Octane sounds like a product that could turn regular fuel into something that could launch a rocket.  Oh contraire, octane makes fuel burn slower not faster.  By burning slower, octane resists predetonation, the pinging sound that crap cars make.  The predetonation is a result of the fuel/ air mixture igniting before the piston has reached the top of its stroke.  Hence, the rattling noise that indicates the engine is in trouble.  Left unchecked, this condition can burn a hole in the top of the piston.

Your stock Porsche has sensors capable of listening for knock.  Should they detect any knock, they will retard the timing to eliminate the knock.  Modifying your engine management system with a chip may interfere with this process. Should you use an inferior product, you may notice a drop in performance; but your Porsche's engine will protect itself from predetonation.

In most cases, 93 octane should be sufficient.  Only some heavily modified Porsche's should require a higher octane rating.

Your fuel warning light will come on with a reserve of approximately 2 ½ gallons.  Should you be caught out in the boonies with no high octane fuels available, you can put in enough fuel to get you to a station where you can purchase premium fuel.  Your knock sensors will protect you.

Know your fuel capacity and have an idea as to what kind of economy you may expect.  On the interstate we will be stopping for comfort before the necessity for fuel.

Four of the largest automobile manufacturers have identified what they consider "Top Tier" gasoline.  This is based upon the detergents in the fuel that prevent deposits from sticking to the valves and injectors, creating inefficiencies in the combustion process.  By recognizing companies that comply with these higher standards, consumers can make better choices when purchasing fuel.

You may be surprised with the results.  I know I was.  There was at least one glaring omission.  The names that you will recognize on the list are:  Chevron (no surprise there), Conoco, Phillips, Shell, and Union 76.  I was expecting Exxon.   

The "Top Tier" list said they would include other fuels as they met the requisites.

Car and Driver  magazine brought this to my attention years ago.  They pointed out that using the proper fuels and possibly spending a little more far out weighed the consequences of not using gasoline with the correct additives.

One of my biggest concerns in years gone by on the Ozark tour was getting sufficient octane north of I-40.  It used to be almost impossible.  Exxon stations were the first to give us 93 octane north of I-40 in Arkansas.  Based on this new information, I have added the Conoco stations in Eureka Springs and Berryville.

You may want to take note of any "Top Tier" sightings and share that information with the group.

"Fill'er up," just got a little more involved and interesting.

At the conclusion of this article, you guessed it; I called Exxon to see why they weren't on the list.  They read an e-mail to me that stated, in fact, they do qualify for the "Top Tier" list.  I'm awaiting more documentation from them, but I'm pleased to know that I haven't been endorsing their product in vain.

I have now received both a copy of Exxon- Mobil's e-mail stating their position and a phone call from a very high official of the company.  The explanation of Exxon's decision to choose not to participate in the "Top Tier" program was excellent.  For both political and ethical reasons Exxon has chosen not to certify through this group.  This is, by no means, a copout.  It made perfect sense to me.  Top tier was developed for the manufacturers to skirt warranty issues.

While speaking to them, I also verified that Mobil and Exxon fuels are the same.  That's good to know in Illinois where you only have Mobil.  My endorsement for their products remains unchanged; they are great for your Porsche.  BP sells Amoco Ultimate which also seems to do a very nice job.  Finally, FYI, Chevron and Texaco sell the same fuel with Techron which is my favorite additive.        

Read more from the "Just Jack" article base

 Braking  Breaking in your new Porsche
 Dealing with the
 Driving Position
 Gasoline  Literal Translation
 Oil type and Weight
 Performance Driving 101
 Road Rash
 Radar Basics
 Tires  What separates you from impending doom
 Your worst nightmare has just come true
 Red Mist
 Fatigue Got to go right now!
 Dynamic Cornering Lights
 Literal Translation


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