OVERVIEW
The bootmod3 FlexFuel Kit for BMW F-series N55 and S55 vehicles puts the required flex fuel hardware on your car in your own driveway. The kit is entirely plug and play with the factory vehicle harness — no cutting or splicing of OEM wiring or connectors — and installs at the factory fuel hat location using the OEM fuel pump and lines.
At its core is a CANBUS-enabled Ethanol Content Analyzer (ECA) that reports real-time ethanol content to bootmod3 CustomROM. Install the kit, flash a flex-fuel-enabled bootmod3 OTS MultiMap or custom map, and the car adjusts automatically as you blend pump gas and E85 — no re-flashing between fills.
The kit is fully reversible and can be removed back to stock without a trace.
SPECS
- Mounting: factory fuel hat area, below the rear seat
- Flex fuel sensor adapter: custom 3-piece aluminum 6061 with built-in sensor bypass for obstruction-free fuel flow
- Flow optimized design: no added pressure drop at full fuel pump flow
- Sealing: all connecting points sealed with fuel-safe Viton o-rings
- Auxiliary ports: two 1/8 NPT ports for an optional fuel pressure sensor
- Ethanol Content Analyzer: CANBUS enabled, integrates with bootmod3 CustomROM, in a custom aluminum 6061 enclosure
- Electrical: Power/CANBus 4-wire harness, 100% plug and play with the BMW fuel pump controller (EKP3) connectors on N55 and S55 vehicles
- Fuel line: custom kink-free teflon braided line, plug and play with the OEM fuel hat and factory fuel feed line — no cutting and no new lines required
- Sensor: Continental flex fuel sensor
- Fitting: -6 AN fitting by Racetronix
- Designed for the OEM fuel pump and fuel lines — variations to fuel lines or pumps may not be compatible
PARTS INCLUDED
- Custom 3-piece aluminum 6061 flex fuel sensor adapter with built-in sensor bypass
- Continental flex fuel sensor with 3-wire harness
- CANBUS-enabled Ethanol Content Analyzer (ECA) board
- Custom aluminum 6061 CANBus enclosure for the ECA board
- Power/CANBus 4-wire plug-and-play harness
- Custom kink-free teflon braided fuel line
- -6 AN fitting by Racetronix
- Fuel-safe Viton o-rings
TECH RESOURCES
Additional Parts Required
- A bootmod3 tune license — required. N55: Bootmod3 Tune – BMW N55 (F-Chassis). S55: Bootmod3 S55 Tune – BMW M3 / M4 / M2 Competition.
- Speed Logic ECU Unlock Service – S55 — 2019+ S55 cars on March 2019 or later software need a bench unlock before bootmod3 can be flashed.
- A flex-fuel-enabled bootmod3 OTS MultiMap or custom map — required to use the ethanol reading.
- E85 or an ethanol/gasoline blend — the kit measures blend content; it does not add fuel system capacity.
- Rear seat removal and basic hand tools for access to the factory fuel hat, supplied by the installer.
Installation
- bootmod3 Flex Fuel Kit Installation Instructions — official bootmod3 wiki (F-Series S55/N55)
- bootmod3 official install video — F-Series S55/N55 FlexFuel Kit
- bootmod3 CustomROM guide — flex fuel setup (official bootmod3 wiki)
Notes
- VEHICLE MANUFACTURER WARRANTY AND EMISSIONS DISCLAIMER: Some items sold and/or installed by SPEED LOGIC may void portions of your vehicle’s factory warranty. Some items may not be legal for “on highway use”. SPEED LOGIC makes no guarantees to the legality of any parts used for “on highway vehicles” and accepts no responsibility for compliance with the vehicle’s factory warranty.
- X-series (X3 / X4 / X5 / X6) N55 vehicles: confirm fitment with Speed Logic before ordering.
VEHICLE APPLICATIONS
| Make | Model | Chassis | Engine | Years |
|---|---|---|---|---|
| BMW | M135i | F20 / F21 | N55 3.0L Turbo I6 | 2012–2016 |
| BMW | M235i | F22 / F23 | N55 3.0L Turbo I6 | 2014–2016 |
| BMW | 335i | F30 / F31 | N55 3.0L Turbo I6 | 2012–2015 |
| BMW | 435i | F32 / F33 / F36 | N55 3.0L Turbo I6 | 2014–2016 |
| BMW | 535i | F10 / F11 | N55 3.0L Turbo I6 | 2011–2016 |
| BMW | 535i GT | F07 | N55 3.0L Turbo I6 | 2010–2017 |
| BMW | 640i | F06 / F12 / F13 | N55 3.0L Turbo I6 | 2012–2018 |
| BMW | M2 | F87 | N55 3.0L Turbo I6 | 2016–2018 |
| BMW | M2 Competition | F87 | S55 3.0L Twin-Turbo I6 | 2018–2021 |
| BMW | M3 | F80 | S55 3.0L Twin-Turbo I6 | 2014–2020 |
| BMW | M4 Coupe | F82 | S55 3.0L Twin-Turbo I6 | 2014–2020 |
| BMW | M4 Convertible | F83 | S55 3.0L Twin-Turbo I6 | 2014–2020 |
