Video: Supercharged Miata Slithers In Pursuit of ITB-Spec Miata

If the best qualities of Mazda’s sports cars are their handling brilliance and their ability to do plenty without much power, a tight and twisty course would be the best place to put that assertion to the test. Lime Rock’s autocross track, which is half-mile permanent, paved facility (not cones in a parking lot like many autocross courses), is the perfect place for these two Miatas. Thanks to the track’s nuances and two bold drivers, they demonstrate just how much fun a low-powered, lightweight car can be if the balance is right, and the car is playful and communicative on the limit.

An Emphasis on Response

The white NB Miata is no powerhouse by any stretch, but it is effective on this hairpin-dotted course. Its 185 horsepower and 134 lb-ft of torque aren’t enough to write home about, even in a 2,230-pounds car, but this powerplant compensates with exhilarating response. It uses a block from an ’02 Miata with 10:1 compression, a Supertec titanium valvetrain, Maruha 264° cams, Toda camgears, TWM individual throttle bodies, a Maruha VP race header, and an Adaptronics ECU. With a Mazdaspeed six-speed, a lightweight Fidanza flywheel, and a 4.10 Torsen differential, it makes good use of what power it has.

The NB’s footwork benefits from Energy Suspension polyurethane bushings, Tein Flex coilovers, Racing Beat swaybars, and lightweight Enkei RPF1 wheels wrapped in 205/45/16 Dunlop Direzza DZ102 Tires. These make the car sharp and progressive, and that shows in the way its driver, Quinn, can exploit it. Its speed into corners is remarkable.

When the NB breaks away, and it does so often, it slides in a more controllable fashion.

No Arguing With Grunt

The 1.8-liter supercharged NA Miata, which we’ve seen here before (a technical clarification: “NA” refers to the chassis code, it’s not an acronym standing for normally-aspirated), has the ability to reel in the ITB-equipped car easily. With 245 horsepower and 185 lb-ft of torque at the wheels, put to the pavement via BF Goodrich Rival S tires and Flyin’ Miata’s V-Maxx coilovers, it’s in another league in terms of straightline speed. However, extra punch is only as useful as it is usable on a tight course like this.

Precision Pays Off

When the NA takes the lead (7:09), the differences between these two become most noticeable. The supercharged NA can’t quite put the power down as well as the NB. However, once the road straightens, the NA ekes out a three-car gap, even though Quinn can put his normally-aspirated power down more accurately (9:46) and with less wheelspin. This is a huge advantage in tight hairpins, and is also what keeps the supercharged car from sprinting off towards the horizon.

The way the supercharged car gives up grip causes its driver to take his hands off the wheel after running out of lock (5:58). This car isn’t as easy to exploit at the limit of adhesion.

The blue car isn’t as predictable, progressive, or easy to lean on, and that shows through the repeated locking of the brakes. This over-driving allows Quinn in his NB to close the gap spread over the short straights, almost every time. There’s no question which car is more accurate around this demanding mini-course.

The differences are most obvious during the “Sudden Death” session, when the NB’s rear tires are fully up to temperature. It’s able to change direction much better, which allows Quinn to take tighter lines. This accuracy pays dividends. So does its predictability; Quinn can clearly lean on his white NB a little harder without over-driving. With such closely matched cars, the NB holds a marked advantage with its behavior at the limit.

It’s a close battle between these two scalpels; chock-full of spectacular saves and lots of oversteer. Although they declare it a draw, we all know which car would sail away over a longer race. Time to start browsing CraigsList for a nice NB.

 

 

 

About the author

Tommy Parry

Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, he worked jobs revolving around cars throughout high school, and tried his hand on the race track on his 20th birthday. After winning his first outdoor kart race, Tommy began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a track day instructor and automotive writer since 2012, and continues to race karts, formula cars, sedans, and rally cars in the San Francisco region.
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