Are we paying more for poorer quality gas ?

[slowrev]

I have noticed that all 93 octane gas is not the same. I can fill up my subie with 93 at one brand station and it rattles, 93 at another station and it really zooms.....
For the experts... my tractor manual says use 93 octane (Research method), how does that equate to the ROZ/RON method now used ?

 

[kcarl]

You may be getting 89 octane at one station and 93 at the other, though you are suppose to get 93 at both. There is no guarantee the right stuff is put in the tank.

 

[SkyPup]

What altitude are you operating at?

You'd only need the higher octane <1,000 feet above sealevel.

For each 1000 feet of altitude the atmospheric pressure will drop by a little less than 1 inHg thereby decreasing compression and allowing your engine, at altitude, to operate better on lower octane fuel. The higher you go, the less octane you need.

 

[MadReferee]

In many (a lot) parts of the country most gasoline comes from the same storage tanks at the terminal. In the greater Boston area it does for everything except Mobil. The only difference between brands is an additive package that is added at the rack when the tanker is loaded.

When I had my Citgo station my fuel was tested by an independent company hired by Citgo Corporate every 6 months or so. This was to make sure that I was selling true Citgo instead of fuel that did not have the Citgo additive package. The reason being is that the difference in price at the terminal was almost 10 cents per gallon between branded and unbranded.

Most of the stations that are not name brands sell unbranded gas that contains only whatever additives the refiner put into the gas. That's why they are cheaper than Citgo, Sunoco, or Shell.

Also, at least here in the Boston area, you can only get 2 types of fuel at the terminal, 87 octane and 93 octane. The mid-levels of pump gas are blended right at the pump. The difference you see in the types of 93 octane gas could well be in the additive package (or lack there of) that is being used by that particular brand.

Furthermore, your fuel may contain up to 10% ethanol or some other enhancer, especially in the summer months.

Confused? I hope not.

 

[slowrev]

What altitude are you operating at?

You'd only need the higher octane <1,000 feet above sealevel.

For each 1000 feet of altitude the atmospheric pressure will drop by a little less than 1 inHg thereby decreasing compression and allowing your engine, at altitude, to operate better on lower octane fuel. The higher you go, the less octane you need.

I am at around 300-400 ft.
My subie gets better mileage, more power, etc with 93, it always has. It is tuned per specs and still meets new engine compression specs.
I get at least 80 more miles per tankful of 93 vs 89 and no knocks. Repeated testing over 10 yrs has proven this.
And the owners manual states 93 gas is recommended for my IH2444 gasser.
Ben

 

[slowrev]

Mad,
Neither of the pumps says anything about Ethanol. My subie runs poorly on the ethanol stuff when I tried it.
The subie is fuel injected (throttle body).
I notice a real difference in power when using good 93 vs poor 91 or 93.
With 1.8 litres every bit helps

 

[SkyPup]

I've been running leaded VP Racing Fuel MS 98 without ethanol in all my high compression motorcycles and race karts, it works outstanding at sea level:

Specification Sheet: MS 98L

Specific Gravity: .715 @ 60°F

Lead: Leaded

Color: Light Blue

Motor Octane: 96

R+M/2: 98

RVP: 6.7

Oxidation Stability (min.) 1440+

Oxygen Content: 0%

Distillation:
10% evap @ 161.1°F
50% evap @ 206.7°F
90% evap @ 230.7°F
E.P. @ 298.4°F

Production: Elmendorf, Texas USA

Availability: Sealed Drums

For an explanation on the difference between Motor, Research and R+M/2 Octane Numbers, click here:

http://www.vpracingfuels.com/vp_10_techdata.html#


BTW, European Gasoline Octane levels are 4-5 points higher than anything available through retail in the US.

 

[slowrev]

You can still get the leaded racing gas ? the last time I saw that was down in NC 10 yrs ago.
Ben

 

[SkyPup]

You can still get the leaded racing gas for use only on race tracks, but with using unleaded the expensive iridium spark plugs last forever with virtually no deposits.

Even NASCAR is going to unleaded with 10% Ethanol though.....

 

[SkyPup]

Section 1. PRODUCT IDENTIFICATION: Leaded Racing Fuel

Leaded racing fuel is a complex mixture of petroleum hydrocarbons. This product is sold for non-highway use in racing motor vehicles only. The Leaded Racing Fuels do not meet the ASTM D4814 Specs for Motor Gasoline and do not contain deposit control additives required by EPA for street or highway purposes. Purchaser is responsible for notifying VP Racing Fuels in writing at the time of the purchase if the fuels will be used for purposes other than as a motor fuel in racing motor vehicles in sanctioned racing events. Purchaser may be subject to additional excise taxes and possible civil penalties for failure to comply with the requirements for using the leaded racing fuels “off road”.

Chemical Name(s) of Primary Component(s) CAS Number(s)

Petroleum Distillates Mixture
Lead 7439-92-1

Section 2. INGREDIENTS/SUMMARY OF HAZARDS
OSHA Hazardous (H)/
Ingredient(s) CAS Number(s) Non-Hazardous (NH) Percent
Benzene 71-43-2 H <10%
Toluene 108-88-3 H <10%
Dimethylbenzene (xylene) 1330-20-7 H <10%
Ethylbenzene 100-41-4 H <10%
Styrene (ethenyl benzene) 100-42-5 H <10%
1,3-Butadiene 106-99-0 H <5%
Isoprene 78-79-5 H <10%
N-Hexane 110-54-3 H <2%
Pentane/pentadiene 109-66-0 H <10%
Cyclopentadiene 542-92-7 H <10%
Lead 7439-92-1 H <10%


EXPOSURE LIMITS: No exposure limits have been set for this product, but exposure limits have been established for certain components of this product which are:

Chemical Name(s) ACGIH/OSHA
Benzene 0.5 ppm ACGIH TWA
2.5 ppm ACGIH STEL
1.0 ppm OSHA PEL
5.0 ppm OSHA Ceiling
Toluene 50 ppm ACGIH TWA
200 ppm OSHA PEL
300 ppm OSHA Ceiling
Xylene 100 ppm ACGIH TWA
150 ppm ACGIH STEL
100 ppm OSHA PEL
Ethyl benzene 100 ppm ACGIH TWA
125 ppm ACGIH STEL