"by using veporized gasoline i am trying to operate as close to the otto cycle as possible. a combustion engine that runs on fuel in its vapor form uses much less fuel , produces less polluttants because more fuel is burned and pefroms better.
I'm sorry to say it mustben, but the reasoning is flawed from the outset, specifically the statement that, "a combustion engine that runs on fuel in its vapor form uses much less fuel." A combustion engine does indeed run best when the fuel is ultimately burned as completely as possible. The ideal Otto efficiency is approached (but never reached) when heat addition approaches a constant-volume process, that is, in a practically instantaneous amount of time at firing TDC.
However, in a port-fuel injected engine, barring extremely bad design, the fuel is already completely evaporated by the time of spark ignition. I can't think of ANY modern, emissions-controlled implementation that has the mixture preparation so bad as to still have liquid fuel present during the beginning of combustion. Having so would be manifested by large quantities of soot emissions, which we know is not the case for a normally-operating SI engine.
The flawed thesis is the same case that's made by purveyors of "vapour carburetors" and their likenesses. Somehow, the fact is lost that lean combustion cannot be extended without limit, but, these people argue, is dependent only on how good the degree of fuel vapourisation is.
Granted, some improvement in fuel efficiency could be achieved by a reduction of pumping losses by some degree of dethrottling in a fully-vapourised, lean fuel-air charge. Some improvement in indicated efficiency could be achieved through a higher cycle-averaged specific heat ratio.
However, there will be efficiency losses due to the longer combustion duration of homogeneous-lean combustion that would actually cause you to deviate AWAY from a constant-volume heat addition that is defined by the Otto process. As noted above, detonation is a very real threat made more likely by lean mixtures.