best brand to go with that will still give me about the same sort of handling as the stock bilstein suspension?
'94 S-Special 1800 in BLACK
Flares and 225/45 Semi Slicks.

warrior
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Post by warrior » Mon Dec 17, 2012 8:05 pm

I run dobies in both my MX5 and MR2 and cant say enough about them, they give a nice drop, handle well and have a very good ride. You are welcome to come for a ride in my car if you want to feel how they handle.
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Post by WideOpenThrottle » Mon Dec 17, 2012 8:20 pm

And i got Koni sports...you get 3 height settings [non-adjustable once installed] plus shock damper adjustment from soft to firm.

I got no complaints
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Post by Furai » Fri Dec 21, 2012 7:42 am

A lot of the stiffness is in the valving of your Bilsteins not the springs, I would imagine going stiffer will get closer to a good valving/spring relationship and make your ride better.

I had Bilstein HD(Softer valved) with some Tein S-Techs and the ride was firm, but now I have gone for 8kg and 6kg springs(Funnily enough the rides better because they were revalved to match) .

Which reminds me I need to sell the Tein S-Techs ($200 :lol: )

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Post by tomtikki » Fri Dec 21, 2012 9:18 am

Furai wrote: Which reminds me I need to sell the Tein S-Techs ($200 :lol: )
Oh come on!! I just bought a set! Ah well, fitted now. My factory springs must have sagged a bit coz they havn't dropped the car much. I'm hoping they will settle some more.
Happy with them though, car feels great but not harsh. -I'm on factory kyb's all round.
I'm not crazy, my mother had me tested.

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Post by siren676 » Fri Dec 21, 2012 10:08 am

Sounds a bit like what mine did with those springs. Did it only lower it 20mm or so?
1990 NA6C MX5

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Post by tomtikki » Fri Dec 21, 2012 11:11 am

Yeah I got 25mm off the back and only 10mm off the front -perhaps different top hats for the front...
Im real happy with the ride though, I've had lowered springs before and they felt a little soft.
I'm not crazy, my mother had me tested.

evel
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Post by evel » Fri Dec 21, 2012 6:52 pm

Mr Furai, do you have any pictures with the S-Techs in?
'94 S-Special 1800 in BLACK
Flares and 225/45 Semi Slicks.

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Post by Furai » Sat Dec 22, 2012 12:48 pm

Image

Image

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Post by MrGrey » Mon Sep 16, 2013 5:50 pm

-=THREAD RESURRECTION=-


I figured I would post here instead of starting yet another "lowering springs thread" (there's a few already) :wink:

Anyhow, I am sick of my '5 having the ride height of a Hilux so when Built4speed posted some 2nd hand springs for sale, I jumped at them (figuratively, not literally) ... which leads me to a few questions :)

1) are there any bits I should look at while I am doing this? eg should I replace the rubber bump-stops while I am at it? (I *think* that's what they are called). apart from the springs themselves, are there any perishable bits I should replace while I have that section in bits?

2) does anyone have a set of spring compressors I would be able to borrow? purchasing 2 of them for around $40 each is a fair bit of cash considering I would (most likely) only use them once. I would be happy to pay track & trace courier fees to get them sent up and to return them. I know this is a bit of an ask considering only a few of you have met me in person, but I can assure you I am not a dodgy person and would look after them and return them with great care. I am happy to give any details requested to any potential loaner to show I am not some random stranger hiding on the internet.

3) does anyone have any suggestions, tips or things to look out for whiles undertaking this job? I have been researching it a fair bit on the net, but any personal experiences or tips would be appreciated.

Thanks for your time and consideration :)

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Post by warrior » Mon Sep 16, 2013 6:27 pm

Replace the bumpstops with a good set (not standard) I have some spring compressors you could borrow but I am in Auckland.
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Post by MrGrey » Mon Sep 16, 2013 6:35 pm

any particular type of bump-stop I should go for?
and how hard are they to replace?

thanks for your time :)

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Post by siren676 » Mon Sep 16, 2013 6:53 pm

Bump stops simply slide over the shock shaft, takes maybe 10 secs while the springs are off. You will have a bit of fun getting the struts out if you've never done them before, set yourself a whole day to do it just in case.
1990 NA6C MX5

warrior
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Post by warrior » Mon Sep 16, 2013 7:19 pm

I got some from STOCKS in Auckland, they make a big improvement. And once you lower an mx5 it will hit the bumpstops so they need to be good. Are you in Northland?
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Post by marcellarius » Mon Sep 16, 2013 7:24 pm

If my memory serves, if you use anything but an unmodified OE bumpstop then you'll need LVV certification. And the car has to be clear of the bumpstops when fully laden.

You may get through WOFs with a different bumpstop if it doesn't look suspicious, especially if you have a boot installed over it.

The NA factory bumpstops are pretty big, and designed so that the car compresses onto them when cornering, increasing the effective spring rate.

In most street suspension setups, you're going to be compressing the bumpstop in corners, so the spring rate and linearity of the bump stop will have an impact on the way the car handles. If the car is hitting the bumpstops too hard, the sudden change in wheel rate may cause unpredictable handling.

Check out http://fatcatmotorsports.com/FCM_app_gu ... #Bumpstops. They sell a variety of bumpstops and have lots of interesting suspension-related infos.

Image

Some info on the standard NA bump stops (comparisons between NA6 and NA8, and butchering advice)
http://www.virkki.com/jyri/miata/bumps.html

warrior
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Post by warrior » Mon Sep 16, 2013 7:26 pm

I have never heard of anyone not getting a WOF for non oem bumpstops. They will be fine
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Post by MrGrey » Mon Sep 16, 2013 7:33 pm

Thank you for all the information guys :)
is there a specific part number for the bumpstops? or should I just ask for bumpstops for a 1990 na6 mx5 and hope they get the right ones?

and Warrior, I live in Whangarei.

warrior
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Post by warrior » Mon Sep 16, 2013 7:40 pm

They will need to know the shaft size of the shocks (they may know already) but a lot of bumpstops are universal. I sure if you tell them what you want it for they will be able to help you.

I did shorten mine a bit as I thought they were a bit long because with lowered springs you wont need them as long as standard because there wont be as much travel.

I am happy to send you my spring compressors if you pay for postage.

PM me.
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Post by MrGrey » Mon Sep 16, 2013 7:42 pm

thank you warrior, you are a scholar and a gentleman :)

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Post by marcellarius » Mon Sep 16, 2013 9:18 pm

If I were in your position, I'd do further research and consider whether it's worth dropping the money on a set designed for the MX5 and your particular uses.

I'd be cautious chopping up bumpstops though... without knowing the force vs. compression behaviour of them, you might compromise the performance or protection they provide.
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Post by marcellarius » Mon Sep 16, 2013 9:20 pm

Spring compressors: I borrowed a set of Repco spring compressors off a mate, but they were completely useless for the small springs used on the MX5... I guess they were designed with Falcons and Commodores in mind.

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Post by siren676 » Mon Sep 16, 2013 9:44 pm

^this
I have some twin prong "death stick" spring compressors i got off trademe, i could get 1 prong on the coil and the other one partially on, just enough to keep it seated while compressing the springs. It was a nail biting experience especially with the amount of preload on the stock springs
1990 NA6C MX5

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Post by MrGrey » Tue Sep 17, 2013 4:57 pm

I phoned the 4 local shock absorber outlets here wanting to know about which specific bump stops i needed, and they all gave the same answer:

"nah mate, they don't do vehicle specific ones anymore, you just get a universal one"

The only fussy bit with them is they need a snug fit on the shaft, so does anyone know offhand the diameter of the shaft in a set of stock MX5 springs?

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Post by marcellarius » Tue Sep 17, 2013 5:23 pm

As it happens I have a set of NA8C struts and a vernier caliper in the garage.

Shaft is 12.5mm (front and rear).

Top of shock is about 50mm

Spring inner diameter is at least 70mm (kind of harder to measure with that tool but could be useful)

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Post by Furai » Tue Sep 17, 2013 5:32 pm

marcellarius wrote:As it happens I have a set of NA8C struts and a vernier caliper in the garage.

Shaft is 12.5mm (front and rear).

Top of shock is about 50mm

Spring inner diameter is at least 70mm (kind of harder to measure with that tool but could be useful)
ID of stock springs I measured 80mm on my NA6 stock and Tein ones :wink:

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