I looked at the Summit springs but it looks like the shortest length they offer is 7", and I think for NA's most people were recommending 7" front and 6" back, no?

Actually, at the moment it doesn't look like Summit is stocking the lengths/weights I need anyway. The only 6" spring is 900lbs.

 

I'd need to read up but if you're using NB top hats or extended top hats why would you use the shorter?

 

Just based on reports from the long Bilstein threads on all the forums. Seems like for NB's, 7"/7" was fine, but for NA's, using MSM shocks meant 7"/6" springs, and either extended tophats in the rear, or cutting a new circlip groove 1" or 1.5" lower on the shock body.

Road quality around here dictates a priority on comfort, so I'm aiming for stock R-package height or just a touch lower.

 

No. I'm running 7in all around with plenty of adjustment room to go up or down.
Summit Racing 550/350 here.

 

On which shocks?

Summit springs are on sale right now...$26.50 each for certain rates.

Summit Racing 7" 550lbs -- $26.50

and then either

Summit Racing 7" 350lbs -- $34.97
or
QA1 High Travel 7" 350 lbs -- $37.97

Any reason to pick QA1 over Summit for the rears? Just save the $6 and go Summit all around?


Also -- if I ordered the Two Six extended top hats for the rears, then I wouldn't need any isolators, correct? They have them built in. My only concern is that they only add 3/4", not 1" or 2" like other extended top hats on the market. Is 3/4" enough?

http://www.twosixmotorsports.com/sto...&product_id=51

 

Bilstein Hard S
Extended hats

 

No real reason to go QA1 over Summit. They're probably the same thing.

7" is fine. I've seen the Two Six units a few times, i'm probably responsible for half of their sales at this point. Good pieces. Do those.

3/4" is enough.

I would STILL suggest moving the circlips down. With the Allstar sleeves, you're going to have the top of the sleeve above the top of the shock. You can cut the sleeve, but cutting new grooves yields more advantages in adjustability.

Yes, you do want to move the groove down AND run extended hats.

You should be able to get 12" hub to fender quite easily with 7" springs and this setup, if you cut new grooves.

 

Was planning on spending a bit more for the Advanced Autosport 4" sleeves to avoid the need to cut them, so that solves that problem.

Would like to avoid cutting new circlip grooves as I don't have a good machine shop nearby. Last time I needed something done it ended up being a 2 hour hassle and $60 just to have them cut down a spring perch by 1/8".

 

Ah ok, that works too. Worst case scenario you want to move them down later, but no sense in spending the money on a broke-*** suspension until you know you NEED to.

 

Sorry, one more question -- I'll still need one pair of isolators for the fronts, right? The NB tophats won't fit snugly on the 2.5" springs.

 

"Need" is relative. I thought factory isolators were close enough. I run Energy Suspension isolators on the front of mine, but i have extended hats on all four corners and the pipe that was welded in holds the isolators perfectly.

 

Excellent. Ordered the isolators just in case...if I don't need them it was only $8.



Still to be ordered: Advanced Autosport sleeves and Two Six extended hats. Should come out to under $700 minus whatever I can sell the Eibach springs for.

 

I'm running 7 inch 550 front and 7 inch 350 rear on NA shocks. The Spec Miata 700# Eibachs are 6 inches for the front.

 

Yay.

 

LOL miata folk have puked on them since the beginning.

While stiff springs will reduce bottoming, having that little compression damping sucks hairy sweaty *****.

And springs don't "absorb the energy on compression events". They store, then release them by re-extending, during which the rebound damping absorbs the energy. So far so good... but then think. If the springs need to extend abruptly, the springs store the energy, then release them by re-compressing to their original length, during which, the non-existent bump damping does *not* absorb any energy, so the spring overshoots, and has to rebound to be absorbed. Now you see you have excess body motion, because of insufficient bump damping. Not good. Then... with insufficient bump damping, you need extra rebound damping, to reduce oscillations. With extra rebound damping, when the spring needs to abruptly extend to accommodate a dip in the road, this extra rebound damping will impart more motion into the chassis (downward in this case).

FAIL.

Much better to have the right amount of low speed rebound *and* bump damping... not too little of one, compensating by putting too much of the other.