On: Porsche's idea for a six-stroke internal combustio...

[nikanj]

You can overfill the cylinder for the first stroke, because the unspent fuel will burn on the next cycle instead of being exhausted.

High power engines exhaust a lot of unburned fuel, because you can't guarantee an exact 100% fill for the cylinder, and there's more power to be had at 120% fill than 80% fill. Oversimplified of course.

[ethbr1 → nikanj]

But you don't have an additional intake stroke, so there's limited oxygen in the second power stroke to burn.

It sounds more like they're running fuel-lean, then possibly adding more fuel before the second compression stroke.