Engine · Mazda

Mazda rotary: what the engine asks of an ECU

Page data last updated 2 October 2026

A rotary has rotors, not cylinders, and an eccentric shaft instead of a crank, so the usual cylinder and cam questions do not apply. What matters is the injectors per rotor and the leading and trailing ignition outputs.

The variants differ on both.

Where this comes from

Some items on this page are cited from Wikipedia and from ECU manufacturers such as Haltech, not from the engine's maker. Each row names its source, and a † marks a row that is crowdsourced. Always check your specific sensors and manuals where you have them.

A figure like 58x is pulses per crank revolution from one sensor. It is a rate, not a sensor count, and it does not say whether the sensor is VR or Hall. The planner reads sensor type, cam sensor count and variable cams from the cited text. Where the text does not settle one, the row says so: check your sensor.

Variants

13B-REW (FD RX-7)

Engine
2 rotors1 †
Aspiration
Twin turbo1
Fuel injection
Port injection, sequential †
Ignition
leading+trailing (4 plugs, 2/rotor), dumb coils (external igniter needed)2
Crank trigger
eccentric-shaft CAS (crank equivalent)2
Cam trigger
n/a2
Cams and variable timing
No camshafts1 †
Firing order
per-rotor: leading then trailing (no cylinder firing order) †
Factory ECU
Mazda1
Notes
A rotary: rotors, not cylinders, and no cams. Leading and trailing coils per rotor, so four ignition outputs. The coils are dumb and need an external igniter. Staged port injection (primary and secondary per rotor, four in total). Sequential twin-turbo. The eccentric-shaft CAS is reluctor (VR). The rotors sit 360 degrees apart.2

† Crowdsourced. This figure comes from builder and parts-supplier pages, not from the engine's maker or an ECU manufacturer. Treat it as a lead, then check your specific sensors and manuals.

How the planner reads the trigger text

Eccentric-shaft sensor type
VR (reluctor)

Wire-in ECUs that cover it: 23 as they come, 23 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 23
Fits with add-ons 23

Plan a build around the 13B-REW (FD RX-7)

13B-MSP Renesis (RX-8 manual, 6-injector)

Engine
2 rotors1 †
Aspiration
Naturally aspirated †
Fuel injection
Port injection, sequential †
Ignition
leading+trailing (4 plugs, 4 coils), smart coils (igniter built in)2 †
Crank trigger
eccentric-shaft CAS (crank equivalent)2
Cam trigger
n/a2
Cams and variable timing
No camshafts1 †
Firing order
per-rotor: leading then trailing (no cylinder firing order) †
Factory ECU
Mazda1
Notes
Naturally aspirated rotary. The manual car has three injectors per rotor (six in total, three-stage: primary 1 at 290, primary 2 at 380, secondary at 380). Four plugs and four smart coils (internal igniter, direct-fire).2

† Crowdsourced. This figure comes from builder and parts-supplier pages, not from the engine's maker or an ECU manufacturer. Treat it as a lead, then check your specific sensors and manuals.

How the planner reads the trigger text

Eccentric-shaft sensor type
VR (reluctor)

Wire-in ECUs that cover it: 18 as they come, 27 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 18
Fits with add-ons 27

Plan a build around the 13B-MSP Renesis (RX-8 manual, 6-injector)

13B-MSP Renesis (RX-8 auto, 4-injector)

Engine
2 rotors1 †
Aspiration
Naturally aspirated †
Fuel injection
Port injection, sequential †
Ignition
leading+trailing (4 plugs, 4 coils), smart coils (igniter built in)2 †
Crank trigger
eccentric-shaft CAS (crank equivalent)2
Cam trigger
n/a2
Cams and variable timing
No camshafts1 †
Firing order
per-rotor: leading then trailing (no cylinder firing order) †
Factory ECU
Mazda1
Notes
Naturally aspirated rotary. The automatic has two injectors per rotor (four in total, two-stage: primary 290, secondary 480). Four plugs and four smart coils (internal igniter, direct-fire).2

† Crowdsourced. This figure comes from builder and parts-supplier pages, not from the engine's maker or an ECU manufacturer. Treat it as a lead, then check your specific sensors and manuals.

How the planner reads the trigger text

Eccentric-shaft sensor type
VR (reluctor)

Wire-in ECUs that cover it: 18 as they come, 27 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 18
Fits with add-ons 27

Plan a build around the 13B-MSP Renesis (RX-8 auto, 4-injector)

20B (Eunos Cosmo 3-rotor)

Engine
3 rotors1 †
Aspiration
Twin turbo †
Fuel injection
Port injection, sequential †
Ignition
leading+trailing (6 plugs), dumb coils (external igniter needed)2
Crank trigger
eccentric-shaft CAS (crank equivalent)2
Cam trigger
n/a2
Cams and variable timing
No camshafts1 †
Firing order
per-rotor: leading then trailing; 3 rotors 120deg apart2
Factory ECU
Mazda1
Notes
A three-rotor rotary. Leading and trailing coils per rotor, so six ignition outputs. The coils are dumb and need an external igniter. Rotaries run no conventional knock detection, so there is no knock input. Staged port injection (primary and secondary per rotor, six in total) with high-impedance port injectors. Sequential twin-turbo. The eccentric-shaft CAS is reluctor (VR).2

† Crowdsourced. This figure comes from builder and parts-supplier pages, not from the engine's maker or an ECU manufacturer. Treat it as a lead, then check your specific sensors and manuals.

How the planner reads the trigger text

Eccentric-shaft sensor type
VR (reluctor)

Wire-in ECUs that cover it: 22 as they come, 14 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 22
Fits with add-ons 14

Plan a build around the 20B (Eunos Cosmo 3-rotor)

Pairing the engine with a gearbox? BoxSelector has the ratios for the boxes that bolt up to it, and works out road speed and tyre size before the money goes: gearbox ratios.

Sources

  1. Wikipedia: Mazda Wankel engine Wikipedia · Displacement, 13B-REW, lead
  2. Haltech: Tuning rotary engines Haltech (ECU maker) · Ignition Wiring, Ignition, Crank Sensor, OEM Ignition Coils, Injection System, OEM Injector Flow Rates, Firing Order

Always verify against the manufacturer's manual and your tuner before wiring.