I own a MG ZS180 race car and it’s stil running the VIS manifold it has a motec ecu system Piper cams full exhaust. I have noticed whoever set it up when it was installed and dyoned just had the butterflies on the VIS open as soon as you start the car. I managed too get hold of a second hand manifold with the thinking of gutting the butterflies but when I opened it up and look inside and noticed these butterflies are actually not inline with the air ram tubes but come off into a mini chamber with no extra feed so would it be better too completely block them of and have air flow straight into the head from the TB and top air box after considering I never want too be dropping below 4K revs on a racetrack except at the start line anyways. Would much prefer too ditch the rubbish system for some itbs but its not too cheap. Just wondering has anyone blocked off the butterflies completely yet?