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How to Build a Locost in 48 hours Jan 8, 2004

This is the $1600 Miata we started with. Except for a missing window, ratty top, and general aura of moldiness, the car seemed to be in pretty good mechanical condition, which is what we were most concerned with. Had we been brave enough, it certainly would have made the 700 mile drive from Florida Once we pulled it into the shop at CMC, the teardown began. In a little over two hours, we went from a running, driving Miata, to a stripped shell and a pile of parts. Most of the car came apart with little trouble, although disassembling the dash was probably as complex an operation as everything e Though our Miata appeared to be in reasonable mechanical shape, it did seem to lack power, although the engine had decent compression. When we saw this section of the exhaust, we suspected that this may have had something to do with it. The CMC 7 frame awaits the guts of the Miata.

Admittedly, when we showed up at Champion Motorcars in Madison, Alabama, armed only with a ratty Miata, and faced the welded-up bundle of tubes we intended to turn into something resembling a Lotus 7, we were more than a little intimidated.

Stripping the Miata to a shell in a little over two hours eased our fears a bit, and when the real wrenching began, the light at the end of the tunnel began to glow brightly. In just over 48 hours from when we rolled the Miata into the shop, we drove out in a reasonably complete CMC 7, that could be autocrossed competitively this weekend with just a couple of hours of sorting.

Of course, the project wasn't simply to build a car quickly, but the quick assembly did make the point of how well thought out the CMC Miata-Locost package is. A reasonably competent mechanic could complete this project on his or her own in a month or so of evenings and weekends. You don't really even need many specialized tools--in fact, you'd probably be shocked to learn how much of the assembly was completed with adjustable wrenches.

With only a few exceptions, this is mostly a bolt-together project, with very little welding required. What welding is required does not require an expert, or even gorgeous welds (so long as they're strong).

One tip: Having the frame at waist level on sawhorses greatly aided the assembly and saved our backs a lot of pain. If you have the means to raise the car this high, take advantage of it.

Right next door to the CMC fabrication shop (okay, actually two doors down--right next door is a guy who build robots. No, not the cool kind that fight, the kind that build stuff) is the fiberglass shop where our body panels were being prepared. CMC did a pretty good job at matching the Smurf Blue of our donor car, which we thought was a nice touch. The body panels were a nice fit, too, with no trimming of fiberglass required once they were installed.

What we brought home was pretty much a complete car. It needs its street equipment (lights, etc.) put in place and wired, a good nut-and-bolt once over, and some miscellaneous hardware installed, but apart from that, it's a real car.

We've had it in our possession for about a week now, and it's just starting to sink in. Actually, every time we walk into the garage we can still smell the fresh fiberglass curing, so our euphoria might be chemically induced.

Anyway, in our time with it, we've mostly been taking inventory, cleaning it up and getting it ready for the finishing touches, which mostly include the installation of the equipment to make it street legal. Front head and marker lights are mounted, and we have some cool-looking Caterham-style rear lights to complete the package.

We're also exploring seating options. While the Miata seats fit nicely, and look appropriate, they are more suited to taller drivers because of their location. They use the rear firewall of the car for support, so there is little adjustability available save for extra padding. At any rate, we're probably going to need more support for autocrossing than the stock seats will provide anyway, so we've been talking to Ultrashield about using one of their Spec Miata seats. These seats are designed for narrow environments, so they should work in our CMC. Now all we have to do is devise some simple, safe, adjustable mounting system. Suggestions and E-mailed diagrams are welcomed.

This weekend we plan on tackling most of the wiring duty for the lights. 

Locost shakedown Feb 12, 2004

We recently took out Locost out to Ocala Grand Prix for some shakedown laps, and basically to see if anything was going to fall off. After a thorough nut-and-bolt check, we hit the track and learned that even though our Locost has not been aligned with anything more accurate than the human eyeball, it's a hoot to drive. At least until the front wheel starts to come off. A bent wheel that was not allowing the lug nuts to stay tight was the first problem we encountered, which is easily fixable with some cooler wheels.

The other problem we encountered will need a little more extensive solution. After a few laps, a horrible clunking noise began to be heard from the rear of the car under acceleration. What we originally thought was a diff failure turned out to be more of a design oversight. The Miata diff is usually connected to the engine and trans through an aluminum powertrain brace. With the shortened driveshaft and narrow center tunnel of the Locost, there is no way to install such a brace, and the Miata rear end simply hangs in the back of the Locost on two rather stout bolts. This works fine until you apply some torque and the diff tries to twist out of the frame (that's bad).

A solution needed to be devised to better locate the rear end, so we visited out local Miata expert, Stu Brumer of BSI racing. After complimenting the overall design and sturdiness of the Locost chassis, he helped us brainstorm some ways to control the torque at the rear end. Our solution was to affix ears to the back of a stock Miata housing, then run a brace rearward to a new mount that will be affixed to the chassis. Using rod ends will allow us to preload and adjust the differential angle. BSI is currently in the experimental stages of their solution. We'll shoot some pictures when fabrication begins. Hopefully by this time next week the brace will be in place and the Locost will be ready for some zero-60 sprints. 

Top 5 Questions Aug 5, 2004

**Can I do this?
Well, probably, if you're a decently-abled mechanic and have a reasonable knowledge of the basic workings of an automobile. Actually, the best thing to have during this process is a good sense of organization. You'll be dealing with a bunch of little bits and pieces that were designed to go in one car that are now about to go on a completely different car. A digital camera would be an excellent tool to add to your box, as would the usual assortment of plastic bins and bags and Sharpie markers. A written or even video journal could help you put back together things you once took apart, as well.

Aside from those warnings, yes, you probably can do this. Maybe the most important thing to have when starting a project like this is the determination to finish it. If you have that, you're probably in good shape.

What's up with the rear end?
A lot has been said about the rear end in the Miata-Locost, or, rather, the shortcomings of the rear end. Here's the deal: In the initial Miata-Locost frames, there was no real provision for proper rear end locating hardware. In our car, this led to the failure of the pinion gear and a floppy rear end, which is great for a bachelor party, but less so for a sports car. Subsequent versions produced by CMC have the provision for more positively locating the rear end and supposedly work much better.

A properly located rear end is important not only to the reliability, but to the performance of thse cars. The Miata is equipped with a substantial powerplant frame that locates the rear end for just this reason. As the Locost is considerably shorter and narrower, use of the stock frame is not possible (though one builder supposedly modified his Locost frame to accept a modified Mazda PPF), but a suitable locator must be used just the same.

In our case, we had BSI Racing fabricate a pair of heim-jointed rods that attach to a cross piece welded to the diff housing and transfer the load forward to the bottom of the frame. Their beefy enough to take a lot more power than we are giving it currently, but it's good to have durability in reserve.

What kind of wheels and tires fit?
Stock Miata wheels and tires should work fine. A 14 x 5.5 or 6 wheel with a 185 or 195/60-14 should fit under the stock fenders fine. We found a set of Miata wheels with some 205/55-14s mounted on them and had a little trouble getting them to clear the rear fender lips. Five minutes with a power sander fixed that, though. If you'd like to go to 15-inch wheels, you'll have a little more trouble. The fronts are fine, as the fenders move with the wheels, but the rears are very tight. We've heard of owners spacing the fenders out from the body, or grinding copious amounts off of the fender lips to get the tires under the car.

Is it street legal?
Depending on what state you live in, you should be able to make a Locost street legal. In Florida, all we need are a windscreen, some lights, and seatbelts. Other states are tougher, but your local DMV should be able to give you a list of what you'll need to be legal. You'll also get an MSO (manufacturer's statement of origin) with the kit, so that will serve as the document you'll need to get your title.

*So it's street legal, is it fun on the street?
If looking up at the undercarriage of Honda Accords is fun, then yes, it's fun. As a daily driver, call us spoiled, but we demand a little more creature comforts and safety than a car that's about the size of a large motorcycle can provide for daily use. As a once-in-a-while blast to the beach or the cruise-in kind of thing, though, it's perfectly fine. Don't forget, even though it has fenders, you'll still get pelted with a lot of crap from the front wheels. Always wear proper eye protection in one of these things.