Some of you may recall that four years ago I sold my K04'd B5 S4 to go spec miata racing. It's a hoot and I've got no regrets: I can't imagine having more fun at the track than being in the middle of an SM race. But for non-competitive track days an SM is, to be blunt, a weakling. Fast in the corners, but with nothing to give on the straights. How about all that light and nimble spec miata goodness (and low costs!) with twice the power? Thus was born my Mazdaspeed Miata track car project, which is now 'complete'. (Is any track car project ever really finished?).



The Mazdaspeed Miata was the swansong of the 2nd gen miata line, notably more powerful than its predecessors due to the inclusion of a small turbo from the factory. Factory power spec was 178hp (crank) with 7.25 lbs of boost, but the car is well known to be heavily air restricted.

The starting point was this insurance auction special with only 2295 miles on the odometer, $10,500 including delivery and broker fee. There was no frame damage.



Said to be a dealer car that had a rough test drive, it came with the window sticker listing a $27,125 Total MSRP. The front had been smashed in, and there was a clean cut/tear though the convertible top, which frankly looked a lot like someone put a knife through it, perhaps a little insurance fraud to make sure the car was written up as totaled (the soft top is a $3000 part). For my purposes the damage was largely inconsequential - radiator and intercooler upgrades were part of there build plan as was bolting on a hard top.

The car was completely stripped and a custom cage installed, with Nascar bars on both sides.



By SM standards the cage is 'illegal', as it has extra mounting points on the firewall and A pillars. Driver and passenger each get a kirkey seat, 6 point harnesses, and window net hardware. We also installed a quick-release steering wheel.



Power upgrade comes solely from better breathing, with a new intake and larger intercooler (each from Flyin Miata). Boost is regulated to ~12lbs peak.



Some custom piping was used to simplify the air pipe routing, as we had removed the AC unit and thus didn't need to route around it. An open exhaust was also fabricated and installed. We also put in a competition radiator, since these cars were known to have cooling issues. Brakes are stock. Our starting point on suspension was the Mazdaspeed spec miata kit, with dampers revalved (as per an apparently common SM cheater spec). For wheels and tires, I'm just using old competition tires from my SM (Toyo RA1, 205 50 15). The current dry weight of the car is ~2100 lbs.

While this was supposed to be plug and play, of course it was not. Initial testing had the car overheating after just a couple of hot laps, and the car was repeatedly overboosting and then cutting out. Plus it had heavy understeer. The overboosting was eventually traced to a faulty wastegate diaphram. Understeer was dailed out by changing spring rates and swaybar settings.



The intercooler hogs most of the airflow. To solve the cooling issues we fabbed ductwork so air cannot bypass the radiator, and added some extra openings in the bumper cover to allow more air in, above the intercooler and directly in front of the radiator.


On the track
This Saturday at NHIS I ran the car in this `final' form for the first time. Wow! It's very fast and involving, and clearly retains the light nimble neutral chuckableness of an SM, but with great power (~200 rwhp on a dyno dynamics dyno @ ~12 lbs of boost). The extra power means much more active throttle steer than an SM, and later corner entries to account for the much more aggressive powering out of turns. The close spaced stock 6-speed means near constant gear changing. The shift pattern for NHIS chicane-chicane, starting with the run out of the final corner, is 3-4-5-6-4-3-4-5-3-4-5-3-4-5-4-3. My 1.6l SM (5-speed), in contrast, is 3-4-5-4-3-4-2-3. It's incredibly involving to drive with the extra power and shifting, and takes much more energy than piloting an SM at a track day. I left the track really tired! Running on SM spec wheels and tires (as per my plan), it's under-tired, but I'll probably just live with that.

There was no lap timer in the car, but it's clearly got several seconds on a SM and it easily outpaced the Elises on track (this was the instructor group, so one would hope they were well driven). I think it can hang with or out run just about anything at NHIS, although at a place like the Glen it won't have the top speed of a big power car.

Towards the end of the session the brakes were going soft. We'll try ducting through the fog-lamp openings for starters, but bigger brakes may be required (which might mean bigger wheels, too). Or I could just brake less!



Total cost? Under 30K, including labor. All work was done at DWW Motorsports.

Car long since sold. Sig is for historical purposes only.