Speed Logic Catless Race Downpipes – BMW 135i / 1M / 335i (N54)

OVERVIEW

Downpipes are a proven modification on the N54, and Speed Logic's catless race downpipes for the 135i and 335i are good for over 30 wheel horsepower and 40 lb-ft at the wheels with adequate tuning. They use a full 3" one-piece cast section at the V-band connection to the turbos, which keeps flow smooth and turbulence low where the factory pipe is at its most restrictive, and the improved flow brings a noticeably deeper engine and exhaust tone. Construction is 304 grade stainless throughout, TIG welded and argon backpurged, and every set ships with the gaskets and Grade 10 bolts, washers and nuts needed to complete the installation. All Speed Logic products carry a lifetime warranty against manufacturer defects and fitment issues.

SPECS

• Full 3" diameter, one-piece cast design at the turbo V-band entry, stepping to a 2.5" connection at the midpipe / catback
• Catless race downpipes - one for the front turbo, one for the rear turbo
• Full 304 grade stainless steel construction
• Adds 30+ horsepower and 40+ lb-ft of torque with adequate tuning
• 100% TIG welded, all welds fully backpurged with 100% argon
• Welds are not ground or polished
• Works with all stock-location turbos: OEM, Pure Turbos (Pure600, Daily Driver, High Flow), Vargas Turbos (Stage 1, Stage 2, Stage 2+), RB Turbos (Stage 1, Stage 2, Stage 2+, GFs)
• Replaces OEM BMW downpipe part numbers 18307587609 and 18307587610
• Gasket set and Grade 10 downpipe hardware included
• Fits both Left Hand Drive (LHD) and Right Hand Drive (RHD) vehicles without modification
• Catless - off-road use only, not available for sale in California or other emissions-testing states
• Includes a Speed Logic LIFETIME warranty against defects and fitment issues

PARTS INCLUDED

• (2) Speed Logic downpipes - one for the front turbo, one for the rear turbo
• (2) Downpipe gaskets
• (4) Bolts, washers, lock washers and nuts for the midpipe connection

TECH RESOURCES

Additional Parts Required

• A tune is required. These are catless downpipes, and without supporting software the car will log catalyst efficiency faults and throw a check engine light. Speed Logic supplies the MHD Super License for N54 Engine and the JB4 Tuner for N54 BMW.
• No other hardware is needed - the gaskets and Grade 10 fasteners for the midpipe connection are supplied in the box.

Installation

• No installation document is published for these downpipes. Our team is available to answer fitment questions - Request an Install Appointment to have them fitted at our Southern California facility.

Notes

• *NOTE: Speed Logic Downpipes are for OFFROAD USE ONLY and not available for sale in California and other states with emissions testing.

VEHICLE APPLICATIONS