have a astra with a 1.6vvt z16xer engine and would like to understand how the vacuum controlled flaps within the sealed inlet manifold work, the flap. very much like a throttle flap I think? is operated via a vacuum solenoid electrically controlled from the ecu is it similar to twinport ?

  • All it does is change the intake runners from long to short, Which changes the torque and horsepower of the motor during low rpm and high rpm.
    – Moab
    Apr 20 '18 at 20:44

As engine speed increases, the flaps are gradually opened until, at around 2,000 rpm, they are parallel to the airflow and present virtually no resistance. Their purpose is to ensure that the air entering the cylinder is sufficiently turbulent for good fuel-air mixing even at low engine speeds. This aids in reducing certain toxic emissions and may also improve low-end power and torque.

Link https://www.avontuning.co.uk/services/swirl-flap-removal

Not the answer you're looking for? Browse other questions tagged or ask your own question.