The ST also gets an overboost program, increasing turbo pressure to 21 psi, and delivers 197 hp and 214 lb-ft. The overboost is good for 20 seconds a crack, with no recharge time. Floor the gas pedal and you'll get all 21 psi for up to 20 seconds. Release the pedal, floor it again, and you're back to max boost.24 Mar 2013