Spark plugs may appear similar, but in reality, they are significantly different in efficiency. Besides just starting combustion, different spark plug materials and sizes will affect how well they perform in your particular vehicle. What was the best spark plug for one vehicle could be the poor choice for another vehicle.
The days of just copper are over because iridium, platinum, and double platinum last longer and require less voltage from the ignition coil/flame thrower to start combustion.
We will compare every modern-day spark plug type to make it easier for you to decide when it comes time to replace your spark plugs.
Types of Spark Plug
Spark plugs come in different materials. However, generally only the center electrode (the common part) of the spark plug is made primarily of that material. For example, a double platinum plug has a platinum center electrode and a side electrode.
Now let’s look at each type of spark plug in detail.
#1. Copper Spark Plugs.
Copper spark plugs are the most popular and the most commonly used on the road today. The inside of the plug is made of solid copper, while the center electrode is a composite nickel alloy with a larger diameter than the other plugs.
This means it has more voltage requirements to make an electric current. Nickel is a relatively soft material and does not last long, so it is not appropriate for spark plugs on modern vehicles.
If you drive an older vehicle (1980s or earlier) that has low electrical values, copper spark plugs would be perfect.
Pros
- High electrical conductivity helps produce a better spark
- Cheap and readily available
Cons
- Moderately short lifespan (20-30K) compared to others
- Not made for the latest applications for modern high-performance engines
#2. Iridium Spark Plugs.
Iridium spark plugs outlast any other type of spark plug. This means more performance in your car, especially if you have a performance-tuned vehicle. The reason is that iridium is a metal even tougher than platinum. And while iridium spark plugs cost more, they will save you money in the long run.
Iridium spark plugs have one feature that is significant. Their center electrode is small and very dense, allowing it to reasonably create the electric current needed for combustion inside the cylinder with less voltage. These center electrodes are a reason why iridium spark plugs are used by car manufacturers.
But be careful!!! If you have iridium spark plugs, it is important to not replace them with platinum or copper spark plugs when you need to replace them. You will lose performance in your car.
Pros
- Lasts longer, 80,000 – 100,000 miles
- Better performance because of longevity, better for performance-tuned engines
Cons
- More expensive than copper spark plugs
- Harder to find at some places that sell automotive parts
#3. Platinum Spark Plugs.
Platinum spark plugs look similar to copper spark plugs but the difference is a platinum disc welded to the tip of the center electrode that improves durability and longevity up to around 60,000 miles.
Platinum spark plugs are not only durable, but they also burn hotter than copper spark plugs, which helps to reduce deposits that can cause fouling. Less maintenance for you, more time on the road.
If you drive a new car with an electronic distributor ignition system, platinum spark plugs are recommended. They last longer, perform better, and you get a better return on investment. Good choice for any car owner.
Pros
- Last longer than copper, 60,000 – 70,000 miles
- Perform better than copper plugs for modern combustion chambers/ engines.
Cons
- Costs more than copper plugs
- Some high-performance engines still prefer iridium over platinum.
#4. Double Platinum Spark Plugs.
If you’re operating a car that uses a waste spark system on its distributor ignition, then double platinum spark plugs are usually a safe bet.
Since this waste spark system fires the spark plugs twice on each cycle (when the engine is serving a compression and exhaust stroke), this may seem wasteful, but it really helps for reliability within the system.
Additionally, with a waste spark system, it can fire spark plugs in rain and is not affected by different environmental rigors such as dampness.
This allows the driver peace of mind. Many owners love to know that they don’t have to compromise or worry about whether or not they can get to their destination, despite conditions.
Pros
- Greater longevity vs. single platinum, approximately 70,000-90,000 miles
- More performance with newer engine designs
Cons
- Typically, more costly than single platinum spark plugs
- But, may not achieve transformational improvement over iridium plugs.
#5. Silver Spark Plugs.
These spark plugs have silver-tipped electrodes. Silver has great thermal conduction and is often used in motorcycles, race cars, and older performance European cars.
These spark plugs are good, but will deteriorate sooner than platinum or iridium-tipped spark plugs, so they will need to be replaced sooner.
These plugs don’t generate as much heat in the combustion chamber to cause failure and can potentially prevent engine damage, In turn, they may not be the best plugs for the job when you require a stock long-lasting plug.
Pros
- Heat transfer forms can be optimal for engine performance.
- Excellent conductivity allows for precise ignition.
Cons
- Have a shorter life than platinum and iridium.
- Not as common and may be difficult to find.
Things to Consider Before Buying
Vehicle Requirements
Always check your owner’s manual for the specific type of spark plug required for your vehicle when selecting a new plug.
Different vehicles call for different specifications, so just because one of your vehicles performs well with a particular type of spark plug doesn’t mean your other vehicle will have the same response.
Depending on your vehicle’s make and model, there may be recommendations for copper, platinum or iridium spark plugs.
Numerous automotive forums that cater to your vehicle’s make or model are also worthwhile resources when finding out what vehicle enthusiasts’ recommendations are.
Engine Performance
Your engine performance can be affected based on the type of spark plug you select. While copper spark plugs have the ability to provide the best conductivity, platinum and iridium have better resistance to heat.
Keep in mind that the center electrode also affects how the heat is distributed while also affecting the spark plug’s performance.
Longevity and Replacement
Another important aspect to consider when deciding on your next spark plug is longevity. While copper spark plugs provide excellent engine performance, they will not last nearly as long as platinum or iridium spark plugs.
You can expect copper spark plugs to be around 30,000 miles, while platinum and iridium spark plugs can be expected to last approximately 100,000 miles. However, these are not thumb rule types of numbers. The best advice is to check the condition of your spark plugs periodically.
Cost
It seems relatively inexpensive to be purchasing spark plugs; however, just because you’re buying a single spark plug doesn’t mean you will only need a single spark plug installed into the engine.
In most cases, you will need somewhere in the neighborhood of 4 to 8 spark plugs. In total, expect to pay anywhere from $20-$80 to replace your vehicle’s spark plugs.
Spark Plug Benefits and Trade-Offs
High-Performance vs. Standard Vehicles
Using the right kind of spark plug is essential to getting the best performance out of your performance vehicles and motorcycles. Iridium or platinum plugs can provide better conductivity and a longer life than copper plugs.
But, in standard commuter vehicles, copper plugs can work and are cheaper. Again, do check your owner’s manual for the kind of spark plug suggested by your manufacturer.
Fuel Efficiency
If you’re trying to be fuel efficient with your vehicle and you are looking at spark plugs, keep in mind that the choices you make can affect the amount of fuel your vehicle uses.
Iridium and platinum plugs will offer better fuel efficiency because they can maintain a spark longer, resulting in better combustion during the compression stroke of the internal combustion engine.
Copper plugs typically wear out faster and will not offer the same amount of use as iridium plugs or platinum plugs.
Emissions
The spark plugs you choose can also affect emissions. If a spark plug can better facilitate a more efficient combustion process, it will probably lead to lower emissions. Again, iridium or platinum plugs are known for having a more consistent spark, not only better fuel efficiency but also less emissions in your vehicle.
Additionally, if your vehicle is using some kind of wasted spark ignition system, then double platinum plugs would be preferred because they endure better than most specialty plugs with inner construction. Copper plugs won’t be as effective, given their cheaper price and time limitations for spark duration and total lifespan.