E85 does that even better, as the cost of being less dense. But it cools so much better you can run higher boost.
What about LPG?
And if we want LPG to be something we still have to deal with legislation, like in many countries you can't park in an underground garage with LPG.
For engines getting smaller: the LPG operation of petrol engines provides lower power output (and lower torque), so an uptick in LPG powered (dual fuel?) cars would probably mandate slightly different engines sensible (bigger ones), the market would surely adapt to it.
E85 would also be fine if it wouldn't be manufactured from intensively farmed monocultural agricultural products, which make it totally non-sustainable and non-renewable factoring in the sustainability problems of industrial agriculture (soil erosion, carbon depletion of soil, death of soil microbiome, groundwater depletion, etc)
The parking ban for LPG in closed garages is a real problem, I have faced it myself. Though it is justifiable, but then it would also be justified for the BEVs as there were cases already where (heat from) a battery fire compromised the structural integrity parking complexes, so it is a manageable risk probably, and probably mostly legislative.
They dump extra fuel to prevent knock. It's hard to melt cylinders.
> can't park in an underground garage with LPG
And yet people park. I haven't heard about an accident in the last 5 years. Maybe it could be managed by an extra detector?
LPG engines could be excellent generators (back ups or range extenders for cars and trucks). The emit less particulate matter and NOx.
I'm not sure why parking with LPG is a problem but parking with 10-20 gallons of gasoline is not?
In case of a leak there is a risk in case of a not-ventilated enough underground garage it is possible that the gas accumulates in the lower parts before it can be sensed/sniffed, and a mix of just 2.1% with air is already at risk of explosion if a spark is generated.
Security norms changed in the EU around 2001, the norm is the ECE/ONU 67-01 (though different countries may have implemented differently in the local Law) and LPG powered cars conforming to that standard are allowed (generally) to be parked in underground garages BUT only on the first underground floor and only if the garage is conforming to some (earlier) ventilation standards.
AFAIK cases of explosions/fires related to LPG car tanks are extremely rare (thanks also to the added safety measures mandated by ECE/ONU 67-01), whilst fires/explosions originated by domestic LPG use, while not common, are more common than what they should be (the tanks in themselves are generally safe, but the - often underground - pipings often are not).