HYPERSLED ENGINES: What’s With Cat’s New 800?

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We got some flak for not giving enough info on the 2020 Arctic Cat 800 twin a couple of weeks ago. Some of our keen-eared readers and viewers (yes, we read your feisty retort, Jamie) pointed out we weren’t giving the right details on the new, revised 800 Cat is offering for the upcoming model year.

Frankly, unearthing particulars on this high-profile change has been like sifting though a South American archeological dig in search of proof of the existence of a Yeti!

Rather than focus on the “why” behind the change to the 800 (this info is even harder to get than the other), we’ll try to spill what we’ve learned about the “what”.

First, although the 2020 800 engine is still referred to as a CTEC-2 engine, it no longer uses the classic Dual Stage Injection system found on the DSI 600 and the 2019 800.

Just to refresh, the concept behind Dual Stage or “Slot Injection” centers on a vertical slot being cut into the side of the piston on the injector side.

The slot is exposed to the fuel injector long enough to allow gas to be sprayed under the piston and onto the bottom end rod bearings and upper piston pin on each cylinder.

At high RPM as more fuel is required, on the power stroke, the fuel is injected through the slot and travels up from the crankcase via the transfer ports to the top of the piston and secondly, is injected directly onto the top of the piston as it passes by the slot. Pinpoint oil distribution lubes the bottom end bearings.

This injection design has proven to be extremely reliable on the 600 and it was pretty much a no-brainer Cat would use the same design on the 800 – and they did.

However, for 2020, Cat has gone with a different design altogether for the 800. This year, the pistons do not have slots and the injectors are mounted inside the transfer ports. Engine programming is set up so the fuel is injected in sequence during the power stroke so the fuel is jetted to the top of the piston where it’s ignited and the crankcase is left relatively free of unburned gasoline.

Depending on how Cat has chosen to program its ECU, you could call this new set-up Semi-Direct Injection or SDI. As you know, Polaris uses SDI on all of its performance 2-strokes including the 600, 800 and 850. This is where the guessing will begin, ladies and gentlemen.

We’re wondering if Arctic Cat, knowing the new standard in big-inch engines was now 850ccs, did the engineers face challenges with an SDI 850 design and instead opt to build an all-new SDI 800 version with the intention to bring out a new SDI 850 a couple of models years down the road?

Based on what we’ve been able to find out so far, we’ll likely never know. However, apparently the performance of the 2020 800 is excellent and in no way gives quarter to the SDI 800.

Kent Lester
Kent Lester
Kent Lester is Co-Publisher of SUPERTRAX Magazine and a regular contributor to this website.

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