open out

verb3

1. •
   To expand, to widen, to unwrap, unfold or uncover, to spread out from a compact state.

   • Once though the station the deep-throated exhaust of G.C.R. engines, and particularly the "Directors", could be heard in ascending crescendo as the drivers opened out to take the gradient. — 1954
2. •
   To facilitate wider access or expand options.

   • The plan will open out the region for trade.
3. •
   To increase the amount of air in an engine, such as by pressing on the accelerator to open a throttle plate or butterfly valve.