It depends a lot on the engine as to how much power loss you get.

If you can find engines with a high compression ratio (Webra and a few other European brands) then chances are they'll run *better* on 0% nitro than they would on 15%.

OS and Thunder Tiger 2-strokes will be pretty happy with 0% too.

Engines to avoid are hi-compression ones like the Saito and YS 4-strokes. The Saito will still run but will definitely be down on power and won't idle so well. The YS probably won't run worth a bean on 0%.

For what it's worth, we run the following engines around here on 5% nitro and they'd probably run almost as well on 0%:

TT46Pro, TT42GP, TT61GP, OS46AX/FX, SuperTigre 90, SK90, VMAR46, GMS47, GMS32.