ORIGINAL: DarZeelon
Nitro... This issue is discussed yet again.
OS recommend no more than 15% nitro and the medium #8 glow-plug, for this engine to run properly.
If you use more nitro and/or the hot A3 glow-plug, you would have to richen the mixture considerably, so the ignition would be delayed enough to prevent detonation (known as a lean-run to most people), but then you may have a soggy mid-range...
Dar, in contrast to Tower's site, the manual says "For the best performance, a fuel containing 5% to 20% nitromethane is preferable". It also recommends three plugs: A5, A3 and #8.
ORIGINAL: DarZeelon
The fact that nearly any engine can be made to run on more than the recommended maximum nitro, does not mean it is the right fuel for it.
It simply doesn't; not by a long shot.
In principle, I agree with this. However, if one discovers additional benefit from upping the nitro beyond recommended levels, this is good too. One should not be too rigidly bound by institutionalised thinking.
That notwithstanding, I still recommend running 15% in the .50 SX based on what I've seen in the field.