aFe Silver Bullet Throttle Body Spacers TBS 01-16 Nissan Patrol (Y61) I6-4.8L w/ Automatic TransaFe Silver Bullet Throttle Body Spacers TBS 01 16 Nissan Patrol (Y61) I6 4. 8L w Automatic Trans Serrated Helix Design: The Serrated Helix design creates air turbulence in the intake manifold. This turbulence increases the 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. 6061 T6