2-5/8" Boost/Vac Gauge 30inhg-0-20 psi (w/ warning) - JDM Datsun Z Series R25-BV3-DATZ The Datsun Boost/Vac Gauge is a must-have instrument for precision monitoring of your vehicle's forced induction system. With a variety of ranges, it provides real-time readings of the engine's boost and vacuum levels, enabling you to optimize... $342.98