The pumps at the Sunoco stations used to let you dial your octane, many settings, 86 through 95.

This one has 8 settings!

http://tommcmahon.typepad.com/.a/6a0...3abe970b-800wi

Wow... Cool!

Did ya know that you can combine a 50/50 mix of 91 octane unleaded And 91 octane leaded and get >92 octane gas?

I heard an interesting statement at lunch today with a VP.
He said "25% of all cars on the road in So Cal are buring gas made in this refinery. 1 out of 4 ....."

For as long as I can remember the price between grades was 10 cents, so from regular to premium was 20 cents. As fuel passed $3 many years ago it was still 20 cents which I thought was strange since the price per gallon was 3 times more. I guess the gasoline companies finally realized the same thing because now in Houston it's 60 cents from regular to premium :(

That decision is made by the retailers.

http://foodnetworkhumor.com/wp-conte...h-say-what.jpg

A refinery does not calculate the cost of each product. It instead compares the total value of the product produced vs the cost of operations (including raw materials) and calculates a standard margin for all products. A refinery produces some byproducts that have little market value and the objective is to design a refiney that minimises the production of these low value products - i.e. invest in a reformer to upgrade low value products into high value blending components. The process to optimize a refinery is to run sophisticated models that simulate different economic conditions and different operating conditions to identify the conditions that maximize the profits.

The street price and the differentials between grades are a function of supply and demand in the local market.

Same here in MS. I live in a college town so everything is 30 cents a gallon more than any surrounding town. Last weekend I filled my wife's car up (in another town) with 93 for $2.89 a gallon. 89 was $2.29. E85 was listed across the street for $1.99. Been a long time since I've seen any fuel with a one in front. -J

Measuring octane is an interesting thing, actually there are a few different ways:

There is the RON which is the Research Octane Number and its determined by running fuel in a very specialized test engine (one cylinder I believe) - it is able to vary the compression ratio and measure the response for the fuels and compare it to isooctane (an octane of 100) and heptane (and octane of 0) values. These are the standards. The engines ain't cheap and even more costly to maintain. I know a man who travels the country servicing them and he pretty much writes his ticket!

Then there is the MON or Motor Octane Number. This is similar to the RON test but the fuel is heated, the engine RPMS are run higher and they do something with the timing as well all in an attempt to push the fuels anti-knock to the limit. There is no direct link to the RON number and the MON number but the MON can be as much as 10 points lower then the RON. The value we see at the pump is an average of RON and MON which is referred to as the AKI or Anti-knock Index or the PON or Posted Octane Number. Next time your at the pump you may see the equation (R+M)/2, thats what they are referring to.

Did you know methane has a RON and MON of 120? Methanol and ethanol have RONs of 108 but MONs of 89. Isopropanol and xylene have RONS of 118 as well but toluene has a RON of 121.

Those octane booster additives that you buy is nothing more then paint thinner or alcohol!

Tetraethyllead is an octane booster.

By law, Chicago has THEIR EXCLUSIVE additive and changed for the seasons. They jack the cost to everyone. The additive formula is another bs component with further taxes collected on it as well.

The additive component alone is big biz.

global fuel additives market to reach $7.8 billion by 2019

http://www.bizjournals.com/prnewswire/press_releases/2014/10/28/MN48387

Yea, but where do ya get the 91 octane leaded gas now days?

I remember back in the day when leaded gas was available some of my friends with high performance cars would do that. I was driving around in a VW bug back then so it did not matter to me.

As a side note related to price, we just returned from a trip through Arizona, NM, into west Texas from the SD area. I was happy to see prices as low as $2.56/gal. and mostly $2.65+ with some significantly higher in out of the way places. I was totally surprised when filling the tank of the rental car before returning it, that the price at Costco in our area was $2.43/gal. Never expected that in a million years.

Small airports. Cessnas and such still use it. You can also buy racing fuel with lead in it.

yes but aviation gas is usually 100LL, you would not be mixing that as it is already 100 Octane.

it is $2.49 here in VA. .20 more for midgrade and .40 more for premium

and .80 more for not adding corn here to regular 87


I did note lots of 85 octane rated gas out west but never see that here in Fla

occasional 86 and that is only at the new multi grade pumps in off brand stations
they have 6 grades 1 octane number apart and 10 cent a extra octane per gal

Ethanol boosts the octane very nicely...but it has its share of issues.

Two tanks under ground three grades at the pump.......