aidandj

iTrader: (5)

Whats wrong with NA HD shocks and NB top hats? Would probably make it so you didn't need extended tophats.

7" springs is going to make getting to 12 in the front hard. Go 6" in front, 7" in the rear. Thats how most of us like it.

sixshooter

iTrader: (12)

NA HD is not as good as Hard S. And don't believe everything you read on M.net. People are much quicker to call "BS" when they see BS here than over there. If you read this thread you've probably seen the chart with the damping rates of the NA HD and the Hard S and have seen the empirical difference.

You can use the ISC fronts if you want, but they aren't as necessary.

zellers88

iTrader: (1)

Correct, NA HD's give you the most travel. FCM has a kit as well as Advanced Autosports to fit the NB top hats.

CHUNKYBOWSER

Yes, I was just looking at the charts. As much as I would like more travel with the NA HDs, I don't want to sacrifice the damping ability for the springs I've chosen.

Looks like I'll be going with this:

Hard S Shocks
front 6" 500lb and rear 7" 350lb
Advanced autosport collars
NB front tophats
ISC rear 1.5" tophats

Hopefully that will get me low enough and outperform my Vmaxx sports. On my old Miata I had Tein Street Flex coilovers with 500/330lb spring rates and I enjoyed those much more, seemed like the perfect setup.

edmcguirk

How tall are those springs?

WMP

iTrader: (1)

Here's my car with basically the same setup minus the ISC top hats in the rear. As long as you're running the Advanced Autosports sleeves you shouldn't have a problem with getting low.

stefanst

iTrader: (1)

6.0 inch rear, 6.5 front. I don't think they'll bind, but you will have a fairly good-sized rattle-gap at these spring rates, if you're not running helpers. I'd say about 1.5" gap front and a little less, maybe 1" rear.

zellers88

iTrader: (1)

I have the opposite, more gap in the rear, less in the front. That's with about 1/4" rake.

edmcguirk

As long as they're not 5 or 4 inch springs.

They're not quite the rates I'm looking for but the Amazon kit I quoted earlier is supposed to have 4 350 pound springs for just slightly more.

I have to decide if I want one good spring rate and buy a second pair or have all four springs that are a little off from what I want.

I was thinking 450/350 but I might accept 500/300.

stefanst

iTrader: (1)

And remember: These springrates are *estimates* based on me measuring coil-wire thickness (which includes an estimate for coating thickness) and counting number of coils and then plugging all of that into a random online calculator.

sixshooter

iTrader: (12)

I like 7 inch springs for less than 550lbs/in.

x_25

I am running 7" front and rear at 450/350. Had no problem getting the car down to 3.75"/4" pinch weld height, but that was on Koni Sports. (since raised up, I autocrossed on a smooth lot, so played the dirty trick of just sitting it on it's bump stops for that.)

sixshooter

iTrader: (12)

The longer springs give less chance of binding and the added benefit of better droop travel.

deezums

iTrader: (3)

Longer springs of the same rating don't give more droop travel. A car of a fixed weight will only compress a fixed rate spring a certain amount. Doesn't matter if it's a 5" 500# spring or a 10" 500# spring, they both compress the same amount under the same weight and therefore have the same amount of droop travel. Only way to get more droop travel is helper springs, or softer main springs.

acedeuce802

iTrader: (1)

Yep, spring length doesn't matter at all and will not change the dynamics at all unless you are coil binding or ride height is out of collar adjustment range with the given spring length.

edmcguirk

Yes, but ride height and coil bind are exactly the important considerations that make your spring length choices.

Short spring and you risk coil bind, long spring and you risk monster truck ride height.

stefanst

iTrader: (1)

No. Spring length has nothing to do with ride height. This has been explained in this thread about 100 times.

edmcguirk

Sure, as long as you can keep the spring within the shock's adjustment range. But just because you can compensate for spring length does not mean that spring length is not important.

I don't know if anyone in this thread has made the proper measurements and calculations to know which springs will end up outside of the adjustment range but I know that an 8 inch spring will be good at a lower spring rate. At some point a stiffer spring with an 8 inch length will be too long to adjust down to stock ride height. At that point, spring length does affect ride height.

At least to within half an inch we should know:

The extended distance of a Bilstein shock from the circlip to the spring seat.
The compressed shock length at stock ride height with stock tophats.
The fully compressed length of a Bilstein shock.
The motion ratio of a Miata suspension.
The approximate weight on a corner of a stock Miata.

We could then adjust it based on whether we want lower than stock ride height, spring barrels that overlap the circlip, different tophats, which Bilstein shock body is in use, NA or NB Miata, etc.


From all that we should be able to calculate what springs have a danger of being too long or too short.

I don't have those measurements but a spreadsheet that could do all that would be nice. I'd be happy with just a spreadsheet of all those measurements. Give me those measurements and I could produce a table of all possible Miata coilover spring lengths that can be adjusted to stock ride height and have coil bind only beyond a fully compressed shock and which ones could benefit from tender springs because they will be too short at full extension. (given that all steel 2.5 inch linear springs will have similar specs)

2manyhobyz

iTrader: (4)

Ok, parts are here. I purchased the Energy Suspension coil spring isolators and the Ride Tech Delrin spring washers. You can't really run both cause the isolators really fit tight over the sleeves so they will inhibit the delrin from minimizing coil bind.
So which of these would you choose and why?
Front- Eibach 600
Rear- QA1 400
Thanks,
-Jeff

itskv

Anyone here with a NA using MSM billies?

I am having some issues with my setup. over normal roads they're fine and noise free. Once I run over a hump or pothole at typical residential speeds or even on the highway, I get a very loud metal to metal bang noise. I've inspected my suspension areas and don't see any noticeable indications of contact.

My setup is:
NA chassis
MSM BILLIES
TWO-SIX Racing tophats
ES bushings for lower and upper shock mount
Speedthane bumps cut to 36mm (maybe this is the issue?)
rear sleeves are cut .75" off the top
6" F 600lb 7" R 400lb.

Ride height is currently 12.5" F/ 13" R hub to fender... Rear perches are at the very bottom of the sleeves already, will not go any lower than 13". Front's are about 30mm from the end of the sleeves.

I'm guessing it is the control arm contact...

Would a pot hole really "unseat" the springs with the weight of the car? Droop would only occur if the car is lifted off the ground from my understanding.