3SGTE
ST215W
Premium,MVM
join:2000-11-23
there
clubs: | reply to Jim Gurd
Re: Ethanol in gasoline
Dumb question perhaps, but it is my understanding that the higher the RVP#, the greater the ease with which the gasoline can evaporate.
Have I got that the right way round?
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Jim Gurd
Premium
join:2000-07-08
Plymouth, MI
 ·Comcast
| Yes, that's correct. I believe conventional gasoline has a RVP of 9.0 (and higher than that in the winter to allow easier starting in cold weather). Adding even a small percentage of ethanol causes the RVP to rise significantly.
One advantage of low RVP gasoline is that it reduces the chances of getting vapor lock in hot weather. It is less volatile and evaporates much more slowly (and therefore pollutes less from evaporative losses). In the winter the RVP must be increased in order for the gasoline to vaporize properly so you can get the engine started.
One interesting thing I read was that gas companies must run their tanks to almost dry before switching over to low RVP gas. Even a small amount of regular in the tank will cause the low RVP fuel to lose its low RVP properties. They run them virtually dry before making the changeover. This is one reason for price spikes during the conversion from winter gasoline to summer gasoline.
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Jim Gurd
Premium
join:2000-07-08
Plymouth, MI | Here is a map of the boutique fuel requirements nationwide.
»www.mobil.com/USA-English/GFM/Fi···_Map.pdf |
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joako
Premium
join:2000-09-07
/dev/null
 ·AT&T U-Verse
| 7.8 RVP would also be no ethanol?
No wonder gasoline in South Florida is about $0.25/gallon more than the rest of the state.
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Jim Gurd
Premium
join:2000-07-08
Plymouth, MI
·Comcast
| said by joako  :7.8 RVP would also be no ethanol? No wonder gasoline in South Florida is about $0.25/gallon more than the rest of the state. Not necessarily. It just means it's cheaper to make the gasoline without ethanol. If ethanol is required it will make the base gasoline more costly to produce in order to meet the RVP requirements. El Paso, Texas requires 7.0 RVP gas with ethanol.
Unfortunately if you live in Florida all of your gasoline will be diluted with ethanol by 12/31/2010.
»www.fueltestkit.com/florida_etha···e10.html
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