What is the firing sequence of the 2.0 boxer? Is it 1-4-3-2 like other boxer engines? The pictures of the pistons that I've seen in Subaru marketing material has the pistons all crazy-like in an offset pattern, but the physical properties of the engine would seem to make a symmetric firing pattern more effective: one piston on the "suck" cycle, and the one just opposite of it is on the "bang" cycle, while the other two are on "blow" and "squish", respectively. But like I said, the marketing pics show the pistons (albeit not actually inside the engine at the time) in an offset pattern, where no two are doing quite the same thing at the same time. Anybody know?

I've seen it like that before. I figured it was like that for a few reasons....

A) it's a distributorless ignition, meaning the computer controls the advance/retard of the igntion timing.

B)Top end isn't the focus of the impreza engine, so by kind of 'overlapping' the conventional 2 up 2 down cycle you'll get a more torquey, rev happy motor. Mainly so, b/c it'll take that much less time to get another piston on the 'bang' stroke.


This is all that i've theorized in the past 11 minutes since you brought it up...lol.

Factory firing order: 1-3-2-4

1324? Doesn't that set up an imbalance? Or do I have my piston numbers wrong?

I think you have your numbers wrong, I got the firing order off a Subaru dealership website.