A good article. I have resorted to using high test or higher octane gas in my small engines. The biofuels added to lower octane gas may assist in lowering engine knock but in small engines, particularly those that are used seasonally, the biofuels tend to gum up the the fuel systems and create havoc in engine starting. When it snows, I want my snow blower to start. Nothing like having to spend the morning tearing apart your engine.

"For most modern, computer-controlled cars on the road today, this perception is more mental than it is factual."

Ummmm . . . . for cars that have knock-sensor enabled ignition timing, this is FACT. My lowly 2005 VW Jetta with the 2.Slo engine returned an extra 2 (~ 6%) miles per gallon on a highway trip I've made many times at identical speeds (cruise control) in similar weather conditions when I tried a tank of 93 octane. (It by no means makes up for the increased cost but I tried it for 'its and grins because engineering minds have to know.)

Most cars with knock-sensor ignitions will advance the timing up to the point of detonation then dither the advance about that point.

The article was good, but it surprised me that no mention was made of what actually happens when an engine "knocks" and the fault is not corrected.........everything else appeared to have been mentioned!!!!

I know from (a bad) experience many, many years ago.......cost a new engine in "lucky for me" a company car!!! No my wallet!!!

The actual problem was down to a Ford service mechanic that stripped out the screws when setting up the points. This caused the engine to slowly over several hours driving to "advance". The result was a blown engine.

When I picked up the repaired car, I asked if the distributor was the one from the old engine, "yes" was the answer. I then asked if the base plate had been replaced or repaired which elicited a "Why?" I told the manager that was the original reason for the engine malfunction. He did not believe me but looked, found the problem immediately and took one off a brand new showroom car to get me back on the road again (Willie Nelson!!).....

Note that I haven't mentioned it exactly either.......but many here should know, let us wait and see......

Nobody seems to know what actually happens in an older motor with "Pinking".

Basically two things, 1) the bearings on the big and small end may be damaged due to the "Explosions" instead of "Burning" of petrol/Gas. This is not a given.

Also, 2) the engine will overheat, albeit usually slowly heating up......

I hate to think how much money my wife wasted on premium fuel for her Lexus RX-330 on the advice of the local Lexus dealer. I knew it was crap, but she chose to listen him, not me. After about a year she decided that "ordinary" was OK, and sure enough the mpg stayed the same.

Question: Can we even hear "pinging" or "pinking" on a luxury modern car - even if it's occurring?

On a modern car there is a "Knock" sensor that "hears" the knock before any human can and adjusts the timing to get rid of it.....you or I will never notice anything happening....

If you ever hear it on a modern engine, there is a serious problem....I suspect that the "Check Engine" light will have been on for a long, long time.....

!!