RoadsterSport NC ClubSport Coilovers

DESCRIPTION

This custom combo incorporates our new NC Koni Race height-adjustable threaded body shocks and a special dual-rate spring developed specifically for this package and made for us by Progress Technology. The result is a shorter shock body extra long travel coilover that boasts premium quality from some of the best names in suspension, with an unbeatable price tag.

This kit is all about MAXIMUM performance to dollar ratio with way above average ride quality for these spring rates. Massive 136mm front stroke and 186mm rear stroke is more than anything we have seen on this platform. We focused the costs and R&D where it all matters, and avoided anything unnecessary in order to create the new best bargain among coilover options for cars bridging the gap between fun canyon carver and occasional autocross or track fun.

To that end, we chose to design this combo to use the factory top hats, which saves the cost of manufacturing four new hats. The reason most coilovers need their own hats is that standard 2.5 inch diameter race springs used on most coilovers don't seat properly on a stock hat. Rather than go with off-the-shelf 2.5 inch race springs we decided to custom design unique coilover springs made to work with NC top hats above and a threaded body coilover perch at bottom. Retaining stock top hats also keeps the factory rubber donut mounting of those hats which cuts a lot of noise and vibration as compared with other brands using spherical bearing top hats.

Thus, instead of a universal linear 2.5 inch diameter spring, these custom springs were developed with the appropriate size at the top to fit into the factory hats. That means no extra adapters needed and the spring tapers down to a smaller diameter at the bottom to fit the adjustable perch on the special threaded body KONI Race shock. Furthermore, this custom spring incorporates two spring rates with a progressive transition, effectively having a higher primary spring rate and a lower helper spring rate all built in one spring (more on this below in the spring section). This simplification of the spring stack gets you the value of a high end coilover with dual spring setup, all incorporated into a single spring for easy assembly with less parts, and a lower price tag. AND we found in testing that this special dual-rate spring actually gives better ride quality than even a super high quality dual spring setup from Swift of similar spring rates. That's due to the special dual rate spring having a smooth progressive transition between the two portions of the spring, in stark contrast to a classic two-spring race setup where there's a sudden change in rate between the helper and main spring.

Koni Long Stroke Race Shocks

Back in the day our friends at KONI did a motorsports Koni Race valving setup for the NC for GrandAm Racing. They sent us a set of those in fixed length with that valving for testing and we LOVED IT. We loved it because it rode amazing and yet it handled race sharp. But we wanted even more - we wanted it in a height adjustable shock body in addition to the magic damping and the adjustable damping feature of the first test set sent to us. And the result is what you see here. A ride height adjustable and rebound adjustable Koni Race shock for the NC. Massive 136mm front stroke and 186mm rear stroke is more than anything we have seen on this platform. Think of it as a massively upgraded version of the popular Koni Sport shocks, adding superior damping control and fine height adjustment and extra travel. These are exclusive to Goodwin Racing.

The shock bodies feature a beautiful "chrome" finish that has undergone rigorous 1000-hour salt spray testing for exceptional corrosion protection.

These shocks come with Koni racing bumpstops included in the boxes which were selected for this kit after extensive testing in our own 2008 NC Miata. Shock rebound adjustment is done just like Koni Sport shocks via a knob at the top of the shock.

Custom Progress Dual-Rate Springs

Developed specifically for this kit, these dual-rate springs are a two-in-one wonder that operates like a traditional (and more complex) multi-spring stack found on dedicated race coilovers.

You'll often see high-end coilovers with multiple springs per shock; a main spring and a helper spring. This is particularly necessary for coilovers with higher spring rates so that as you move the lower spring perch to adjust ride height you aren't trying to compress the strong main spring further and further. The "helper" spring is a lighter secondary spring that is relatively easy to compress. The usual helper spring maintains pressure on the lower perch as you move the lower perch up or down on the shock while presenting minimal resistance to you as you make adjustments. The helper spring also helps with traction over bumps through a corner on the unloaded side of the car.

We rolled the helper and main spring into one spring by working with Progress Technology to develop a special spring that has both a main rate portion and a lower helper rate portion. Having this all incorporated in one spring eliminates the complexity of needing adapters and bearings between multiple springs. Some coilovers need up to 7 individual parts to make up one spring stack on a shock! Here you have just one spring and no potential noise sources that traditional multi-spring stacks can suffer.

Prime Section Spring rates: Front 390 lb/in, Rear 225 lb/in, roughly THREE TIMES the stock spring rates.

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Picture below is the final test set that we ran in our own NC, assembled with factory top hats. Note that, as always with NC, because it has the rubber bushings in the control arms it tends to lock height and car won't lower until you free those bushings to move. Thus, expect as normal with any NC coilover install that it will settle significantly as the bushings adjust to the new heights.

BRIAN'S NOTES

This thing now rides nearly as good as our famous OHLINS Coilovers. The damping profile in this setup is derived from shaker table work Koni did on the NC chassis for GrandAm Racing. It has the control now to work as a really nice sport touring setup that is much faster than any lowering springs with Koni SPORT shocks, and customers get precise height control of real coilovers, and the Koni Race shock damping control adjustment goes far beyond what is in the Koni Sport shocks. This is not a hardcore race setup by any means, and so much travel this is not the setup for those wanting to run really wide wheel and tire combos. Our much stiffer sprung MeisterR Club Race that come with 10kg/6kg springs, or our Feal 441 Road Race that come with 12kg/7kg, will leave this softer setup far behind on track and autocross days if lap time is your top priority. This unique combo provides a super fun and fast sport touring setup that rides better than those setups for super competent back roads fun, daily hooligan driving, and faster track and autocross work than you will get with standard lowering springs and Koni Sport shocks.

Thus, my recommendation for those interested in KONI but wanting a ton more performance than available with any NC lowering springs on Koni Sport Shocks is use this setup. Spring rates on these are the same as our standard Ohlins Coilovers, 7kg Front and 4kg Rear. In pounds that is 390 front/225 rear. In comparison, standard Progress Lowering Springs are more rate than stock but just 126 lbs/in front and 116 lbs/inch rear. So here we have more than doubled spring rates from the standard Progress Springs, yet delivered similar ride to that setup with MUCH more performance yet softer ride for daily use than something like our MeisterR ClubRace or FEAL 441.

As usual we set heights to our recommendation for NC coilover customers, which is 13.25 inches front center of wheel up to fender lip, 13.5 center of wheel rear up to rear fender lip - as shown in picture below. Since this is a real coilover customers can go lower or higher from here but we encourage customers to start with the sweet spot we designed into this setup, 13.25 inches front and 13.5 inches rear and that's what you see on our test NC here.

Brian's Tips For Setting Heights:
You jack up each corner of the car properly from the pinch welds and remove the wheels and spin the perches up until you get the height goals you want. This typically takes a few rounds of this process at each corner to get the feel of how much change in perch position results in how much resulting height change for that corner. On my 2007 with the same coilover I started with roughly 1.5 inches of thread showing at the bottom of coilovers in front and a little less in the rear. But after some driving including a track day the suspension bushings released a bit more and allowed the car to settle some and so we adjusted the heights up to get back to that desired 13.25-13.5" ride height. Final spring perch positions today are 2" of thread below the lock collar at the front and 1.5" of thread below the collar at the rear, so that is what we will recommend as a starting position. Do not expect the left and right sides to need the same amount of spinning up of the spring perch, the car does not have the same weight at each corner so don't get too locked into where the perches are, just watch the resulting heights. So, if the goals are 13.25 and 13.5 like I have on this car here, adjust each corner up until you get there.

Suggested starting perch height on the shock, from the bottom of the locking ring to the bottom of the threads: 2" front, 1.5" rear. This may result in slightly higher ride heights at first but should settle to where we like the car after some time.

At the price we can offer this setup I really think not much will come close to the combo of both quality ride and handling and performance. If you want your NC Miata to feel like a quality high speed GT, like a Jag F Type in competence and ride quality but a lot less heavy, this is the way. We have decided to call it our Club Sport Setup, it's the budget road and track coilover for those that don't have the budget for our Ohlins. Not as fast as our MeisterR ClubRace or FEAL 441 Road Race, but this long stroke setup rides real world busted up roads much better than those coilovers, and is far faster than stock setup or any standard lowering spring setup. Long Stroke Setup: 136mm front and 186mm rear, that is more travel than any competing setup we have seen.

Long stroke design also means more travel than most can ever reasonably use if much beyond stock wheel/tire sizes. We have tuned it for street use with 235/40 tires on 17x8 Hypergram wheels and relatively aggressive higher durometer bumpstops that are relatively tall (55m long rear and 45mm long front). Customers with much bigger than stock wheels and tires, and those going to tracks with big drops like Laguna Seca Raceway, should have some packers ready to clip on as needed, depending on the track. For example, we fully expect to clip in some tall packers for the Corkscrew at Laguna Seca!

Brian's Sway Bar TIP: We STRONGLY SUGGEST you don't rush into adding sway bars with this setup until you really have weeks or even months to drive it. Why? As a Koni Race shock the compression damping is enough that most will find they do NOT need sway bar upgrades for really flat handling when used with a reasonable wheel and tire package. Adding bigger sway bars will cut ride quality! These reduce body roll so much that most will not feel the need to change from OEM sways. Most of our testing of this setup was done with our Hypergram 17x8 and 235/40 Dunlop ZIII tires and we love that combo with this setup and stock sway bars. That's enough wheel and tire to be fast in the canyons and yet total grip is reasonable enough that I can flat drift it around freeway 270 degree ramps with a big smile on my face.

I also suggest that street customers start with these adjusted FULL SOFT because with roots in a KONI GrandAm Race development these have plenty of compression side damping at full soft for most street use. Dial them stiffer for track and autocross depending on surface conditions and desired balance front to rear.

KONI RACE SHOCK DYNO for the Front Shock.

GREG'S IMPRESSIONS:

If you want a proper sports car suspension, this is the answer. On surface streets this suspension is well-behaved over manhole covers and train tracks. It took the expansion joints on the freeway nicely. It handled road imperfections as one would hope from a great street suspension. But I was really impressed at how well this setup handles at speed. On fast straights, dips and bumps were not an issue as the car remained stable and planted. But it shined even more by handling the on/off ramps great, remaining flat through both tight curves and more open sweepers. I kept thinking " I need this car" when I was driving on this suspension. This will turn an NC into a perfect GT car, smooth when cruising or driving around town, and sooo much fun in the twisties.

PICTURE OF EVERYTHING IN THE BOXES:

INSTALLATION NOTES:
- As with installation of any Koni shocks in NC, the factory cup-shaped washer under the top hat has a center hole sized for factory 10mm shaft, but Koni shocks have a 12mm threaded shaft. Therefore you must drill the center hole of that washer out to 12mm (1/2") so it will fit on the Koni shock.
- Koni supplies a white plastic spacer with a slot in it with each shock. These should be installed on the shock shaft, below the bumpstop, one per shock.

Basic instructions by Koni come shipped with the shocks but for much better detail, click the links below to see exploded views of the full front and rear assemblies in full detail:
FRONT Exploded View <-- Click me!
REAR Exploded View <-- Click me!
Assembly tip: Start by spinning the collars all the way down as low as possible on the shock, then assemble everything shown in the diagrams above. With everything assembled and the top nuts tight, then raise the collars to the recommended starting height as the final step, putting tension on the spring. This way you are not fighting against the spring pressure when installing the top hat.
Damping adjustment tip: As with all Konis, the adjustment on the top of the shock to change from soft to firm is opposite from most other shock makers. With Konis, CLOCKWISE = Softer, and COUNTER-CLOCKWISE = Stiffer.

Setup for track weekend at Sonoma we added our Progress Sways and 17x8.5 RPF1 and 225/40-17 Continental Extreme Force Tires. Note we picked this tire because we want to use all the extra travel of this coilover setup. If you want to run 17x9 and 245/40 or our famous 17x10 and 255/40 then you want a different coilover with less total travel.

TRACK REPORT!

First time on track with our new coilovers, three days at Sonoma Raceway, and they proved amazing! Still a pretty 'soft' setup for serious track fun but advantages of the longest travel NC coilovers that exist included that we could cut all curbs and the car didn't care, it stayed on line and would not get knocked off line by even the most rough rumble strips. By the end of Saturday we had the car under 2 minute lap times with passengers. We started half a turn off full stiff at front and one full turn off stiff at rear and adjusted front to full stiff and rear to half a turn off full stiff for the control we wanted. We did find that we needed a quarter inch packer at the front corners clipped in to limit travel just a bit to prevent rub way up inside on front fender liners with relatively conservative 225/40 track tires. That's the cost of so much travel, this is not the setup for 17x9 and 255/40 unless you plan to add a lot more packers and give up a lot of the lovely travel of this setup. And that extra long travel is why this setup rides as good as it does for 7kg front and 4kg rear spring rates. We double stinted the car with multiple drivers and we all agreed it impressively quick for such a relatively soft 7kg/4kg spring combo. Around town we drove this setup on stock sways for best possible ride quality, but for the track weekend with high grip tires we added our Progress Sway Bars.

AUTOCROSS REPORT!

Our first autocross with this setup below and we got the win! BMW Club Autocross on rough busted up lot with koni set FULL STIFF front, one full turn off stiff for the rear. First place in Instructor "Gold" Class, fastest thing that uses gas on this day in field of 50 cars. Fastest run with passengers (which this club allows), a 10 percent weight penalty and we still got the win! Nonetheless, if autocross is your priority this is not my first choice in this price range, our MeisterR ClubRace and FEAL coilovers with much more spring rate and less travel will be faster through autocross slaloms. All the extra travel adds time to slalom transitions. All the extra travel of this setup also means you are limited on tire size that can be used, we did 235/40 here on our Enkei 17x9 RPF1 with quarter inch packers added all around to cut a bit of the travel. Even bigger 245/40 and 255/40 tires would take a lot more packers to further limit travel.