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Boiling Point of Gasoline?

53K views 5 replies 4 participants last post by  001mustang 
#1 ·
Does anyone know how too find the current boiling point of gasoline from any supplier?
 
#2 ·
001mustang said:
Does anyone know how too find the current boiling point of gasoline from any supplier?
Take 1 gallon of gasoline, put in a tin with a lid on it,put it over a butane burner and stand next to it and light it and time it.Get back to us would you??? reminds me of what are the last words of a *******, here, hold my beer and watch this.
Seriously, who would know that?
:D :D
 
#3 ·
001mustang said:
Does anyone know how too find the current boiling point of gasoline from any supplier?
The following was obtained HERE. It is relatively dated, but will give some indication.


4.10.1 Vapour Pressure and Distillation Classes.
6 different classes according to location and/or season.
As gasoline is distilled, the temperatures at which various fractions are evaporated are calculated.

Specifications define the temperatures at which
various percentages of the fuel are evaporated. Distillation limits include maximum temperatures that 10% is evaporated (50-70C), 50% is
evaporated (110-121C), 90% is evaporated (185-190C), and the final boiling point (225C). A minimum temperature for 50% evaporated (77C), and a maximum
amount of Residue (2%) after distillation. Vapour pressure limits for
each class ( 54, 62, 69, 79, 93, 103 kPa ) are also specified. Note that the
EPA has issued a waiver that does not require gasoline with 9-10% ethanol to
meet the required specifications between 1st May - 15 September.
END (Bold face is mine)

You will notice the figure 225 degrees C (about 425 deg. F) given as the boiling point- other sites place a wide range of 100-400 deg F. The exact boiling point will change w/altitude and the time of year- gasoline is formulated w/different properties depending on the temperature and geographical location.

If I were to take a WAG, I'd say that you're gonna be close at 375 degrees F.
 
#4 ·
I have seen those specs and have taken note that 10% ethanol mix has a waver from those specs. I will at least try to buy gas w/o ethanol since I don't have any data for that mix. I am aware that gasoline is mixed more volatile in the winter but don't know when the mix is varied. I have noticed that my 64 1/2 289 mustang has experienced carb bowl evaporation post hot stop this year and I never noticed that before; perhaps I was running a winter blend that tank. I am not aware of any manufacturer publishing current gasoline properties. Of course the glass fuel filter post fuel pump in my 67 must lets me see when gasoline is boiling during hot idle. I want to minimize evaporation loses of a volatile gasoline to improve fuel economy and starting post hot engine shutdown. I have taken several steps to reduce 67 underhood temps and I maintain engine temps of about 190F-200F during all conditions. I have noticed less fuel boiling in the glass fuel filter post fuel pump. The car starts faster post hot shutdown. The engines runs good in hot stop and go traffic. The engine no longer stumbles at 4500RPM WOT post hot idle. I still see the fuel boiling sometimes, to a lesser extent, when the fuel pump housing is about 140F.
 
#5 ·
Gasoline does not have a single boiling point, it is a compound liquid and different fractions boil at different temperatures...hence the wide specification.
 
#6 · (Edited)
I agree, different fractions boil at different temps. I see the gas boiling in the glass fuel filter imediately down stream of edelbrock diaphram fuel pump during hot idle when the pump housing is only 140F. The pressure measures about 5psi accoring to my gauge (gauge is not proper range). My pump does not hold pressure very long after shutdown (few minutes at most). Looks like the pump is cavitating during the low flow conditions. I don't want to add a recirculation line to increase flow thru pump. Is it typical for diaphram pumps to cavitate gasoline during low flow conditions at about 140F?
 
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