aFe Momentum GT Pro Dry S Cold Air Intake 51-76309 – BMW 340i / 440i / M240i (B58)

OVERVIEW

aFe Power's Momentum GT cold air intake for the B58 replaces the factory airbox with a sealed, high-flow system rated at 400 CFM at 7" H2O. aFe measured maximum gains of +13 horsepower and +13 lbs. x ft. of torque, with the system outflowing the stock intake by up to 13%.

The smooth one-piece roto-molded housing is sealed and fitted with an auxiliary air scoop, eliminating the multi-piece construction of a factory box and drawing the coolest available charge. A large clear sight window built into the housing allows filter inspection without disassembly, and the patent-pending filter-to-housing interface maximizes usable filter area while keeping the part count low.

This version uses the oil-free Pro DRY S element: a large 8-3/4" oval, 360-degree radial-flow filter with three layers of progressively finer porosity synthetic media. It needs no oiling and washes clean with soap and water. A CAD-designed, dyno-tuned roto-molded intake tube connects to the turbo, a custom high-temperature reinforced silicone elbow coupling adapts to the factory breather line, and premium stainless-steel clamps secure the assembly. No cutting or drilling of factory parts is needed.

SPECS

• 400 CFM rating @ 7" H2O
• Maximum gains: +13 HP and +13 lbs. x ft. torque
• Outflows the factory intake by up to 13%
• Filter: Pro DRY S, 8-3/4" oval, 360-degree radial flow, oil-free
• Filter media: three layers of progressively finer porosity synthetic media, washable and reusable
• Housing: one-piece roto-molded sealed housing with auxiliary air scoop
• Built-in sight window for filter inspection without disassembly
• Patent-pending filter-to-housing interface
• Intake tube: CAD-designed, dyno-tuned, roto-molded
• Custom high-temperature reinforced silicone elbow coupling for the factory breather line
• Premium stainless-steel clamps
• No cutting or drilling of factory parts
• Not CARB exempt

PARTS INCLUDED

• Pro DRY S air filter (21-91103) — 1
• Intake housing (05-76309B2) — 1
• Intake tube (05-76309B4) — 1
• Screw, Torx M4 (03-50490) — 2
• Clamp, #060 (03-50002) — 2
• Silicone double-hump coupling (05-01417) — 1
• Rubber mount (03-50534) — 1

TECH RESOURCES

Additional Parts Required

• None. aFe Power specifies no additional hardware for this intake — it is a complete bolt-on kit.
• Installer supplies basic hand tools: metric sockets and wrenches, Torx drivers and a trim tool for the engine cover clips.
• Optional service item: aFe Pro DRY S filter cleaning kit (water-based, no oil) for periodic filter maintenance.

Installation

• aFe Power 51-76309 / 54-76309 Momentum GT cold air intake — installation instructions (PDF)

Notes

• Note: This intake system is not CARB exempt at this time and is not legal for sale in California or use on vehicles registered with the California Department of Motor Vehicles.
• aFe Power states this air intake system will not fit convertible models. Year ranges above follow aFe's official installation instructions, which run later than the 2016–2018 range shown in the product title. Confirm fitment with Speed Logic if your car is a borderline model year or a non-US market variant.

PART NUMBER

• 51-76309 — Momentum GT intake with Pro DRY S oil-free filter (this listing)
• 54-76309 — same kit supplied with the Pro 5R oiled filter

VEHICLE APPLICATIONS