ECU Comparison

rusEFI ECU Comparison

Every rusEFI universal ECU runs the same open-source firmware. What differs between them is how much engine you can attach, and what is already fitted on the board. This page compares all eight side by side.

For prices, store links and a short description of each board, see the Hardware overview. Unfamiliar abbreviations are spelled out in Acronyms and Terminology.

Which one do I need?

• 1 or 2 cylinders, or a small batch-fire 4 — nano. Inductive ignition only, not CDI compatible.
• Up to 6 cylinders, sequential — uaEFI. Wideband, knock and barometric sensing already on the board.
• 6 to 8 cylinders in a sealed or automotive-connector package — uaEFI 121 or super-uaEFI. Same core as uaEFI.
• 10 to 12 cylinders, dual electronic throttle — Huge or Proteus. Proteus adds an IP68 case.
• 4 cylinder gasoline direct injection — Power4GDI.

Engine capability

	nano	uaEFI	uaEFI 121	super-uaEFI	Huge	Power4GDI	Proteus	microRusEFI
Max recommended engine	1-2 cyl, 4 cyl batch	1-6 cyl	6 cyl dual throttle, 8 cyl wasted	6 cyl dual throttle, 8 cyl wasted	12 cyl	4 cyl GDI	12 cyl	4 cyl
Injector channels	via 6 low-side	6 sequential, up to 8	6 sequential, up to 8	6 sequential, up to 8	12 high-Z	4 ƒ	via 16 low-side	4 high-Z
Ignition channels	smart or dumb coils	6 sequential	smart coils	smart coils	12 logic level	4 ƒ	12 x 5 V	4 x 5 V logic
On-board igniters (IGBT)	—	expandable	expandable	expandable	—	—	—	—

Inputs

	nano	uaEFI	uaEFI 121	super-uaEFI	Huge	Power4GDI	Proteus	microRusEFI
VR (crank / cam)	1	2	2	2	3	none ƒ	2	1, VR or Hall
Hall / digital	—	3	3 ƒ	3 ƒ	5	1 ƒ	6	1
Analog inputs	5	9 + 2	7 + 2	7 + 2	13 + 2 temp	6 ƒ	11 + 4 temp	10 + 4 thermistor
Knock sensing	—	yes	yes	yes	dual channel	yes ƒ	yes	—
Flex fuel input	—	yes	—	—	—	—	—	—

Outputs

	nano	uaEFI	uaEFI 121	super-uaEFI	Huge	Power4GDI	Proteus	microRusEFI
Low-side drivers	6 total	4 above 1 A, 6 on newer	6 additional	6 additional	35 ƒ	4	16 x 4 A	2 high-current, 4 low-current
High-side drivers	—	—	1 x 2 A	1 x 2 A	—	—	4 x 12 V 3 A	—
Electronic throttle (DBW)	—	2 x 6 A H-bridge	dual	dual	4 H-bridges	1 DC output ƒ	dual	single
Stepper idle valve	—	yes	yes ƒ	yes ƒ	yes ƒ	— ƒ	yes	yes ƒ
Tachometer output	dedicated pin	configurable	configurable	configurable	configurable	configurable	configurable	configurable

No board sets a default tachometer pin in firmware, so on every unit except nano the tach signal is assigned to a suitable spare output. See the Hardware FAQ for choosing the right kind of output for your gauge.

On board

	nano	uaEFI	uaEFI 121	super-uaEFI	Huge	Power4GDI	Proteus	microRusEFI
Wideband controller	—	LSU 4.9	dual LSU 4.9	dual LSU 4.9	dual LSU 4.9	LSU 4.9	—	—
Barometric sensor	—	yes	yes	yes	yes	—	—	—
MAP sensor	—	optional	optional	optional	optional	optional	—	—
EGT input	—	optional	optional	optional	—	—	—	—
SD card logging	yes	yes	fixed	removable	yes	yes ƒ	yes ƒ	yes ƒ
CAN bus	1	up to 2	1 ƒ	1 ƒ	dual	1 ƒ	dual 1 Mbit/s ƒ	1 ƒ
Bluetooth	—	optional JDY-33	—	—	optional JDY-33	—	—	—

Physical

	nano	uaEFI	uaEFI 121	super-uaEFI	Huge	Power4GDI	Proteus	microRusEFI
Connector	Superseal 26 pin	Molex Mini-Fit Jr, 68 circuits	TE 121 pin	Superseal 120 pin	Superseal 120 pin	Superseal 68 pin	TE Ampseal 93 pin	48 pin
Enclosure	—	—	metal	—	—	—	IP68 waterproof	—
Schematics published	—	repo and gerbers	no ƒ	PDF	PDF and iBOM	PDF	repo	repo
Released	2025	2023	2023	2023	2023	2024	2020	2019

How to read this

• yes or a number means the feature is on the board as sold.
• optional means the part is not fitted by default and has to be soldered on.
• — means the board does not have it.
• ƒ marks a value established from the firmware rather than from a board page, because the board page does not state it. Each one is listed below.

Sources

Values come from the board's own page on this wiki, from the hardware table on Hardware, or from that board's configuration in the rusEFI firmware. Nothing here comes from marketing material or a third-party site.

Values marked ƒ and where they came from:

Value	Source in rusefi/rusefi
uaEFI 121 has CAN	boards/hellen/uaefi121/connectors/uaefi121.yaml — pin 82a CAN bus high, pin 83a CAN bus low
Power4GDI has CAN	boards/hellen/alphax-4K-GDI/connectors/gdi-B.yaml — pin 15B CANH, pin 16B CANL
super-uaEFI has CAN	boards/hellen/super-uaefi/board_configuration.cpp — canTxPin = MM100_CAN_TX
microRusEFI has one CAN	boards/microrusefi/board_configuration.cpp — canTxPin set, can2TxPin absent
Proteus has two CAN	boards/proteus/board_configuration.cpp — canTxPin and can2TxPin both set
Power4GDI has no VR input	boards/hellen/alphax-4K-GDI/connectors/gdi-B.yaml — no reluctor pins defined
Power4GDI injector and ignition channels	board_configuration.cpp — injectionPins[0..3], ignitionPins[0..3]
Power4GDI, Proteus, microRusEFI SD card	board_configuration.cpp — isSdCardEnabled = true
Power4GDI knock	board ships a knock_config.h
Power4GDI, uaEFI 121, super-uaEFI Hall and analog counts	that board's connectors/*.yaml
Huge low-side count	board_configuration.cpp — getBoardMetaOutputsCount() is 41, low-side is total minus 6
Stepper idle on uaEFI 121, super-uaEFI, Huge, microRusEFI	DC output count in board_configuration.cpp, applied against the rule on Stepper Motor that two H-bridges drive a 4-wire stepper
uaEFI 121 schematics	the uaEFI 121 FAQ states there are no plans to make it open source hardware

Two notes on method, so the numbers are not over-trusted:

• injectionPins[] in a board config is that board's default engine setup, not its capability. Huge sets only four injector pins by default despite having twelve channels. Channel counts on this page therefore follow the board pages; firmware was used for counts only where the board page is silent.
• Each source counts analog and Hall inputs differently. The connector files count every analog pin, including on-board MAP, knock and battery sense; the board pages count user-available inputs. Where they disagree the board page figure is shown, since that is the published specification.