Pro Stock John

iTrader: (34)

Anyone know the difference in the mixture? Is 93 octane from Amoco still 93?

Also, with the cooler winter air (20-45F), is it okay because we need less octane with colder air?

WILWAXU

iTrader: (6)

Well.. if the octane rating is 93, I believe it would have to be at least that or higher.

Patman

Winter gas has more additives in it like gas line antifreeze, and summer gas had additives to help aid starting on hot summer days but no matter what, it'll still be at least 93 octane. By law, if a pump says 93, that's the minimum it has to be. Performance shouldn't change with either gas.

joghotrod

Hi John, I just talked to the ExxonMobil Refinery super and he said the only thing they change from summer to winter is the vapor pressure. If the pressure is too low the gas will not vaporize in the winter. They control the vapor pressure by adding or subtracting butane in the gas. I hope this helps. Jimmy

LEO

iTrader: (3)

John, I've got a Citgo station under construction right now and I believe the distributers do change their blends in summer/winter. If it says 93 it's 93. Unless some bitch of an owner was being really unscrupilous and filled his entire system with reg. rather then putting the proper mitures in the tanks. If you believe this has happened send out a sample of your gas to a lab and report it to BP/Amoco headquarters - they'll get the bastard.

FastAl

Depends on what your winter gas is! Here they add MTBE (or is it MBTE?) to the gas. There is a difference for me getting gas at the gas station in BFE outside of the additive region and getting it closer to Denver.

The Alchemist

iTrader: (19)

Just to clarify a few points.

The difference is most definitely the vapor pressure, but it has more to do with summer months than the winter. If the vapor pressure is not regualed during the summer, you run the risk of vapor lock. During the winter, there are no regulations when it come to v.p.

This used to be my biggest headache in the spring time when I was a qc chemist for Sunoco. We'd have to make certain that the rollout of l.v.p. occurred completely by May 15 which included any and all storage tanks.

LEO

iTrader: (3)

This is the reason why we pay more for gas in the summer months.

Pro Stock John

iTrader: (34)

Also, how much does gasoline weigh, 6, 7 or 8 lbs per gallon?

LEO

iTrader: (3)

I believe it is right around 7lbs. per gallon.

Pro Stock John

iTrader: (34)

Since we have some momentum here, do gas stations buy gas from the same companies?

I pretty much just run Amoco Ultimate since it's always clear.

red ws6 99

Well were I live (small town 60000 people) one truck comes and fills up many different stations an all have different brands of gas. Not sure if thats the case in larger cities but it definetly does happen.

Gary

LEO

iTrader: (3)

Okay John I guess I'll give away a little trade secret here. Many companies ie. Mobil, Marathon, Citgo, Phillips, etc...allow stations to buy unbranded gasoline, it is not always cheaper so sometimes a Mobil station may buy Shell gas, gas prices vary day to day. Unbranded gasoline IS NOT of lesser quality, let me get that out of the way first. Companies like Shell and BP/Amoco have their own brands and add detergents to their formulation - so they can tell you how much better their gas is, but the difference is pretty negligble to tell you the truth.

Pro Stock John

iTrader: (34)

I have heard that before, that's why Slow 'hoe gets Citgo on Cumberland.

LEO

iTrader: (3)

Alot of the difference people feel in their cars with different brands of gas has to do with simple M-A-R-K-E-T-I-N-G.

If your car is adversely affected after going to a station and filling up with premium octane fuel, it would more likely be due to that particular gas station having a leak in their fuel tanks, which may cause water to mix with the gas or you filled up when the tanks were really low and you sucked up the sediment in the tanks.

02 SOM WS6

Also, all through the year the formulation can change a little at any time. I work at the biggest BP (old Amoco) refinery in the states,in Texas City, TX. When market prices change for certain components, they may take them out of gasoline blending and sell them or put them in something else. They can then make up the octane with something else, toluene, xylene, alkylate, isomerate, all sorts of different products. The advertised octane will change by no more than 1 or 2 tenths of a point. Usually, Ultimate is right around 93.1 to 93.2 octane. Selling extra octane costs money. The RVP(Reid Vapor Pressure) specs do change from winter to summer as has been stated above. One more thing, the formulations change from one area of the country to another as some cities are getting lower sulphur formulations and so on. I believe Atlanta has lower sulphur gasoline from us. Hope this helps a little, I have been consuming some delicious wine tonight.

Later
Les

BIGBOS

I never buy from the Citgo around me, its got 10% ethanol in the gas...I assume its not as good as the mobil 1 93 octane I usually use, I put in a drop or two of 100 every now and then... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

LEO

iTrader: (3)

BOS, you'd better read my posts again - what makes you think the Mobil station isn't buying from the same distributor? My partner is also a distributor of gasoline, he sells to Citgo, Mobil, Marathon...etc.

Pro Stock John

iTrader: (34)

Great info guys, I was wondering if winter gas can adversely affect dyno #'s but the answers sounds like it will not...

Patman

Gas weighs closer to 6.2 lbs per gallon actually, although it does vary slightly based on ambient temperature.