- Jun 7, 2020
Around where I live and worked for the pipeline, 9# was summer gasoline for areas outside the EPA compliance zones. The counties inside the zone went down to 6.8#. Winter gas is up to 15#, with no differences by county. It's quite a bit cooler up here, so we need the much higher RVP in the winter for cold starting. The takeaway is that the low RVP of 100LL isn't terribly relevent, since people with mogas STCs fly in the winter just fine on 15# gas. I wonder what the RVP of UL94 is?The difference in the vapor pressure between mogas and 100LL is not that great. As stated, in North Texas we have a boutique fuel market as we burn reformulated gasoline year round. The EPA mandated certain counties to follow this rule, and most other counties voluntarily opted in.
So our 93UL has an RVP of 7.8 or less. I think 100LL is around 5.5. The normal standard set is 9.0 psi for auto gasoline.