Supermouse,
There are a few differences in premium mogas and ordinary mogas so I guess you need to be specific. 100MON Avgas is typically around 102.5MON and our high octane pump mogas is 88-90. RVP is variable by season but a nominal 7.5 vs 15 PSI is significant.
You can run an IO540 (not TIO) successfully on premium unleaded provided spark timing is not advanced excessively, the oil temperature and inlet air temperature are not too high and at high power output the mixture is sufficiently LEAN enough or sufficiently Rich enough.
Important NOTE: Appropriately LOP mixtures are detonation free. This is contrary to popular myth, but it is fact none the less.
Even when detonation is occurring the HP remains fairly constant, however the pressure waves around the combustion chamber do attack the thermal boundary layer driving CHT's up quickly, which self promotes more detonation, and if the pressure spikes are severe enough they attack spark plug ceramics and ring lands etc. This has to be worked hard at to achieve I might add on Avgas, and is still not easy with PULP.
Switch to a turbocharged engine and the IAT is much higher, especially without intercoolers, and with mixtures in the 30-75dF ROP range detonation is quite likely.
Lastly TetraEthyl Lead is NOT a lubricant. At all. In the minute quantity present it could not do anything even if it was a super lube, besides it turns into a salt when burned and they make crappy lubricants.
Happy to discuss this in a sensible scientific manner but we must slay a few old wives tales along the way.
