Which Octane Fuel in 3.5 V6 Explorer ?

[MikB]

Pinging or detonation = marbles in a can.

 

[Flatplane]

marbles in a can by themselves are not noisey

Knocking (also knock, detonation, spark knock, pinging or pinking) in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder does not start off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.

The fuel-air charge is meant to be ignited by the spark plug only, and at a precise point in the piston's stroke. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive.

Knocking should not be confused with pre-ignition – they are two separate events. However, pre-ignition is usually followed by knocking.

The phenomenon of detonation was first observed and described by Harry Ricardo during experiments carried out between 1916 and 1919 to discover the reason for failures inaircraft engines.[1]

 

[MikB]

In my experience, telling the layman that pinging or detonation sounds like marbles in a can usually get's the point across. However, if they are interested in knowing more, they can do like you did and google it.

 

[peterk9]

How do you know your engine is pinging? I use 87 and my engine's performance seems to change off between powerful and weak sometimes.

If these new engines are the same as the older ones then you should be able to hear it unless the sounds is muffled by the insulation. I never had pinging with the 2011 nor with my current vehicle using 87. I always buy my gas from the same station or same name brand.

Peter

 

[Flatplane]

These new engines are better than the older ones. The insulation does muffle the noises better. Variable valve timing and increased compression ratio will help mileage and performance. Direct injection also maximizes the volumetric efficiency to enhance all aspects of performance. One of the plus sides that fuel manufacturers enjoy is the better fuel mixtures mean the quality ie. volatility of the fuel does not have to be as pure as it used to be for the older engines. The quality of the fuel we are able to buy these days would not be acceptable with "back in the day" engines. In order to achieve the fuel quality today fuel manufacturers add a package to the fuel to get to the same level we used to be.
Just Sayin!

 

[1995E]

These new engines are better than the older ones. The insulation does muffle the noises better. Variable valve timing and increased compression ratio will help mileage and performance. Direct injection also maximizes the volumetric efficiency to enhance all aspects of performance. One of the plus sides that fuel manufacturers enjoy is the better fuel mixtures mean the quality ie. volatility of the fuel does not have to be as pure as it used to be for the older engines. The quality of the fuel we are able to buy these days would not be acceptable with "back in the day" engines. In order to achieve the fuel quality today fuel manufacturers add a package to the fuel to get to the same level we used to be.
Just Sayin!

Yeah... I wish I could buy non-ethanol gas... Sucks that I can't find a station that has non-ethanol gas.

 

[peterk9]

How do you know your engine is pinging? I use 87 and my engine's performance seems to change off between powerful and weak sometimes.

Have you checked out this site? Just going by a quick glance it seems that the non ethanol gas is 91 or higher.
http://pure-gas.org/

Peter

 

[Flatplane]

ethanol is an oxygenating additive that diffuses the tailpipe emissions to an EPA acceptable level.Yes it is sad the total power development is less and the caustic effects on the fuel system components is detrimental to longevity but federally mandated restrictions are met at consumer level suffering.