Kinda goes like this... high compression high octane - high heat high octane. Higher octane fuel burns slower and is less prone to explosive detonation. If you "get away with" running anything lower than 91 octane then you're just getting away with it. If it's pinging (sounds like ticktickticktick when throttle applied) then you're not getting away with it. A little pinging "now and then" is pretty common, but not continuous. Detonation, as previously mentioned, is an immediatemotor slayer and is typically caused by serious mis-timed engines or carbon build-up in cylinders (NEVER happens to a properly ridden muddersickle). The other "typical" source of detonation is plugs that are too long and have a thread or two in the combustion chamber providing enough heat to ignite the A/F mixture (out of sequence)... Not a problem unless you're using some off the wall plugs.

Don't have the reference at my fingertips, but there are a few articles floating around on the net that also pretty much poke holes in most octane booster claims made by their manufacturers/marketing types. That being said I carry a few packets of POCKET FUEL along whenheading out of town - I've hit a few stations out in the sticks that only had 89 or 87 octane and the POCKET FUELdoes make "enough" of a difference to minimize the worst of the pinging.

And yeah, it irritates me a little when my YamaHonda buddies fill up their water-cooled sleds with $3.09 a gallon 87 octane fuel and I gotta go across the street and get the $3.59 a gallon stuff.

 

Overall a typical gasoline is predominantly a mixture of paraffins (alkanes), naphthenes (cycloalkanes), aromatics and olefins (alkenes). The exact ratios can depend on

1. the oil refinery that makes the gasoline, as not all refineries have the same set of processing units.
2. the crude oil used by the refinery on a particular day.
3. the grade of gasoline, in particular the octane rating.

Most refiners use one or more of these to increase octane:

MMT
MTBE,
Ethanol
ETBE
Benzene
Toluene
Naphthalene
Trimethylbenzene



A good rule of thumb in purchasing an Octane booster is to purchase as fresh a date as possible, it must be in a metal container and have either MMT, alcohols, or aromatics as its active ingredient... The drawback to any of these additive ingredients is the diminishing effect they have on higher-octane fuels. Adding the same booster to 87-octane pump gas will yield a lot more octane gain than adding a bottle to 91-octane premium gas.

Here are a couple of brands that have been tested and passed and can be truly called octane booster... many others out there are a waste of money!

1. (NOS) Racing Formula octane booster
2. Outlaw's Super Concentrated Octane Booster