The aFe Silver Bullet throttle body spacer (46-31004) is a bolt-on aluminum spacer that sits between the intake manifold and the throttle body on the E36 M3's inline-six. The manufacturer describes a serrated/helix design (US PAT 07055513) that creates turbulence in the intake manifold and increases air pressure in the combustion chamber. The body is precision machined from 6061-T6 billet aluminum, and its inset shape is meant to suit the E36's compact engine compartment.
Gains over stock are modest, so buy this for throttle response and noise, not big power. The manufacturer reports +4 HP and +8 lb-ft in dyno testing on an S52 E36 M3. Its serrated entry is also designed to reduce whistle sound, which helix-only spacers often produce. Owners on user forums are skeptical that spacers do much on fuel-injected engines, so set expectations accordingly. The product title lists it as 50-state legal, which matters if you live in a CARB state.
The manufacturer lists the BMW M3 (E36) L6 3.0L and 3.2L engines (S50/S52). Year ranges differ between sources, with 92–99 in the product title and 94–99 on the manufacturer's page, so the manufacturer should confirm the exact years for your VIN before you order.
The manufacturer says the serrated/helix entry reduces the whistle that helix-only designs produce. Owners on user forums report that spacer results vary, so treat noise reduction as the manufacturer's claim rather than a guarantee.
This is a bolt-on job that requires removing the intake elbow and the four throttle body bolts, then fitting the spacer and gasket between the manifold and throttle body and reinstalling the throttle body with the longer bolts supplied. An owner on a user forum described the process as pretty straight forward. The manufacturer's install sheets for other Silver Bullet part numbers call for a basic metric socket set, a 10 mm socket and wrench, and a 14 mm socket and wrench, and they stress that the spacer is designed to fit with the stock intake system, so aftermarket intakes may need modification. Those sheets also warn DO NOT OVER TIGHTEN as it will crack the plastic throttle body, so confirm the torque for this part number before you start.
