Yeah, but with bigger springs I can drive like a bigger man!

 

Are you running at least a 1in (25mm) sway bar in front ? Start there before adding more spring if you haven't already.

 

Good point- the '99 has a 1.125 tubular front bar and the '03 is stock. Both run 55/350 Bilstein setups and both have the same problem. Both are heavy pigs though. Me included
One behavior I noticed was that in a fast, long, full-throttle 3rd gear turn the outside (driver's side) suspension is essentially already fully loaded. Any slight bump in the surface and things stop being fun.

 

Yes, you need enough spring rate (or travel) to keep you off of the bumpstops at maximum sustained grip for your chosen tire. Sways "borrow" spring rate from the other side of the car and therefore don't necessitate as strong a spring.

Additional travel will help because a 500lb per inch spring with 1 inch of available travel will only support 500lbs before contacting the bumpstop. But if you have 2 inches of available travel with the same 500lb spring then it will support 1000lbs of force before contacting the bumpstop. Travel is important to the equation.

I was originally confronted with this issue when running at Road Atlanta. Turn 12 is a very fast, wide sweeper at the bottom of a large hill. There is raised curbing on the outside edge of the surface at track out. If the car is already on or near the bumpstops on the outside and you contact the curbing there is no suspension travel left to keep the car from unsettling. There are concrete walls on both sides of the surface with very little room for error.

 

Great thread, really like the DIY attitude of it. It seems everyone so far is running NA or NB shocks, has anyone tried this method on NC shocks at all? I'd quite to give it a go as I'm looking to get my NC a little more track focused so I'm avoiding the lowering springs route.

Anyway I've measured Bilsteins and they are the same diameter (around 50mm), so the coilover adaptor should work.

The only problem is that the rear top hat on the NC is a totally different design, here's a pic:



The spring is tapered, it's wider at the top hat, and this so far seems to be the main issue.

Could I get some sort of bush or adaptor in order to make a straight spring fit?

Once I find the spring clamps I'll get the shock apart and take some measurements.

 

Having never looked at a NC setup, my first inclination is to pull the black spring perch off and see if enough of the perch is available for the 2.5" spring to sit on. If not then your only option is to machine a locating bushing.

 

Ok thanks, once I find my spring compressor I'll get it apart and see how it lines up with a 2.5" spring. I guess I could make a bush out of a helper spring adaptor if needed.

 

Doesnt goodwin sell a perch to put 2.5" springs on the NC tophat?

 

Thanks, found them:

RX8/ NC Miata Upper Spring Perch Delrin for RACE Springs for RX8

It's a shame Goodwin don't post to the UK, I'll have to see if I can use a forwarding service, or I may be able to fabricate something myself

 

hey guys, could some of you measure the Outside diameter of the ALL star performace sleeve? Also it would help me a lot if you could measure "adjusting nut" diameter for smallest possible to fit spring. So you need to measure the step which is on that sleeve.
See my pro drawing to see what I want to measure. :-D
https://www.miataturbo.net/attachmen...1&d=1479574061

 

Sleeve OD: 2.352" [59.74]

Spring collar minimum ID: 2.470" [62.74] (which is why they call for 2-1/2" springs)

 

Dumb but quick question: I have 7 inch mains all around (550/400) and only a pair of 100lb helpers.

Do I:
1. Say **** it to the helpers
2. Put the helpers in the front or the back (which??)
3. Man up and buy another pair

 

7 inch are probably long enough you won't have room for helpers, depending upon your ride height. I couldn't fit them and I'm not low.

 

Got it. Thanks. How long of main springs do people get with tenders? The tenders themselves are pretty long (3-4in), but I gusee that doesn't really matter since precompress quite a bit?

 

Some shocks have more travel than others. You can likely do it with 6" on the Bilsteins.

 

I had about 1.25" of loose droop travel with 7" 550/350 springs and 10AE billies on my NA, but I wasn't all that low.

Helpers with a block height less than an inch should have fit my setup fine. It likely would have required a spring compressor to assemble, though.

 

Damnit, I just realized I didn't buy the perch adjustment tool.... Which one fits for the Advanced 4 inch kit?

 

This one: https://www.advanced-autosports.com/...ts/wrench-long

or this one: https://www.advanced-autosports.com/...s/wrench-short

There may be others for less.

 

Quick question. In the rear I have pretty much zero room between the control arm and frame of the car. If I lower my car a bit more to get closer to the 949 ride heights, I will probably start contacting things right?

For reference I am running a 7" 300 lbs/in spring with ISC 1.5" extended rear top hat and a 225/45/15 tire. My bumpstop is already trimmed to the minimum length. I believe the rears are set to 12.75" hub to fender but I'll get a pinch weld measurement when there's light out.

 

This has been hashed out repeatedly over the last 49 pages...if you have sized/trimmed your bumpstops to have maximum travel WITHOUT contacting anything at full compression, then lowering the spring perch will not change that. You will just reduce your compression travel. You will be on your bumpstops more often, but if you can fully compress without contact, that will not change (unless you change bumpstops or tophats). If you have "pretty much zero" clearance, there is still some chance that a large enough impact will compress the bumpstop that little bit more than you can simulate with your floor jack, allowing frame contact...to be safe, you would go with longer bumpstops or a spacer above the stop.