aFe Silver Bullet Throttle Body Spacers TBS Jeep Wrangler (TJ YJ) 91-06 4.0L 1977-chevrolet-k10-suburban-scottsdale-esi4916634 5/16" U-Bolt w/standard nut

5/16" U-Bolt w/standard nut

The exhaust sound provides accoustic feedback of engine rpm to aid the driver in critical decisions such as gear selection or throttle input in rev-match shifting

but the bumper is otherwise bolt-on

The X1 Series provides flexible performance that grows as your fuel system grows

aFe Silver Bullet Throttle Body Spacers TBS Jeep Wrangler (TJ YJ) 91-06 4.0L 1977-chevrolet-k10-suburban-scottsdale-esi4916634 5/16" U-Bolt w/standard nutSilver Bullet throttle body spacers create turbulence in the air flow at the point just prior entry into the engine increasing horsepower, torque and improving throttle response and fuel efficiency. Silver Bullet throttle body spacers are constructed out of durable T 6061 billet aluminum and using a unique serrated helix entry to create turbulence at the manifold while eliminating the annoying whistle found in other helix only throttle spacers.