# Fueling & Injection - ANyone know average specific gravity of most pump gas?

GrannySShifting
07-06-2005, 06:48 PM
Just curious :devil:

07-07-2005, 10:47 AM
Not a very ideal thing to find out.
Gasoline is a mixture of various organic compounds ( o,m,p-Xylene , Benzene, etc...) All of those compounds have chemical formulas between C6H14 and C12H26, with different specific gravities, but a good "average" compound is supposed to be C8H18. This means that molecular weight is (12.01 x 8) + (1.01 x 18) = 114.26 grams/mole

Now, an average pump gas at BP is sure different than Mobil, or Shell....

Ultimately, I can get you specific gravity (density) for each individual compound, but not a composite...unless you know the make up....

Use Density = Mass/Volume and PV = nRT formulas to calculate the rough density....but that is a very rough estimate....
I'm sure there was a study done, and it's published on the internet....

Good Luck

bigdsz
07-08-2005, 09:59 PM
92 octane = .75

onfire
07-09-2005, 09:41 PM
sunoco 100 is around 0.746

SUPRYZE
07-10-2005, 01:35 PM
Not a very ideal thing to find out.
Now, an average pump gas at BP is sure different than Mobil, or Shell....

I'm assuming these variances come from the additives added to the gasoline? The reason I say this is most gasolines are "fungible" meaning they all come from the same place. Granted most companies have there own refinering, but instead of 10 companies running 10 pipelines, they usually share 1 or 2 pipelines. They produce a product that meets certains specs and they can add it to the system. So a refinery in Texas can add 100 gallons to the pipeline, which allows them to take 100 gallons out up in New York. What makes them different is the additives package once the gasoline is removed.

DocT
07-13-2005, 11:59 PM
not too difficult, just put a drop on a refractometer and read the results...good job onfire and bigdsz...

GrannySShifting
07-14-2005, 12:09 PM
Where do you get a good quality refractometer?