With 125 wheel hp, the 2,100-pound coupe flies down the quarter-mile in 14.5 seconds. "I've run a Roots-type supercharger at 8 psi, but this is faster." Pretty impressive for a motor running on atmospheric pressure alone. But drag racing isn't the main focus for this Mazda. Instead, Hoekstra uses a 45mm air horn and a 38mm velocity stack on his throttle bodies, achieving a nice balance of low- and top-end power for his favorite automotive pastime-autocrossing.
Hoekstra enjoys participating in the Street Mod 2 autocross series put on by the SCCA. The Miata is a perfect choice for autocrossing-light, plenty of power potential, and superbly balanced. But getting a leg up on the competition means stock is for suckers. Following this school of thought, Hoekstra called Koni for their struts, around which are wrapped Mazdaspeed springs. The fronts rate in at 600 lb/in, while the light rear end uses springs that are a mere 350 lb/in. A Racing Beat anti-roll bar stiffens the front end to keep the contact patches square for crisper turn-in. Polyurethane bushings are also used to complement the rest of the suspension.
Stopping this speedster are the stock 10.3-inch front and 10.1-inch rear rotors. The only modification to the braking system is the addition of Hawk pads at all four corners.
From the Mazdaspeed clutch and 8.8-pound Toda flywheel, power is transferred through the stock 5-speed and into a 1999 Miata rear differential. This is used for off-the-line grunt, which is upped with 4.30 gearing as opposed to the 4.10 gearing of the 1995 rear-end. Weight is important in any race car, especially this one, so twist is put to action through 15x7-inch Enkei RPF1 wheels, each weighing a mere 9.3 pounds. Stick is provided by Kumho Ecsta V710 autocross tires sized 225/50R15.
Outside, things are as original as the day it rolled out of the factory. No need to call attention to yourself-the sound of four individual throttle bodies does enough catcalling as it is. Inside it's much of the same-function over form. Hoekstra sits tight in a Cobra seat as he slithers around the autocross course, all the while holding onto a MOMO Race steering wheel. In addition to a lack of air conditioning and power steering, Hoekstra didn't waste his time with any audio equipment. He puts it best; "There's no need for audio when the engine sounds so awesome!"
What does the future hold for the Mazda? Hoekstra is staying focused on the SCCA Street Mod 2 autocross series. "I need some more power, so I'm going to run the 1999 motor." In these later models, the intake ports were raised from 39 degrees to 51 degrees, and incorporate solid lifters. The better flow, in conjunction with the planned JE 0.040-inch overbore pistons and a 12:1 compression ratio, will make the BP-4W motor a serious threat to the forced-induction engines and V-8's Jimmy will be running against in his weekend cone dancing. He expects to redline at 9000 rpm. The sound of the individual throttle bodies and a motor at nine grand should make everyone stand up and take notice. As should his spot at the top of the podium. Who says boost is better?
Fuji Racing Miata
EngineEngine Code: BP-4WType: 1839cc Inline four, aluminum block and headExternal Mods: Fuji Racing IRTB kit (throttle bodies, 45mm air horns, intake manifold, throttle position sensor, vacuum canister, throttle linkage), adjustable fuel pressure regulator, fuel rails, 38mm velocity stack, inlet air sensor, cat-back exhaust, 4-2-1 headerEngine Management Mods: Freedom plug and play ECU
DrivetrainLayout: Front engine, rear-wheel driveDrivetrain Mods: 1999 Miata rear differential, Mazdaspeed clutch, Toda flywheel
SuspensionFront: Koni shocks, Mazdaspeed 600 lb/in springs, Racing Beat anti-roll bar, polyurethane bushingsRear: Koni shocks, Mazdaspeed 350 lb/in springs, Racing Beat anti-roll bar, polyurethane bushings, polyurethane differential bushing
BrakesFront: Hawk padsRear: Hawk pads
ExteriorWheels: 15x7-in. Enkei RPF1Tires: 225/50R15 Kumho V710 Autocross
InteriorCobra seat, MOMO Race steering wheel
Hoekstra uses a 45mm air horn and a 38mm velocity stack on his throttle bodies, achieving a nice balance of low- and top-end power for his favorite automotive pastime-autocrossing.