1999-2017 (priority focus 2004-2016)

Harley-Davidson Twin Cam (Dyna, Touring, Softail)

The Twin Cam engine is the natural entry point for Pistonix. Original Delphi ECMs accept only Power Vision/TTS-style flashes with vendor-locked maps. There is no official support for custom boost, beyond-basic nitrous, or staged secondary injectors. Pistonix Forge replaces the original ECM while keeping the stock connector and harness, with basemaps ready for Twin Cam 88, 96 and 103 ci, with or without big-bore, slip-on or full-system exhaust.

Alternatives: Pistonix Apex , Pistonix Quarter

Electronics

What is inside.

Crankshaft: Variable reluctance (VR) sensor, sinusoidal AC signal, 2-wire.
Trigger wheel: 32-2 trigger wheel (32 nominal teeth with 2 missing for TDC reference).
Knock sensor: OEM uses ion-sense (ionization voltage on the spark plug). Pistonix Forge supports an aftermarket Bosch piezo knock sensor as a robust alternative.
Coils: Two separate coils, one per cylinder, no internal igniter (dumb coils). Driven via IGN1A smart coil drivers or external igniter.
Ride-by-wire: No — mechanical cable throttle. Simplifies throttle control.
HDLAN: No — internal communication is J1850 VPW. Fewer integration barriers than Milwaukee-Eight.

Practical notes

What you need to know.

45° V-twin geometry handled in firmware: 315°/405° firing order, asymmetric scheduler native to the decoder.
Cam reference is optional: post-2004 Twin Cam can skip the cam sensor; firmware syncs in 1-2 engine revolutions.
Bosch LSU 4.9 wideband sensors (2 units, one per bank) are plug-and-play.
OEM Delphi ECM connector pinout is well documented — adapter harness is straightforward.

Typical builds

Where we have seen it run.

Stock + slip-on

Keeps OEM pistons and cams, swaps only the exhaust. Pistonix Forge with the "Stock + Slip-On" basemap.

Big-bore 96→103 ci

Larger pistons, street cams. "Big-Bore Street" basemap with adjusted VE map.

Low-boost turbo

Up to 8 psi, stock injectors. Pistonix Forge with PWM boost control and a basic wastegate.

Single-stage NOS

Up to ~50 hp on the bottle, single stage. Native support.

Pistonix Garage

Basemaps ready for this platform.

Official tunes distributed via Pistonix Garage. Filter by configuration when loading from the Tuner desktop.

Twin Cam 88 Stock Baseline (2007) 2007
stock Published on Jun 11, 2026
Twin Cam 124 Big-Bore Drag (io_channels example)
big-bore-drag Published on Jun 11, 2026

Waitlist

Be the first to know.

Pistonix is under active development. Sign up for product updates, early basemaps, invites to ride at Milwaukee Garage Drag Racing events, and priority on the first batch of Pistonix Forge.

Monthly roadmap and firmware updates
Invite to pre-sale tuning sessions
Priority on the initial Pistonix Forge batch
Early access to per-engine basemaps