Which spark plug do you use in your Mazda? If you've tried plugs other than the OEM plugs, what were they and how well did they perform in various driving conditions (city, highway, flat, mountains, extreme heat and cold etc.)? What about durability? How about mileage? Please include the model and year of the vehicle, as well as the mileage. Thanks.[align=left] [/align]

 

I just installed a set of Bosch Platinum Ir Fusion plugs in my 2003 Protege DX with 30,000 miles. OEM were NGKs. Thus far the Bosch are working very well. Car performs very well. These plugs have a fairly radical design compared to traditional plugs.
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Generally with imports it's the best to stick with either NGK's or Bosch plugs. I'm curious as to how the Bosch ones you put in perform compared to the stock ones, I'm a little skeptical about those plugs with the 4 contacts. It seems to me like a bit of a gimmick, you still have the same amount of current running to the plug, so with those plugs you have four, weak sparks, whereas with the standard ones you have a single, strong spark, which seems to me like it would work alot better. I guess you won't notice much if you're not running boost or higher compression, but I'm just curious.

 

First, the Bosch plugs are performing very well. The car runs great. I can't tell whether they are performing any better than the OEM NGKs. The car starts easier and seems to idle more smoothly than it did with the old NGKs installed, but those plugs were old (30,000 miles) and the Bosch are brand new, so I really can't say.

The four side (ground) electrodes are no gimmick. Since current takes the path of least resistance and it isn't possible for the 4 electrodes to each provide the exact same resistance, only one of the four electrodes is used each time the plug fires. However, over the life of the plug, this will not always be the same electrode, so you spread the wear between 4 electrodes, rather than using a single electrode for the life of the plug. This helps extend the period of like new performance and increases the service life of the plug. Another advantage to the Bosch design is the fact that the spark is not shielded from the air/fuel mixture as it is with a conventional design.[align=left] [/align]

 

Hmm, good point. So you're saying that the spark will use a single electrode until it becomes fowled then will switch to another one? Ya, I guess the advantage then would be the mileage you get out of the plugs. How much are they compared to the oe ngk's?

 

The OEM plug for my vehicle is the NGK BKR5E11. I believe they sell for about $4 each. The Bosch Fusion plugs sell for $10 each.

You mentioned that if the ground electrode in use is fouled, then one of the other 3 would then be used. Although this is true, it isn't necessary for the electrode in use to become fouled for the spark to start jumping between one of the other ground electrodes and the center electrode. The slightest increase in resistance is all that is needed for the spark to start jumping between the center electrode and one of the other ground electrodes.[align=left] [/align]

 

Nifty.