The Cylinder Trims menu is used to configure the engine firing sequence, ignition output assignment, injector sequencing, and tachometer behavior.
This section allows both quick automatic setup using the built-in calculator and full manual configuration for advanced or custom engine setups.
The Quick Settings section provides an automatic calculator that simplifies engine configuration by generating firing angles and assigning ignition outputs automatically.
Defines the engine operating cycle type.
| Option | Description |
|---|---|
| 2-Stroke | Each cylinder fires once every crankshaft revolution |
| 4-Stroke | Each cylinder fires once every two crankshaft revolutions |
| 🌀 Wankel / Rotary | Rotary engine mode for Mazda-style rotary engines |
When the Wankel option is selected, the ECU adjusts its synchronization and firing calculations to match the operating characteristics of rotary engines.
The RM-Primis is compatible with Full sequential and also 2 different methods of wasted spark on Wankel engines as found on the RX7's
This mode is intended for:
Unlike traditional piston engines:
💡 Always ensure the trigger pattern and ignition output configuration are correctly configured for your specific rotary engine setup.
Specifies the number of cylinders in the engine.
Example:
The ECU uses this information to calculate firing intervals and synchronization.
The firing order calculator automatically generates a common linear firing sequence and distributes ignition outputs accordingly.
⚠️ This setting itself is NOT stored inside the ECU.
Only the following are saved:
This allows the generated configuration to be fully customized afterward if required.
Enables automatic ignition output assignment for Wasted Spark systems.
In a wasted spark system:
This setup is commonly used on:
Automatically configures ignition outputs for Wasted Coil-On-Plug systems.When this option is selected the engine will always start in wasted spark/cop even if configured for Full Sequential and after a few cycles it will move into full sequential, this allows the engine to start much faster.
⚠️ This might cause the CAM angle to display a different value until it moves into Full Sequential but doesn't change anything else.
In this configuration:
This is often used when:
Enables distributor-based ignition mode.
When enabled:
This mode is commonly used on:
The Advanced Settings section allows full manual control over cylinder timing and output assignments.
This column defines the crankshaft angle at which each cylinder fires.
Example for a 6-cylinder engine:
| Cylinder | Firing Angle |
|---|---|
| Cyl 1 | 0.0° |
| Cyl 2 | 480.0° |
| Cyl 3 | 240.0° |
| Cyl 4 | 600.0° |
| Cyl 5 | 120.0° |
| Cyl 6 | 360.0° |
Unused cylinders remain set to 0.0°.
💡 On a 4-stroke engine the full engine cycle equals 720° of crankshaft rotation.
The injector checkboxes determine whether fuel injection is enabled for each cylinder.
In a sequential injection setup, each injector is synchronized according to the configured firing angles.
This section defines which ignition output fires each cylinder.
Example:
| Cylinder | Ignition Output | Angle |
|---|---|---|
| Cyl 1 | IGN 1 | 0° |
| Cyl 2 | IGN 2 | 480° |
| Cyl 3 | IGN 3 | 240° |
The ignition outputs do NOT need to follow a linear order.
You may freely assign:
As long as the firing angle matches the correct engine sequence.
It's also possible to run Engines up to 12 cylinders with paired injectors/coils and we can manually configure the way the outputs are fire to match the way the engine is wired, below shows a 8 cylinder wasted-cop and batch fire configurations. As you can see on the image below the same ignition output is fired in two different angles, in situations like this is recommended to configure the ECU to fire the outputs in sequence and phisically wire the injectors and coils as per firing order in pairs.
Some RM Racing plug-in adapters support multiple vehicle applications using the same hardware platform.
Because of differences between OEM harness pinouts, ignition outputs may not always follow a simple sequential pattern.
Instead of:
1 → 2 → 3 → 4
The ECU may use:
1 → 2 → 5 → 4
This is completely normal and may occur because:
💡 Always follow the specific adapter documentation or base map configuration for your application.
The Tachometer section configures the tachometer output signal behavior.
Defines the tachometer output signal type.
| Option | Description |
|---|---|
| Dwell | Simulates ignition coil charging behavior |
| 50% Duty Cycle | Standard square wave tachometer signal |
✅ The 50% Duty Cycle setting is the most commonly used configuration for aftermarket dashboards and OEM tachometers.
Defines the cylinder count used for tachometer calculations.
This must match the actual engine cylinder count to ensure accurate RPM readings.
This option must be enabled when the engine is operating in Wasted Spark mode.
When enabled:
⚠️ If this option is not configured correctly, the tachometer may display incorrect RPM values.