Many people seem to be under the false impression that the new Valvetronic engines don't have a throttle body. This is clearly not the case however the throttle body for these applications functions as part of the traction control system, as well as a safety valve of sorts. Regardless of the function the size of the hole still represents a restriction of intake air-flow, making the larger bore of the Dinan high flow versions enable the engine to breathe better for more horsepower and torque, most effectively in wide-open throttle scenarios.