I saw this thread: http://www.sccaforums.com/forums/fo...cope/posts and it has answered some questions but I still have a few things I'm wondering about and don't see in any searches I can come up with. If there's another thread out there feel free to link me to it but my keywords aren't getting me what I want. :)

I bought a '94 Miata as a toy. I'm in my 2nd year of Solo and have always wanted a Miata so I got one before I started my second season. Right now, I have Koni Sports, Direzza Star Specs, and the Racing Beat fromt swaybar/brace hardware/endlinks. My car has a torsen diff and "B" package with power windows, and a really questionably installed keyless entry system... lol.

Anyway, what I'm getting at here is that I would like to build this car towards STR rules, but within the confines of what I've already bought. I thought I would be content with stock class but I find myself wanting a more responsive, challenging to drive, firmer car. Plus, I'm sick of whacking the bump stops on the highway... Firmer springs are required just for a fun daily driver let alone a race car.

So I come across the Koni threaded sleeves for my Sport shocks. Great! Cheap 'coilover' upgrade. However, I have seen that I'm limited to something like 450-500lb/in springs, and the cool kids all seem to be running 500-700lb/in springs (front anyway). Since I have this giant front swaybar and just a stock rear bar, I'm thinking I can help reduce the floppyness of softer springs by using a little firmer spring in the rear than if I were to run stock-balance front/rear swaybars.

I haven't driven the car on-course with the front bar yet. It went on last night but even on the street I can feel the car wants to push. I am planning on doing an alignment but I also want to start planning out my suspension so I can at least get a budget and parts list going, which will allow me to start piecing it together.

I was thinking about 450lb/in front springs so that I can over-dampen the front if I want to for some reason and something like 350lb/in for the rear, which is 1.28 front/rear rate ratio as opposed to a stock 1.58 front/rear ratio. I'm not experienced enough to know if I'll be even remotely happy with this setup or if the rear will be too firm? Or should I go ahead and shoot up to 500lb front springs and just go for whatever rear, then soften/firm up the rear depending on how the car feels?

Any other suggestions? I'm not planning on going to Nationals with the car, I am nowhere near being legitimately fast as a driver, but I would like to tweak on the car because that's how I roll.

Thoughts? Ideas? Any input is great!

Thanks!

-Eric

I ran 450/300 with stock R package Bilsteins for a year or so, not a bad setup. Read up at FatCatMotorsports and Miata.Net suspension forum. Also keep in mind that "all the cool kids" may not be street driving their Miatas, so you may need to balance spring rates vs. street driveability (if that's a concern). No, you're probably not going to go much over 500lb w/o shocks setup for the higher rate.

The monster front bar (1.25" hollow?) is a good start as well. I ran w/o the rear sway. I have a new suspension this year, so if I ever get my ECU issues sorted, I'll have to test w/ and w/o the rear sway.

Thanks! The front bar is the 1.125" hollow bar (0.125" wall) so yeah, pretty big on a Miata. :) The first time I saw one on a car I thought it was a chassis brace. Good stuff! But it feels like, on the street, that it's got a bit of understeer. Will have to see how it goes Sunday. Seems like the R-Package Bilsteins would be too soft for the higher rate but it sounds like it worked at least. Stock springs are something like 150F/100R according to research so the firmer springs on your shocks would have had to be at least a little bouncy! :)

In terms of spring rates, I think I want it as close as I can get to optimal for on-track use. I will drive it fairly often on the street but I also have a mostly stock Mazda 3 that's for the days I don't feel like driving a race car to work. :) I kinda enjoy the "raw" feeling of driving something inappropriate on the street. It's just fun for me. Maybe I haven't experienced the level of firmness I'm getting myself into but I'm not too worried about it.

If I do the Koni sleeves, they come set up for 2.25" springs. Can buy spacers for 2.5" springs but I think I'd rather try to leave it with as few pieces as possible. Eibach looks to sell 2.25" springs in about every rate imaginable. Any cheaper or even better brands out there I should look at?

I'll have to look at the rules because I don't remember what it says about upper spring perches, but if I were to buy NB rear upper spring perches, I would imagine a 1-inch longer spring would compensate for the change in height? So a 6" in the front and 7" in the rear? The lengths are still a little fuzzy to me.

Any suggestions on starting rates? Maybe 450F/350R? Or was 450/350 and no rear bar a pretty good combination? Or should I really just go 500 on the front and set the front shocks to full firm and not worry about it? I need an alignment too... Planning on buying some "DIY" equipment in the next couple weeks. :) Might order a couple sleeves and springs just to see what it all looks like also. Maybe If I piece it together it won't seem as expensive. :)

What about bump stops? :p Maybe I should start a spreadsheet and try to keep track of it all. One step at a time I'll figure it out eventually... lol

Thanks again,

-Eric

-Anywhere in the 450-500 front and 300-350 rear range will work. I'd be inclined to go with on the low end of those ranges to try to stay within the effective damping range of the Konis.

-Upgraded bumpstops will go a long way towards improving both ride and on-the-limit handling The aformentioned Fatcat Motorsports has a selection of bumpstops, as well as much information on why you want to make this change.

-Going to the NB upper mounts isn't as easy as it seems since there's not enough threading on the shaft of an NA shock to use the stock NB bushings and hardware. Again, Fatcat can help with this upgrade.

Got'cha. So maybe I should start at 450 and if it really needs more, I can either get some real coilovers down the road, re-valve, or just buy race shocks at some point.

I'll check out FatCat. Their name pops up quite a lot but the coilover setup is out of my price range for now. Maybe some day. :)

Thanks!

-Eric

If you're really budget constrained, I would consider this set-up:

Koni Threaded Sleeve Kit: http://www.summitracing.com/parts/K...000000005/
Koni 2.25"-2.5" adapter: http://www.summitracing.com/parts/KON-1529040030/
Front Springs: http://www.summitracing.com/parts/HAL-7-450/
Rear Springs: http://www.summitracing.com/parts/HAL-7-300/
Fat-Cat 36mm linear bump stop kit with 9mm spacers: http://fatcatmotorsports.com/FCM_Koni_products_NA.htm#bump

It's not the perfect set-up, but it's an 80% set-up for about 20% of the price of a top-tier coilover kit. Certainly should make the car feel much more responsive than it does in its current configuration.

You can add a FatCat NB top mount conversion for $189 (including the mounts), either now or down the road.

You can always revalve the Konis for more spring rate later.

I know you'd prefer to keep the 2.25" springs, but its not worth the $140 extra if money is tight. Again, that's something you can do down the road.

Does the "Threaded Sleeve Kit" come with the lower perches also? I thought that was just part of what I needed so the Ground Control setup was starting to look cheaper... lol.

Will have to add it all up after work. :)

Thanks!

-Eric

Good catch. Jegs has the sleeves for much less as well as the perches:

http://www.jegs.com/i/Koni/610/... ($15.99)

http://www.jegs.com/i/Koni/610/30.0000.0006/10002/-1?parentProductId= ($19.99 & no need for seperate 2.25" -> 2.5" adapter)

In the end, you come in about the same as a Ground Control kit, but that kid does not include bump stops.

The bad news is that I saw those as well; and they're 30-series sleeves. I'm pretty sure I need 80-series part numbers to match my 80-series shocks from looking on Koni's product catalog.

So I really need http://www.jegs.com/i/Koni/610/80-0...5/10002/-1 and http://www.jegs.com/i/Koni/610/80-0...6/10002/-1 right?

Everyone has said the Koni sleeves are cheaper than the $400 Ground Controls, but I come up with a total of $560 for the Koni setup without bump stops. Just 4 springs, sleeves, perches, and 2.5" adapters. Either I'm doing something wrong or things have changed significantly. :)

-Eric

You're right, I've been out the miata scene a while and got the shocks confused.

Honestly, I got one of the $50 coilover kits off ebay just for the sleeves and perches. I used bicycle inner tube sections rolled around the shock tube as "bushings" to keep the sleeve concentric with the shock tube, and just had the sleeve resting on the existing spring perch. I pitched the crap springs that came with that kit and used the QA1s. The ride height was just a little higher than I wanted with KYB shocks and 7" front springs, but with Konis you can move the perch lower down and should be able to get as low as you want.

Hmm... I dunno about the eBay setups. They look like a really high potential for hit-and-miss. They don't give any kind of diameter so it'd be a crap shoot if they're too big or too small it seems like. I'm not quite THAT low on budget but am trying to figure out how to save some money if I can. :)

It's also entertaining that they say "approximately" 300 pound springs; but it's 15-20% firmer than stock. Isn't that more like ... 200-300% firmer? Just an observation. :)

-Eric

I had a set of eBay sleeves/perches, and they worked great (two yeatrs of autoX and DD'ing on some pretty rough roads). Same as gary p, I just ditched the springs. The set I bought (~$20, IIRC) came with an assortment of o-rings to use between the shocks and the sleeves.

I ended up springing for the FatCat stops and top mounts, which seemed to really help with reducing the effect of hitting the stops. You can save some money by adapting the NB mounts yourself, but the FC bits are a nice easy button.

IIRC, my setup was:
-1.25" hollow bar
-Heim-joint front adjustable endlinks (949, I think)
-ebay sleeves
-450f/325r springs (pretty sur eon those numbers, but in that ballpark. I don't remember the lengths, but 7"f/6"r sounds right)
-OTS Koni sports
-FC stops and top mounts
-No rear bar except on really small courses. On higher-speed runway courses, hooking up the stock rear bar made it really loose.

I think all in, I was under $1000. Might not have been a "national champion" setup, but I'm not a National-champion driver anyway. But it worked really well on course and was entirely liveable on the street, even if my wife disagreed with that opinion.

Now you've got me thinking about the eBay setups... Is there any chance they'll be too small for the Konis or are they just likely too big?

Although I guess, for 50 bucks, it won't hurt too awful bad if they don't fit. Can always craigslist 'em :p I'll need the springs regardless so it's probably worth the risk. If they don't work out, order Koni kits and be done with it. Maybe I'll order a set and give it a shot. As far as springs go, I kinda would like it a little looser than it is now. It feels like the front goes out before the rear no matter what I do, which is too confidence-inspiring and hard for me to tell where the limit is. I tend to under-drive because I don't like scrubbing off front tires. If it's a little loose (or closer to neutral), I feel like I will know where the limit is more intuitively. I think I'm going to try 450/350 (maybe 325) with the stock rear bar and see where it gets me. If it needs more roll/dive stiffness or just is too squirrely, I can bump the fronts up to 500. :)

I also wonder if I can get the same length springs front and rear? My Konis have a lower perch location that's about a half inch lower than the "R-Package" location, so I think I'll be alright with 7" springs all the way around. I'll probably just order some sleeves and hold off on springs to see if they'll fit before I Do anything. Then go from there.

I'm kinda thinking my best bet may just be to start stockpiling parts until winter time so I can bolt 'em on in the off season without ruining my ES undefeated streak this year so far. :p Would hate to go off and get all the upgrading done in one season, especially if I can't even seem to make the tires squeal over half the course...

There's so much driver work to be done I don't even know why I'm looking at upgrades. But it sure is fun. :)

Thanks guys. I'll let ya know what I go with.

I bought these: http://www.ebay.com/itm/MAZDA-MIATA...mp;vxp=mtr They all look the same and they were the cheapest. My shocks measure to 42.2mm on my calipers, and another set of these showed about 48mm on a scale (just eyeballing the ruler in the photo) but they come with 16 o-rings for spacers... I'm sure it'll work just fine. Might have to use the Koni lower spring perch rather than just the snap ring but oh well. Doing it ghetto style. :p

Next step is some cheap springs, bumpstops and upper perches... Going to wait 'til they get here and measure/test-fit everything first though.

Thanks guys. :)

-Eric

That looks a lot like the one I bought (except my springs were red)...came with the wrenches and a bag 'o o-rings.

Well the coilover sleeves came in. They look perfectly fine!

Now to pick out springs.. lol. I'm probably going to get the FCM tophats and bump stops; Should I go for 7 inch springs or 6 inch springs? I'd like to stick with the same front and rear so that I can swap my 450s to the rear when I go buy 700s and real coilovers later on... haha. Trying to plan for the future here. :p

It's almost tempting to just put the setup on the car as-is just for grins, but I know it'll never be as good as known rates. Just a waste of time at that point. :)

-Eric

6" should be fine.

Is there any reason not to go with 7" springs though? The cheapest springs I can find are on soloperformance (dot com) and are only 7" and longer. They don't appear to carry a 6" spring. I can pull about half an inch out of each end on my Konis compared with current, and about an inch compared to a "stock" perch height. The springs that came with my coilover sleeves are 7.25" in length (but presumably pretty soft).

I'm also planning to get the FCM upper mounts and 36mm bump stops which should make the spring need to be a little longer than if I was leaving everything stock up top, correct?

I should probably make sure the FCM upper mounts are STR legal before I go buying them though... I haven't actually checked! hah

Thanks again for all the help guys!

-Eric

I went ahead and ordered some 7" Summit Racing 450lb and 325lb springs... $31.99 each. $138 with shipping... So far I'm only $183 into what looked like a $700 adventure. :)

All that's left after those show up is to get the FCM upper mounts.

-Eric

I installed the sleeves/springs over the weekend. 7" really is as long as possible on my setup. With the FCM upper mounts I should be able to get a good ride height without being half an inch from the bump stops. :)

It's stiff! I am not sure if it's stiff because it's all over the bumpstops or if that's just how it is, but it's stiff! I like it. I just wish there was a good way to make sure I wasn't riding the bump stops. I may go run the ride height up 2 turns on each side before Sunday so that I can feel the difference. I'll definitely be ordering FCM parts after the weekend though.

-Eric

put an o-ring or a zip tie on the bottom of the shock shaft, then see where it ends up. If it ends up butted up against the bump stop, slide it back down then try taking lesser turns, and see if it still ends up butted up against the shock shaft. That'll tell you how hard of a turn will put you into the bumpstops.