In engineery terms, fuel efficiency means the thermal capacity of converting the energy contained in the fuel to kinetic energy, or work, needed to move your car. For a vehicle, fuel efficiency means the output one gets for a unit amount of fuel input, such as "miles per gallon" or "litters per 100 kilometers". For you, fuel efficiency simply means less fuel wasted and more money in your pocket.
The automotive industry believed that by maintaining the air/fuel ratio of 14.7:1 by electronic means, like electronic fuel injection and electronic ignition systems, they had already achieved the best combustion process that assures the best fuel economy.
Unfortunately this is not always true because is not sufficiently known, but there are a lot of very ordinary daily driving situations that makes than the engine operates steady at low speeds, creating less temperature in the combustion chamber. It makes that the stock spark plugs results operating too cold, which affects the combustion process, because the low temperature do not allows to burn completely the air/fuel mixture in the combustion chamber.
Unburned fuel is wasted fuel and you paid for it. Wasted fuel is wasted money.
These very common driving or traffic conditions are:
&bullSteady city driving, where prolonged idling or short distances and stop-and-go driving prevails.
&bullExtended low speed driving, or short distance driving or even in the freeway driving where the automatic transmission maintains the engine under 3000 RPM.
&bullLow speed cruising.
&bullAt high elevations, above 3000 ft.
&bullWeather conditions, where the humidity rises.
&bullMoreover, these conditions may combine in endless ways.
And believe it or not, this situation is not the exception, in fact is almost the rule for more than the 75% of the cars worldwide. You can confirm it simply by seen the exits of the exhaust tips in any parking zone and in anywhere around you. Most of them are covered with dry black soot produced by the unburned fuel. And this is not due to an incorrect air/fuel mixture adjustment in the carburetor or the fuel injection system; even this occurs in a well maintained vehicle which just passed the smog test satisfactorily.
This is because the stock spark plugs are being too cold for those operating conditions, consequently are no longer adequate and must be substituted by spark plugs with a different and hotter heat range.
Why occurs it? because the heat range of the original stock spark plug was defined by the manufacturers at their laboratories, based on differents and teorical speeds, and trips, that supposedly should be done by the potential target market who conceptually will buy a gived model and type of vehicle. But in the real life, not all the people have the same driving habits nor lives in the same geographical and under the same weather conditions, or drives in the same traffic conditions neither gives the same maintenance to their vehicles.
Do you still have doubts? Think just a minute that the traffic between a big city like LA is very different from a smaller city and from a town. A teenager drives different from his mother and she drives different to her husband, whom drives different to his neighbour whom tows a trailer. Additionally from Alaska to Dubai, there are hundreds of different weathers, altitudes, and humidities; and there are many different fuel brands and qualities, among other different conditions.
So it is absolutely necessary to refining and tailoring the selection of the spark plugs for matching the real operating conditions of the engine to each individual driving habits and or each particular operating conditions.
As you can see, it is more likely that you are having Heat Range problems that are affecting your mileage, even if you didn't know they existed, and you are wasting more in fuel than neccesary.
To achieve the best fuel economy in these extremely frequent but seldom considered driving conditions, you must install different and hotter spark plugs than the original stock, suggested by the manufacturers in their application catalogs in order to achieve the right combustion chamber temperature that ensures the perfect combustion process.
But to define which exactly is the sparkplug, whose heat range results being the best adequate for your engine, is a risky puzzle and not an easy task.
Nevertheless, only by tailoring the selection of the park plug's heat range, customizing it to your particular conditions, you will achieve your engine's top efficiency, thus guaranteeing the best fuel economy, whit the best performance, power, reliability and low emissions.
Hard to believe?
You don?t have to take my words. Spark plug manufacturers have never failed to explicitly acknowledge that:
"A hotter spark plug may be better for prolonged idling or city type stop and go traffic".
AC DELCO Spark Plugs
"A hotter plug is better for prolonged idling and city travel".
BOSCH Spark Plugs
"Use spark plugs with a hotter heat range for steady city driving".
SPLITFIRE Spark Plugs
"For short distances and stop-and-go driving a hotter plug is better".
DENSO Spark Plugs
"The spark plug heat range should remain the same unless also at high elevations, (above 3000 ft ), in which changing to a hotter plug may be necessary".
CHAMPION Spark Plugs.
"This is reflected in the increased importance assigned to precisely adapting the spark plug to engine. Customized solutions are the order of the day".
BOSCH Sparkplugs
