In our industry, there are hundreds of manufacturers for the automotive spark plug, with dozens available for a single application. There are standard copper spark plugs (for some older applications), platinum plugs and iridium spark plugs, and performance orientated plugs, with special electrode configurations and features designed specifically to help an engine consume fuel properly and increase fuel economy.
With so many brands available and specifications for each model being different, finding the plug that works best for your application depends in part on your ignition system configuration. For example, on the wasted spark ignition system, like the one found on the first generation Volvo S40 1.9T, each cylinder pair shares a common ignition coil. Cylinders that are opposite one another in the engine's firing order would share a coil, where only the plug that fires during the compression stroke would produce power. Because of this, both spark plugs experience about twice as much electrode wear as other more common ignition control types (as they fire every engine revolution rather than every other engine revolution). In this particular set up, it is more common to find longer lasting platinum spark plugs or iridium plugs because standard plugs will not last as long as the manufacturer would like or expect.
With coil-on-plug ignition systems, each spark plug has its own separate coil mounted on top of the plug. The types of plug used in these applications are typically not as important as this system fires with the same frequency as those on an engine with a standard distributor.
As for brand, most spark plug suppliers today offer a wide range of standard, platinum and iridium plugs for most makes and models of vehicles, not just the ones they supply as original equipment.
Now, typically the brand of plug used on most applications does not really matter, as most cross reference part numbers for each application usually follow the same guidelines and heat ranges. However, I've found that with many Volvo applications individuals prefer Genuine Volvo spark plugs as opposed to more common manufacturers like Bosch and NGK.
In doing some research I found the site below. It's a great help in breaking down spark plug specifications and I use it often to determine the differences between certain brands. In fact, I helped a customer just last week determine what the differences between Bosch FGR7DQP+ and FGR8DQP+ were for his BMW.
http://www.sparkplugs.com/product.aspx?zpid=8068
http://www.sparkplugs.com/product.aspx?zpid=8069
So it begs the question, what can our community can say about the kind of plugs to use and why?
About The Author: Mike Rivera
Mike Rivera is an ASE Certified Technician and Senior Sales Account Executive at FCP Euro. He can be reached at mike@fcpeuro.com
