aFe Silver Bullet Throttle Body Spacers TBS Nissan Patrol 10-16 V8-5.6LThe Serrated Helix design creates air turbulence in the intake manifold to increase air pressure in the combustion chamber resulting in increased horsepower, torque and improved throttle response. The Serrated Helix combination design also reduces intake whistle that occurs with other helix only designs. (US PAT 07055513). Made from 6061 T6 Billet Aluminum aFe Silver Bullet Throttle Body Spacers are precision machined for lightweight, high strength