Q: Someone said my car would go better if I removed the ‘grommet’, what’s that? A: The ‘grommet’ is a restrictor that is part of the standard boost control system and features in virtually all Evo’s. Basically it is there to provide a smooth control of the boost level. If you remove it the boost level will indeed increase however you will lose the smooth transition. The increase in boost may also cause fuel cuts (see elsewhere). Although it may sound like a free boost upgrade, it is generally considered to be a bad idea to remove the ‘grommet’. Back to question page