MACE MANIFOLD PLENUM SPACER KIT TO SUIT NISSAN ALTIMA L33 VQ35DE 3.5L V6Our plenum spacer sits between the plenum and plenum cover. Its main purpose is to improve air distribution between cylinders by slowing down the air speed inside the plenum chamber. As a result, there is less of a pressure drop inside the plenum chamber between cylinders and less air momentum. This, in turn, feeds each intake runner more evenly improving throttle response and bottom end torque. The change in airflow characteristics is shown in the