aFe Magnum FORCE Stage-2 Pro Dry S Cold Air Intake – BMW 135i / 335i (E8x / E9x, N55)

OVERVIEW

The aFe Power Magnum FORCE Stage-2 sealed intake system replaces the factory airbox on the N55-powered BMW 135i, 335i and X1 35ix. A CAD-designed, dyno-tuned roto-molded intake tube pairs with a large 5" conical filter to outflow the factory intake by 32%, worth up to +16 horsepower and +26 lbs. x ft. of torque on aFe’s dyno.

This version uses the oil-free Pro DRY S filter: three layers of progressively finer porosity synthetic media that clean up with a simple wash and air-dry, with no re-oiling step at service time.

All necessary hardware is supplied. The kit is a direct bolt-on that requires no cutting or drilling of OEM parts.

SPECS

• Dyno-tested gains: +16 HP and +26 lbs. x ft. of torque (peak)
• Outflows the factory intake by 32%
• Filter media: aFe Pro DRY S oil-free, 3-layer progressively finer porosity synthetic media (aFe P/N 21-90083)
• Filter size: 5" tall conical, 360-degree radial-flow element
• Intake tube: CAD-designed, dyno-tuned roto-molded plastic (aFe P/N 05-31912B1)
• Installation: direct bolt-on sealed system — no cutting or drilling of OEM parts
• Emissions status: not CARB exempt at this time — not legal for sale in California or for use on any vehicle registered with the California Department of Motor Vehicles.

PARTS INCLUDED

• Pro DRY S air filter (21-90083) — 1
• Roto-molded intake tube (05-31912B1) — 1
• M4 screw (03-50490) — 2

TECH RESOURCES

Additional Parts Required

• None. aFe Power specifies no additional hardware, tune or fluids for this intake — it is a direct bolt-on kit that requires no cutting or drilling of factory parts.
• Installer-supplied: basic hand tools, including a T-handle or driver for M4 Torx screws and a nut driver for the hose clamps.
• Optional service item: the Pro DRY S filter is washed and air-dried only — no filter oil is required.
• Optional accessory: aFe offers a Magnum FORCE intake system cover, P/N 54-31918-B, sold separately.

Installation

• aFe Power 51-31912 / 54-31912 installation instructions (PDF)

Notes

• Year ranges above follow aFe Power’s current installation instructions. Confirm fitment with Speed Logic before ordering.

PART NUMBER

• 51-31912

VEHICLE APPLICATIONS