Applications Mazda 13B-MSP
Draft. Trigger offset has not been confirmed on a running Race Core install. Pins marked TBD are unknown — do not guess them. A wrong decoder or firing order can destroy the engine.
Mazda 13B Renesis (RX-8)
RX-8 Renesis. Two rotors, side ports, leading and trailing plugs, oil metering, primary and secondary injectors. The rusEFI trigger list says 36-2-2-2 might match some RX-8 installs. That is a maybe. There is no Renesis-specific row. Do not copy the FD 13B-REW CAS settings or the FD description of leading plugs on the intake side — Renesis ports are in the side housings and the plug positions are not the FD layout.
Recommended: Race Core F7, engine type rotary, 2 rotors. Four ignition outputs and four injector outputs is the common Renesis load. Trailing split is a rotary setting. A 4-cylinder wasted-spark map is the wrong way to fake it. Read the 13B-REW note for the rotary firmware idea, then log this trigger separately.
Status: draft. Trigger offset has not been confirmed on a running Race Core install.
- Cylinders: 2 rotors
- Displacement: 1308 (2 × 654) cc
- Firing order: Front leading → rear leading, trailing split in software
- Orientation: Front rotor toward the radiator, rear toward the gearbox. Label leading and trailing from the factory loom. Do not reuse the FD intake-side / exhaust-side sentence.
Variants
| Variant | Years | Trigger | Notes |
|---|---|---|---|
| 13B-MSP RX-8 | 2003–2012 | Eccentric-shaft pattern. 36-2-2-2 only if the log matches | Side ports, no sequential twin turbo. Four injectors on the common setup. Oil metering is not an injector. |
Recommended pin assignment (Race Core F7)
Pins below are the library default Race Core F7 map — the same AMPSEAL landings as the verified 1UZ-FE, 2JZ-GTE and LS1 notes. Core EFI V4 and Micro Core cavity numbers are TBD. If a pin is not in this table, it is TBD. Do not guess a spare.
| Pin | TunerStudio | Function |
|---|---|---|
| B10 | Digital 1 | Eccentric-shaft sensor, Hall, or VR 1 if the sensor is 2-wire |
| B1 | Digital 2 | Second track, if the sensor has one. Not a four-stroke cam |
| A3 | Lowside 1 | Front primary injector |
| A15 | Lowside 2 | Rear primary injector |
| A4 | Lowside 3 | Front secondary injector |
| A16 | Lowside 4 | Rear secondary injector |
| A35 | Ign 1 | Front leading coil |
| A34 | Ign 2 | Rear leading coil |
| A22 | Ign 3 | Front trailing coil |
| A33 | Ign 4 | Rear trailing coil |
| A8 | Lowside 9 | Oil metering, same landing as the FD 13B-REW draft. Confirm the output on the lid. Not a stepper |
| C20 | Analog Temp 3 | CLT |
| C30 | Analog Temp 2 | IAT |
| C13 | Analog Volt 1 | MAP 0–5 V |
| C24 | Analog Volt 2 | TPS 1 |
| C34 | Knock 1 | Knock |
| A20 | Lowside 10 | Fuel-pump relay coil |
| A21 | Lowside 12 | Main-relay coil |
| A12 | Lowside 15 | Radiator-fan relay coil |
| B17 / B16 | CAN 1 H / L | Dash / wideband |
| B18 | Battery Sense | Ignition-switched 12 V (5 A fuse) |
| B23 | +12 V MR | Main-relay 12 V into ECU |
| A17 A18 A24 B14 B19 B20 | Power GND | Engine block → battery − |
| C9 / C21 / C32 | 5 V Sens 1 | MAP, TPS, pedal 1 |
| C1–C8, C29, C31 | Sensor GND | 0–5 V and thermistor returns |
Trigger
Log the eccentric-shaft sensor before you select a mode. If, and only if, the composite matches 36-2-2-2, that is the decoder to try. If it does not, stop. Do not select the FD CAS from memory.
Crank
| Sensor | On the eccentric shaft. There is no crankshaft. |
| 36-2-2-2 | Only after the log shows that pattern. The rusEFI list says “might”. |
Cam
| Rotary | No camshaft. A second track is a home pulse, not a piston-engine cam. |
TunerStudio
| Setting | Value |
|---|---|
| Engine type | Rotary, 2 rotors |
| Trigger / wheel type | 36-2-2-2 only if the log matches. Otherwise unnamed until logged |
| Use only rising edge | VR: typically yes on MAX992x. Hall: as logged |
| Firing order | Leading pair, then trailing split. Not 1-3-4-2 |
Offset: Timing light on the front leading plug, fixed timing, then move offset. Trailing split stays at zero until leading timing is true.
Injection
Primary and secondary per rotor, four high-Z injectors on the common RX-8. If the car has more than four, the extra pins are TBD. Staged injection is a rotary fuel feature, not a second engine.
| Oil metering | Lowside 9 (A8) only as on the FD draft, and only if the pump is a solenoid load that a 4 A low-side can hold. Do not pulse it as an injector. |
Ignition
Four outputs: front leading, rear leading, front trailing, rear trailing. Logic coils or igniters. Trailing is a split, not a wasted-spark pair. Dwell 2.0–2.5 ms on a logic coil, then check temperature. Leading and trailing coils are different heat cycles — set them on purpose.
| FD plug layout | Do not copy it. Label this loom. |
Idle
RX-8 idle is often DBW. F7 H-bridges and the ETB / APP notes. If this car is cable, the idle valve pin is TBD. Oil metering must not be moved onto the H-bridges unless you have proved it is a stepper, and then you lose DBW.
First start
- Load the matching variant configuration in TunerStudio before the harness is live — injectors and coils stay disconnected until the decoder is confirmed.
- Fuel pump fuse out. Coils unplugged or spark outputs disabled. Crank. Open Diagnostics → composite / high-speed logger.
- Confirm crank teeth are even, the missing-tooth (or named pattern) is a single clean gap, and cam is one pulse per two crank revolutions for sequential four-stroke.
- RPM during cranking should sit in the 150–350 rpm band. 0 rpm or 12,000 rpm means the decoder is lost — polarity or wheel type, not offset.
- Lock timing to a fixed 10° (idle control off). Timing light on cylinder 1. Change trigger offset until the damper agrees with 10°.
- Recheck at ~3,000 rpm. If timing walks with RPM, it is VR polarity, a delayed Hall, or the wrong decoder — not offset.
- Enable spark. Confirm a healthy burn (timing light or plug colour) with fuel still disabled.
- Enable fuel. Prime, then crank. Catch the first idle on a rich-safe VE, then lean toward stoich at idle.
- Only then enable closed-loop idle, VVT, boost and traction. A base map is a starting point, not a dyno tune.
A base map is a starting point, not a dyno tune.