Arctic Cat C-TEC2 8000 Engine

[AndreyB]

Modern two-stroke engines are pretty cool: ECU is in charge of changing rotation direction in order to go in reverse!

Dual-Stage Injection: Slotter piston in order to inject fuel _twice_: slotted piston design allows fuel/oil mix to be injected into the crankcase area and then into the transfer ports as part of the Dual-Stage Injection design

Automatic Decompression similar to Harley? And electronic oil pump. While cable-operated throttle bodies and stepper idle air valve, weird.

Also exhaust temperature sensor.

More info https://www.arcticinsider.com/everything-you-wanted-to-know-about-the-arctic-cat-c-tec2-8000-engine/

[AndreyB]

Oh, fun thing I've learned today: two cylinder engines referring to injectors/coils as MAG and PTO.

Apparently PTO stands for power take off (the clutch side) and MAG is Magneto or generally referring to the side where the ignition/ electrical is generated.

[AndreyB]

not this engine but "how does electronic reverse work on a snowmobile"

[AndreyB]

https://snowgoer.com/news/tech-professor-flashback-push-button-reverse/30558/

When the switch is pushed, the module cuts off the ignition and the engine speed drops to approximately 550 RPM. The speed varies depending upon the engine equipped with RER. The MPEM then fires the ignition at about 60 degrees before top dead center (BTDC). Normal ignition timing is about 20 degrees BTDC. The huge advance forces the burning mixture to push the piston back down and start the engine in reverse rotation. A second trigger coil takes over and controls the ignition advance while the engine is in reverse rotation.

[gurov]

oil pump must not care then which way it's spinning., or it's splash-lubricated.

[zed65]

Two stroke

[AndreyB]

OEM ECU is definitely unusual.

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[AndreyB]

OEM ECU is definitely unusual.

Hold on, what are those blue things? Does this hint at CDI?

[Dron_Gus]

Film capacitors looks like part of high voltage supply? https://nitsuko-ele.co.jp/product-information/

[AndreyB]

is that five difference sources of A/C?!

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[AndreyB]

Neither https://rusefi.com/docs/pinouts/ArcticCat/?connector=C&pin=8C nor https://rusefi.com/docs/pinouts/ArcticCat/?connector=C&pin=9C is connected to frame GND https://rusefi.com/docs/pinouts/ArcticCat/?connector=A&pin=33A

That's the 19Ohm coil, that one produces 20v DC to feed injectors

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[AndreyB]

Similar story with fuel pump A/C coil

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[AndreyB]

Fuel pump DC

Fuel pump resistance maybe 1.2OHm

17v average?

Ohm's law seems to align with current clamp at around 20Amps

https://rusefi.com/docs/pinouts/ArcticCat/?connector=C&pin=17C

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[AndreyB]

Turns out AC CDI is easy - just SCR thyristor, huge capacitor, two diodes and two resistors. AC specifically makes it simpler by helping thyristor close.

Next step hooking this directly to my wall AC power and giving it a stress test, right?

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[AndreyB]

Made a bench test setup with wall power as source of A/C current. 500ohm / 20W to keep the smoke contained.