1990 Mazda Miata - The Mini Monster

For typical automotive literati, the term "Miata" doesn't conjure sinful images of tire-annihilating burnouts, pegged boost gauge needles and Hennessey Viper-shaming performance. In fact, most normal folk associate Mazda's diminutive roadster with gray-haired AARP members, golf and weekend cruises down the coastline. Those people should put this magazine down right now. When it comes to the "400 Horsepower Club," normal people need not apply. In fact, those people could injure themselves simply trying to comprehend just how unusual Ric Stephen's Miata really is.

While 400-plus hp Eclipses, Integras and Sentras are impressive, let's not forget that most of that remarkable potency is lost in the form of white, carcinogenic smoke billowing from overwhelmed front tires. It doesn't take a genius to conclude that such behavior isn't an efficient use of the given resources. Now imagine if we were to strip a few hundred pounds of extraneous mass from those tire-spinning sport compacts, while endowing them with enough traction to make a Hemi Cuda rust with envy. You will then end up with what Stephens refers to as the "miniMONSTER," a vehicle that has not only shattered every preconceived notion of what a Miata is capable of, but also illustrated that such feats can be accomplished with just a few carefully chosen bolt-on components.

Bolt-on? You heard right. The miniMONSTER is living proof that it doesn't take deep pockets to earn entrance into this elite club. Stephens' plan of action was reasonably straightforward.

First, he found a clean, 1990 Mazda Miata for not much more than the cost of a big screen TV. Then, he swapped the venerable 116 bhp 1.6-liter engine with a slightly more modern, but equally inexpensive, 128 bhp 1.8-liter Miata engine. Next, he match-ported the cylinder head to take better advantage of the high boost pressures he knew he was destined to run.

Since the 1.8-liter engine was to remain internally stock, Stephens had to focus his efforts on proper engine management. To ensure accurate spark timing, which is critical to engine longevity and a reasonable safety margin, he chose to go with an Electromotive TEC-II programmable engine computer. Equipped with both a high-resolution crank-mounted trigger wheel for spark timing accuracy and a set of high-output ignition coils. Also driven by the TEC-II are four low-impedance 550cc/min RC Engineering fuel injectors. To ensure proper cylinder-to-cylinder fuel distribution and sufficient flow reserves, Stephens installed a high-flow fuel rail from Vishnu Performance Systems and a Peirburg in-line fuel pump.

Of course, Stephens didn't forget about the turbocharger. While the sound of rolling ball bearings and fanciful ceramics appeal to any techno-saavy gearhead, it is size that ultimately counts when it comes to heavy breathing turbochargers.

Reasoning that a turbocharger can be as much of a power handicap as a power generator, Stephens opted for a venerable, but reliable, T3/T04 hybrid for the task at hand. Mounted on a custom cast log-style exhaust manifold from Bell Engineering, the big Garrett turbo barely fits within the confines of the engine bay. In fact, Stephens had to cut a notch out of the unibody to make way for the big turbine housing. With no air conditioning compressor and power steering pump to clutter the engine bay, Stephens had several options to route the intercooler plumbing. For the lowest possible pressure drop, the turbo compressor discharge tube makes a straight shot downward and then forward to the top end tank of the massive front-mount air-to-air intercooler. Once pushed through the core, the air charge departs from the bottom end tank and makes a direct shot outward and upward, right into the stock throttle body. While there is nothing too elegant about the set-up, there's enough function to stain the pants of even the most jaded horsepower-junkies.

"There's really no secret as to how the car makes so much power without blowing up," said Stephens. "It just required solid engine controls, a good fuel system, good engine lubricants (he uses Leading Edge 5W/30 motor oil) and countless hours of dyno testing. There's no doubt in my mind that the car can be even faster if given a generous budget. But for the time being, I am making do with what I have and am trying to get as much seat time as possible."

Apparently, the seat time is paying off. In the past year, the miniMONSTER has whittled down the competition in the NHRA/IDRC Street Tire class (yes, he runs on BFG DOT-approved drag radials wrapped around Enkei RSF2 aluminum wheels), running his best E.T. of 10.98 at 125.59 mph. Even more impressive are the outstanding 1.5-second 60-foot times that the car seems to whip off with remarkable consistency. Stephens admitted that he felt "those violent launches are only possible through the ACT Extreme pressure plate coupled with a six-puck ACT copper disc."

Looking at the dyno results, one cannot help but be impressed. Especially considering that the very same Miata engine is only capable of mustering 110 wheel hp in stock form. But what's with the big mid-range torque dip? Judging by the TEC-II engine monitor display, the 550cc/min injectors had reached 85 percent duty cycle at approximately 5000 rpm, at which time they failed wide open (as one would expect from any over-driven injector).

Due to the resultant over-fueling, torque output dropped substantially, only to gradually rise as the engine consumed more and more fuel. However, judging by the datalogs and dyno graph, which show peak horsepower at a low 6000 rpm, it's clear that those oversized injectors are still undersized for this high-output application.

By no coincidence, Stephens is already working on a staged injection system, using an additional four 550cc/min injectors-one mounted in each of the four intake runners. Fully equipped with the necessary fuel system components, there is little doubt that the miniMONSTER will return with even more wind beneath its wings. And when it does, we'll be there.