FOX has been a suspension specialist for 40 years, and have won a huge range of motorsport events from the Paris-Dakar to the Indy 500. As a supplier to Ridetech, they've dominated Pro Touring recently. It's fair to say they know their way around shocks. They also understand the importance of proper suspension travel. Since they've also supplied shocks for the Ford Raptor, they also know how to build to an OE level of quality and durability. So, as you can imagine, we were pretty excited to work with them.
To develop these coilovers, we took measurements of the suspension's full range. FOX then designed a shock setup that would work throughout the whole range. After an initial fitting and test, they brought their race trailer out to our local track and we spent two full days with a two FOX engineers, three Miatas and two drivers to fine-tune the valving. We baselined against our current offerings, and used cars ranging from a typical FM II Miata to the 500 hp Targa Miata. This is the end result - a Miata suspension built from the ground up for us.
Our goal was for a high performance suspension that wouldn't punish on the street. We placed an emphasis on stability in corners, turn-in and body control combined with a very high level of grip. The adjustment was designed to primarily adjust the low speed rebound damping, which is mostly affected by body movements. You can adjust from a street setup to a hyper-aware track setup quickly and easily.
There are a lot of little details on these parts that aren't immediately obvious. The springs sit on a high density plastic ring that acts as a bearing, allowing the spring to rotate on the perch without the expense of a Torrington bearing. The internal washers are disc ground for high accuracy, giving more consistent behavior of the shock. Even the body of the shock is given Kashima coat, which is a superior form of hard anodizing to protect the shock under the worst conditions. The lower bearings have a Teflon liner so there's no need to grease them. Even the shocks are light - 40% lighter than a typical aftermarket unit. They are a monotube design.
The shocks have 5" of shaft travel. That's pretty spectacular, and it's part of the reason they can deliver searing track performance without punishing you day-to-day. When we put an experienced Miata driver and track instructor behind the wheel, he couldn't believe how comfortable they were on the street and how hard he could hit the berms. They just work.
Due to the long travel and maximum compression available, you can run just about any ride height with this setup. If you want to run low, the shocks will allow the suspension to compress as far as possible. If you want to run high, that long shaft travel will mean you still have droop available. You may have to use a longer spring for particularly high heights, such as a Baja application.
The standard spring set is 550 lb/in front and 375 lb/in rear. This is suitable for street use and track use, and it's what we use on the V8 cars we build for customers. On the V8 track car, we used 750/500, and the standard valving can deal with up to 900 lb front springs.
The springs will go loose at full droop. To avoid this, we do offer a helper spring kit for an extra $250. They won't make a difference to how the car drives, but they will keep the springs seated when the suspension is fully extended. It's mostly for ease of maintenance.
There may be some interference between the bottom of the shock and V8Roadster lower control arms. Some grinding will be required in this case. 2001-05 upper front control arms can also make contact with shock bodies depending on alignment, although this is less likely with the slim shock body of the Fox than some other setups. Please make sure there is no interference when you install your shocks.
The kit includes four shocks, bumpstops, front and rear springs (unless you choose "none") and some bushings. You will reuse your factory upper mounts and your existing lower bushing. If you'd like all new replacement parts, order the NA version. These shocks are built in the USA and can be rebuilt. 1-Year Limited Warranty for the original customer against defects in materials and/or workmanship. Custom revalving is available from Fox for $35/shock.