We are reader supported. If you buy through the links on our website, we may earn a small commission at no additional cost to you. Our endorsements are strongly based on our intensive research online and we do not accept payments or gifts in return. Learn more.
A spark plug may be one of the cheapest components of a car engine, but it is one of the most important parts which determines the overall performance of the car, including fuel efficiency, horsepower, and acceleration.
If you have been experiencing power loss and poor fuel economy lately, it might be the signs of a bad spark plug, and replacement would be necessary. Cleaning the spark plug electrodes may improve the conditions, but it is better to change them if they are more than two years old. Carbon deposits and dust tend to accumulate at the electrodes over time.
Choosing one of the best spark plugs, preferably an iridium spark plug, can increase the horsepower as well as the mileage. We, just like all other mechanics, recommend iridium since they are long-lasting and provide better sparks than the nickel-alloy spark plugs. Platinum spark plugs too are also good, but not as good as iridium ones.
Table of Contents
- Iridium vs Platinum vs Copper Spark Plugs: Which is better?
- The 5 best spark plugs for horsepower & efficiency
- Frequently Asked Questions
- Some more high performance spark plugs
Iridium vs Platinum vs Copper Spark Plugs: Which is better?
Combustion: Take a note of the idle RPM when Copper, Platinum, and Iridium spark plugs are connected. You’ll see that the RPM is the best when Iridium is connected, and Platinum comes second. Since the fuel inflow isn’t altered. you’ll also notice an increase in fuel economy when you use an Iridium spark plug. However, Iridium and Platinum spark plugs are slightly more expensive than Copper spark plugs.
Conductivity: Iridium spark plugs conduct electricity and heat better than Platinum or Copper spark plugs. The melting point of Iridium is 4471°F, while that of Platinum is 3215°F. This results in Iridium spark plugs outperforming Platinum spark plugs, especially on longer drives.
Longevity: Iridium spark plugs are changed every 80K-100K miles, whereas Platinum spark plugs are changed every 60K miles. Copper spark plugs? Just 20K miles!
Now you know why Iridium spark plugs are the best, but at the same time, they are more expensive than Platinum or Copper spark plugs. All of it comes down to whether you want superior performance, fuel efficiency, longevity, or average performance at a lower cost.
We have reviewed some of the best spark plugs on the market. This includes iridium, platinum, and nickel-alloy spark plugs. You may choose the best one according to your budget and preferences. You can buy them online or go to a nearby shop to get them.
The 5 best spark plugs for horsepower & efficiency
1. Best Spark Plug for Horsepower: NGK LKAR7BIX-11S Spark Plug
This spark plug is capable of improving your vehicle’s performance by a good margin, thanks to the enhanced ignition and 0.6 mm laser welded iridium tip. Also, it comes with all the features needed to prevent any issues related to spark plugs, like a longer insulator nose to prevent fouling, corrugated ribs to prevent flashover, and it comes pre-gapped to 0.044″ by NGK, at which it is found to perform at its best, though you may need to adjust it to manufacturer’s recommended gap.
The most important thing that we should mention is the performance boost. Using this spark plug, you can expect a good increase in horsepower even if you were using Iridium spark plugs before, because this one is made to give you the satisfaction of superior performance, and that is exactly why it is in our list of the best spark plugs.
While it may not give an increase in fuel efficiency if your vehicle is in good condition, it will give you a good balance between efficiency and power. This spark plug is on the market only since 2018, which means that it comes with the latest technologies and improvements in this field. It is also one of the top racing spark plugs.
- Best spark plug for performance.
- Corrugated ribs.
- Longer insulator nose.
2. The Best Long Life Spark Plug: Bosch 6747
Platinum spark plugs may not be as good as iridium spark plugs, but they are far better than copper spark plugs in terms of service life and performance. This one, in particular, lasts three times longer than copper spark plugs due to its platinum firing pin and yttrium enhanced ground electrode as claimed by the manufacturer.
It may be one of the most expensive spark plugs, but the quality craftsmanship associated with the brand and its longer life justifies it pretty well. Bosch is one of the most trusted brands for electrical goods including spark plugs, and we keep the expectations high when the product is from them.
Coming to the features, Bosch guarantees four-year performance satisfaction which makes us feel free when buying this platinum spark plug. It is one of the best platinum spark plugs for horsepower as well, we should expect it to go a long way forward than others.
It comes with a 360-degree continuous laser welding to fuse the platinum firing pin, and the fine wire design assures good ignitability and performance. If you prefer platinum spark plugs, this one is a great option.
- 3 times longer service life than copper spark plugs.
- Fine wire design.
- Four-year performance satisfaction guaranteed.
3. Best spark plug for fuel economy: NGK Laser Iridium ILFR5T11
What makes a spark plug the best?
Different people might give different answers – a performance enthusiast might not care about the fuel economy and a daily commuter might give up on performance for fuel economy.
But the NGK Laser Iridium Spark Plug ILFR5T11, the best budget spark plug on the market, gives an optimum balance between fuel economy and performance. Being an Iridium spark plug and being from one of the best brands, the NGK, this spark plug is designed to last longer than the traditional spark plugs.
It is one of the latest spark plugs from the brand, and hence it is the latest technology product. The center electrode is made of iridium which reduces voltage requirements to fire the spark plug, and the ground electrode is made of platinum. This dual precious metal design is proven to give supreme ignition and longevity.
It comes in a pack of 4, so you can change all of your spark plugs for a sudden spike in performance or change only the necessary ones and save the rest for later. It is expected to last more than 80,000 km on average.
- Lasts around 80,000 km, longer than Platinum and Copper spark plugs.
- One of the best spark plugs for performance
- Dual precious metal design.
4. Best yet cheap NGK Spark Plug: LKR7DIX-11S Spark Plug (93175 Iridium Ix)
If you are looking for a cheaper alternative, go for the NGK LKR7DIX-11S. It costs significantly lesser than the previous ones yet shows excellent performance. Yes, it may not be as good as the ones we mentioned above, but it sure is well worth the money.
The LKR7DIX-11S also comes with trivalent metal plating which makes the spark plug last longer by preventing corrosion. The longer insulator nose prevents fouling, and the triple gasket seal is designed to eliminate combustion gas leakage. The iridium tip is 0.6mm thick and is laser welded, ensuring durability and consistent sparks to improve the overall vehicle performance.
Yet, with all these features, this spark plug is very much affordable, which makes it one of the cheapest but best Iridium spark plugs available on the market.
- Significantly cheaper than other Iridium spark plugs.
- Corrugated ribs and laser welded Iridium tip.
- Triple gasket seal.
5. Best Spark Plug from Denso(Platinum): Denso 4504
Denso is also one of the familiar and trusted brands in automotive parts, and this budget platinum spark plug is one of their best sellers, thanks to its superior performance. It has a twin-tip design which could only be seen in most technologically advanced cars only, and supposedly that is responsible for its enhanced performance and popularity.
Conventional platinum spark plugs use platinum electrodes, while Denso 4504 uses platinum on the center electrode and titanium enhanced alloy on the ground electrode, which is proven to increase durability and minimize erosion effectively. These spark plugs usually last more than 60,000 miles.
The Denso 4504 comes in a pack of 6 spark plugs, and the costs are pretty cheap compared to the performance and material. You can either change all of your spark plugs to get a sudden increase in acceleration and power, or you can change only the faulty ones and store the rest for future use.
- Lasts more than 60,000 miles.
- Twin-tip design.
- Titanium-enhanced ground electrode.
Frequently Asked Questions
When to replace a spark plug?
A spark plug is an essential component of any gasoline-powered motor or engine. Diesel engines do not have a spark plug, so if your vehicle/motor is diesel-powered, you don’t need a spark plug.
If your gasoline-powered engine is misfiring, or your car is showing a lack of acceleration, having trouble starting, showing low fuel economy, or if there’s a loss in horsepower, you might have to replace the spark plugs. And since your choice affects the performance by a good margin, consider buying one of the best spark plugs.
Besides, you should change your Iridium spark plug every 80K miles, Platinum spark plug every 60K miles, and Copper spark plug every 20K-30K miles. Cleaning the spark plug electrodes every 10K miles is a good practice, and will ensure a longer life.
What to consider when buying a spark plug?
There are different types of spark plugs, different in length, material, shape, etc. The first thing to do is to find the spark plug models that fit your vehicle, and then you should choose the best spark plug out of them based on these factors.
Material: There are copper spark plugs, called the ‘standard spark plugs’, and then there are spark plugs that are made of platinum and iridium. Mechanics will agree that iridium spark plugs are the best, then platinum and then copper, in terms of durability and consistency. Iridium spark plugs provide much more power, consistent sparks than the other ones, resulting in increased power, acceleration, and fuel economy. They also last up to four times more than the standard spark plugs. However, iridium spark plugs cost a little higher than standard spark plugs.
Durability: While iridium and platinum spark plugs last longer, some standard copper spark plugs will also last longer if they have yttrium or titanium coatings. However, iridium and platinum are still the best as they last around 80,000 and 60,000 miles respectively.
Gap adjustment: Many spark plugs come with pre-adjusted gaps between electrodes. We can’t say pre-adjusted spark plugs are the best, but if you haven’t adjusted one previously, it is better to choose a pre-adjusted spark plug. The gap is very crucial in providing optimum performance and even a minor misadjustment can cause serious misfires and a drop in fuel economy.
How do spark plugs work?
The gasoline needs to be ignited to convert it into a usable form of energy. The spark plug makes this possible by transmitting electrical energy between its electrodes, which creates a spark. Since gasoline is highly inflammable, even the tiny spark created by the spark plug will be enough to ignite the fuel. The energy due to the combustion of the fuel inside the combustion chamber moves the piston which drives the crank and gives the
Do spark plugs increase horsepower?
Yes, they do.
If a spark plug is worn out or clogged due to carbon deposits, the voltage supplied to it will not be enough to create a spark. If the spark plug does not fire continuously, some of the fuel will not be combusted, which results in engine misfires, poor fuel economy, loss in horsepower and even engine backfire. A clean and healthy spark plug is key to superior engine performance.
What are cold and hot spark plugs?
There are spark plugs designed to have different temperature tips – cold plugs have colder tips and hot plugs have hotter tips.
Spark plugs with cold tips are better for hot conditions. When the engine is hotter, the colder tips operate at lower temperatures, allowing the plug to remove excess heat from the engine efficiently.
Hot plugs operate the opposite way. They remain hotter even when the air-fuel mixture in the chamber is colder, and hence good combustion. Hot plugs are better for long winters, they offer better cold starts and engine performance compared to other spark plugs.
What are the signs of a bad spark plug?
The most common signs are a drop in fuel economy, poor acceleration, and engine misfires, especially when idling. The car will not accelerate as it used to and will be accompanied by occasional vibrations and jerking motions. An engine hesitating to start is also a sign of a bad spark plug.
How to install a spark plug?
This video from Autolite clearly explains the procedure for installing a new spark plug.
Some more high performance spark plugs
We checked some other iridium, platinum, and copper spark plugs also. They did not make it into the best 5 spark plugs list, but they are a great option if you don’t want to go for the expensive ones, or if your car uses a different model.
One of the top 10 spark plugs, the 6619 was a masterpiece from NGK. It ruled the amazon bestseller ranks for a long time due to its fine wire design. It has been ten years since its initial release, and yet it is still one of the best iridium spark plugs we can get on the market.
It comes in a pack of 6 and the costs are well justified by its performance. The NGK 6619 was proven to perform much better than the OEM ones, and that is one of the main reasons why it became so popular.
- Fine-wire design
- Lasts around 80,000 miles
- Pre-gapped at 0.043″
ACDelco is another trusted brand among vehicle parts manufacturers with experience of over a hundred years. The 41-103 from them is their bestselling iridium spark plug, and this one also boasts a fine-wire electrode, offering excellent engine idle stability and smooth performance.
- Fine-wire design
- Prevents combustion leakage
- Reliable cold starting
The NGK 5464 is a little older and it has been 12 years since its launch, but it is still a decent spark plug. It is compatible with many of the cars of the last decade, and the response from the community has been overwhelming. Everyone agrees that their vehicle showed a remarkable improvement in performance after installing this spark plug. It comes with trivalent metal plating, a long insulator nose, and corrugated ribs.
- Tapered ground electrode
- Trivalent metal plating
- Best spark plug for older vehicles
If you are not a great fan of NGK and Bosch, Denso 5304 could be a great alternative for you. This spark plug fits most cars of the 2000s and performs much better than the OEM ones. It comes in a pack of 6 pieces and each one is available at the price of a platinum spark plug.
- Smooth idle
- Improves power and acceleration
- Iridium tip
Costing only the price of a copper spark plug when buying a pack of 4, the NGK 7090 was the best platinum spark plug available on the market until recently and is still one of the best selling platinum spark plugs. This one is known to improve fuel economy and the power of older cars, and the corrugated ribs and specially designed insulator nose prevent most of the common spark plug issues.
- Improves fuel efficiency
- Trivalent metal plating
- Platinum tip
An incredible platinum spark plug at the price of a premium copper spark plug, the Bosch 4309 uses surface air-gap firing technology which provides multiple spark paths and hence a better fuel economy and acceleration. It comes in a pack of 4 and usually gives two times longer service life than the copper spark plugs.
- Surface air-gap firing technology
- Lasts 60,000 miles
- A notable difference in fuel economy
Bosch, a renowned brand on automotive parts, assures 5 years of satisfaction with this product. The double-platinum firing pin and the fine wire design of the center electrode are sufficient to give up to 3 times the service life than standard copper spark plugs.
- Double platinum electrodes
- Fine wire design
- 5-year performance satisfaction guarantee
Autolite spark plug review: Autolite APP104 Double Platinum
An affordable spark plug from Autolite with compelling features, the Autolite APP104 has full platinum tips and a necked-down center electrode. It has a high nickel alloy side electrode and a full copper core, which makes it perform better in all temperature conditions.
- Full platinum tips
- Necked-down center electrode
- Copper core
Even though it is cheap, this spark plug is worth more than the price. The electrodes are nickel-tipped, and the core is made of solid copper, making it last a little longer than the normal copper spark plugs. It uses high alumina ceramics for better heat transfer and insulation, and the triple gasket seal ensures that the combustion gas does not leak.
- Nickel tipped electrodes
- Triple gasket seal
- Alumina ceramics for insulation
A spark plug with the latest features, from one of the finest brands in this industry. This spark plug comes with dual ground electrodes, solid copper core, triple gasket seal, corrugated ribs, and a long insulator nose, which makes it capable of preventing the most common spark plug issues. It comes in a pack of 4 and is fairly affordable.
- Dual ground electrodes
- Corrugated ribs
- Triple gasket seal
Specifically designed for smaller engines and motors, the Champion RDZ4H is compatible with lawn, snow, and garden applications. The design is effective in resisting fouling and improving corrosion resistance.
- Resists fouling
- Good corrosion resistance
- Designed for smaller engines