When working towards improving the fuel economy of our vehicles it is important to look at all maintenance items that can be replaced or improved. Spark plugs are one of these maintenance items that can improve fuel economy by replacing them, as well as improve fuel economy even further by upgrading them.

How do spark plugs work?

It is important to first know how spark plugs work, after fully understanding how spark plugs work in relation to the engine we can really see how they can in fact improve fuel economy in a measurable way.

When fuel is sucked or pushed into the cylinders of the engine fuel is added through fuel injectors. This creates an air / fuel mixture which is then burned. That burning fuel creates energy in the form of heat, which pushes the piston down and creating power.

The mixture of air and fuel is ignited by the spark plug. Modern engines while efficient, are not 100% efficient… not even close. In this case all of the air / fuel mixture is not burned completely. This means that there is untapped power and untapped fuel that could be used to keep the car moving. By using the fuel more efficiency our cars fuel economy increases.

What Spark Plugs Will Increase My Fuel Economy?

There are several aspects of a spark plug that can burn the air / fuel mixture more completely and improve fuel economy. The major factors are material, gaping, and the ground strap…

Material

The most common materials a spark plug is made out of would be copper or platinum. Platinum plugs have gotten a lot of press and marketing in the last decade or so. One of the major marketing messages is that platinum plugs increase fuel economy.

The truth is that copper actually conducts electricity better than platinum and produces a stronger spark (and thus a better burn). However copper doesn’t last as long as platinum, which is why platinum in the longer run can produce better fuel economy.

The moral of the story is that if you can replace the plugs more often stick with copper. They will produce better fuel economy and cost less than platinum plugs.

Gapping of Plugs

The gapping of plugs is the distance between the electrode of the plug and the strap. Every car has a specific gap that they are designed to run with in. This can be tweaked slightly to increase fuel economy.

A larger gap (or distance between the strap and the electrode) will produce a larger spark and allow more air/fuel mixture to be ignited. Where a smaller gap will produce a stronger and more intense spark.

In most cases the best way to find out what works best in your car is to test bethod methods.

Ground Strap

The ground strap design itself can make an impact on the burn of the air/fuel mixture. The most common method of ground strap is a simple bit of metal that the spark can travel between. However there are a few other methods that can improve performance in some machines. Bosch creates a spark plugs that have several ground straps (2 or 4 depending on price.) The idea is that it allows the spark a more direct access to the air / fuel mixture creating a more complete burn and increased fuel economy.

There is also a “split fire” design where the ground strap looks as if it would be a single design just split at the end. This is supposed to create a best of both worlds situation where the spark is strong but still has access to the air/fuel.

Putting it All Together

The best bet situation would be to buy a high quality copper spark plug and put the gap on the tighter side of the spectrum. If you are able to experiment try contrasting it with a platinum plug with 4 electrode design.