[serialk11r]

Ah okay. I'd just go open loop at a lower MAP if you're worried. 700mbar is not that high though, I think your engine will be fine. I really don't think burning anything up is an issue, because engines running with cooled EGR have even slower burning mixtures. The peak flame temperature theoretically increases, but you have less and slower heat release so there isn't as much heat for the piston to absorb in the first place.

It would help to raise your compression ratio to provide a blanket increase in combustion speed to compensate for the slower lean burn but I suppose that's not an option.

For my future S2k I might just use a narrowband emulator and run modestly lean to make things easy. The issue with that engine is the stock tune runs at ~13 AFR at WOT, so there's not a lot of room to lean it out for cruising, maybe 5% at best, which is incidentally about where ignition timing needs to be changed before efficiency drops.