DIAL IN YOUR BOOST! Adding shims beneath your impeller may bring you some boost you are missing. It only takes minutes to check how much room you have for impeller shims, and to add them if needed.
Our shims are made from stainless steel, and are an exact fit to all Powerdyne and O2 Force impeller shafts and many others.
Kit comes with two .01" shims and two .02" shims, and easy-to-follow instructions.