If for no other reason, our shared desire for "the next best thing" is what gives the sport compact culture a more progressive and dynamic quality than any other in the world of automotive customization. Fueled by rapid technological advancements among OEMs, and complemented by a proportionately growing aftermarket, today's tuners are able to develop more efficient methods of realizing their goals than ever before. Accomplishments that were cutting edge only a few years ago are all but commonplace, thanks to the readiness of tuners to embrace new technologies. Sport FWD drag racers need to run consistent 9-second passes to stay competitive, while all-motor, in-line four's routinely reach the traps in less time than their turbocharged brethren three times as powerful. AWD consumer sedans regularly break circuit track records long held by purpose-built RWD roadsters, some even besting open-wheel, multimillion-dollar race machines (think AMS). And if your daily driven street car isn't producing three times the power, or accelerating to highway speed in half the time it was originally intended to-forget gaining any respect on the streets. Still, however surefooted our advancements seem to be, every step forward is built on countless steps back, as it seems the very same enthusiasm that allows tuners to master their goals prompts some to make hasty mistakes that bring hard-shaken misconceptions for all to overcome.
In the performance end of the sport compact world, almost every new technology (or adaptation of an old technology) is met with a lingering air of fear and uncertainty, no matter how beneficial it may eventually prove to be. A decade ago, tuners were reluctant to turbocharge their rides, fearing the same disastrous outcomes met by a few DIY-ers who were eager to increase power without first properly learning how to. Likewise some stubborn Honda B-series tuners who unsuccessfully rushed into K-series projects wrote the engine off as garbage, initially giving it a bad reputation. While the efforts of others eventually shed light into the darkness, disproving once golden rules of: "Turbocharging will blow up your engine," and "K20s are weak," tuners could have realized an even more rapid evolution of their sport had initial efforts been better planned beforehand.
Individual throttle bodies (ITBs) seem to be one such technological adaptation that remains a fearful mystery to many SpoCom enthusiasts. Despite a rich history of success among potent racing teams and consumer OEMs alike, sport compact tuners are slow to embrace ITBs, influenced in big part by well-circulated misconceptions and negative experiences a few have had with them. In reality, with proper tuning, ITBs have proven beneficial in almost every arena applicable to sport compact performance, yet rumors that they aren't streetable, are only useful for top-end power, won't pass emissions testing and destroy fuel mileage are repeated in conversation add nauseam-to the point that many tuners wouldn't give them another thought.
Nissan's Skyline GT-R and Pulsar GTI-R, BMW's M coupes, Toyota's 20-valve 4AG engine and McLaren's F1, not to mention modern fuel injected sportbikes and almost every winning F1 car in the past quarter century, all have one thing in common-none uses a single-throttle, intake manifold found in most consumer cars; they all breathe through ITBs. Whether used in a turbocharged or naturally aspirated application, with four, six, eight or more cylinders, ITBs simply work. In the average piston engine, each cylinder gets its own of every necessary component-spark plug, fuel injector, intake and exhaust port(s) and intake and exhaust manifold runner-except a throttle body. It doesn't make much sense, until you consider the inclusion of a single-throttle manifold from an OEM perspective: "Individual throttles are a very expensive feature," explains Lance Hayward, of British Columbia-based ITB manufacturer Hayward Performance. "Single-throttle, plenum manifolds get the job done on most consumer applications, but can never optimize (an induction) system's full potential, especially for naturally-aspirated cars."
As Lance explains, air is most efficiently introduced to an engine through a straight, unobstructed path into the cylinders, along a "port-centerline"-something a single-throttle, plenum manifold can't offer. "ITBs allow each cylinder to aspirate equally, and in the most efficient way possible," he explains. "In a conventional plenum manifold, some cylinders are farther from the throttle than others, thus air has to travel different distances and along different paths to reach the cylinders." Aftermarket exhaust manifold companies always tout the benefits of "equal length runners" in the exhaust, so why not in the intake too?