Engine & Equipment

The Best Car Spark Plugs (TOP 10) Review 2020


Like many automotive other parts, spark plugs are consumables, thus must be replaced after a certain time. Here you can be guided by mileage or the sound of the engine. However, when it comes to replacement, everybody has a reasonable question: which car spark plug is the best?

We have gathered the best spark plugs on the market and reviewed them in order to spare your time so you’ll be able to choose the needed item just like that.



A spark plug is a simple and inexpensive element: ease of starting the engine, power and fuel consumption, stability depends on it. The major aim of the spark plug is to create a spark at the right time. The plug is connected in a metal case-glass to the engine, then to a metal body, which, in turn, is connected “to ground” of the body.

No matter how good the spark plug is, additional reliability will never hurt. Several electrodes are a kind of insurance against non-ignition: the discharge will pass between the closest pair of electrodes. And, of course, at the same time, they will gradually degrade (oxidize, burn out). The plug must be periodically calibrated if there is one mass electrode, establishing a normal spark gap. However, several of them become a reliable guarantee of ignition: when one fails, the next continues to function. When one of them becomes dirty, the spark naturally “jumps” to the neighboring. The life of the spark plug is naturally being extended. However, in multi-electrode plugs, there is another important plus.

In a conventional plug with one electrode, it closes the central one. Then the ignition of the air-fuel starts from the side, where there is a gap between the two electrodes. The side electrodes are located around the circumference of the central one in the spark plug, and the ignition starts in the central part of the spark so that the flame spreads evenly. The difference is calculated in a couple of percents, but it is. There is a better combustion process, more power, less fuel consumption. Multi-electrode plugs are not much more expensive as single-electrode counterparts, while they work longer than two times, often providing a slight improvement in motor stability.

Things to Watch Out For

  • The turn-key size (diameter of the hexagonal extension of the corps) is taken into account during installation for the selection of a suitable tool.
  • The length of the threaded part. The exact match is required when installing the plug: if you take a very long plug, it will be screwed too deep into the combustion chamber, which will violate the calculated distribution of the flame. And the piston can hit, which will damage it as soon as possible. A short plug will not provide high-quality ignition: incomplete combustion will occur with all the ensuing consequences.
  •  An overly hotplug cleans well but increases the risk of ignition. Visually, it can be determined by the light (white) insulator and black oxides on the electrodes.
  • Too weak tightening won’t provide sufficient sealing in the corps, and too tight will at least break the plug, and at the most will damage the thread of the plug well. In the absence of a torque wrench, an indicator of the tightening angle is used: the plug is twisted to the indicated angle with a simple key.
  • The cause of premature failure of the spark plug is the incorrect choice of spark plugs relative to vehicle parameters.
  • Properly operating SP will be clean, without oil or carbon deposits, the insulator cone is yellow or light brown, with fully working electrodes that retain their shape and spark gap.
  • Too “cold”: the plug quickly covered with soot covering the electrodes. Such a plug will visually be dark, smoked, with a black layer on the body, insulator, and electrodes.
  • With prolonged overheating of the plug, there is a danger of complete burnout of the electrodes, overheating and damage to the ceramic insulator. If fragments of a ceramic insulator get into the combustion chamber, they erase the engine, rendering it completely unusable.
  • Seal type: cone or ring. It is also determined by the design of the engine, and the installation of a non-native plug will not allow the motor to work normally.
  • The diameter of the threaded part. Everything is clear here: it should correspond to the diameter of the thread of the plug well, without the slightest deviation.

Technical Terms

Ignition occurs with the help of electric discharge with a voltage of thousands, or even tens of thousands of volts, formed between the electrodes. The plug includes:

  • insulator
  • pin output
  • insulator fins
  • metal center and side electrodes
  • sealant

The contact group consists of one central and one or more side contacts coated by spraying. Ceramics plugs can withstand very high temperatures, as it is a metal of high heat transfer.

Thread (Diameter) is the diameter of the plug which is measured across the thread.

The standard thread is as follows:

  • M14 x 1.25mm
  • M18 x 1.5mm
  • M10 x 1.0mm
  • M12 x 1.25mm
  • M8 x 1.0mm

The plug’s seat is the part in contact with the engine, with its head of the engine. It happens:

  • Tapered / conical,
  • Flat / gasket

Hex size is the size of the key for the nuts, which is necessary to screw the plugin hexagon mounting.

The tip or firing end is the tip and its shape. The cork that you step on provides a good fire.

Tip or firing ends are:

  • recessed;
  • projected;
  • not projected;
  • extra projected.

Resistor reduces electrical noise. This is necessary in order so your engine delivers correct performance. Otherwise, vehicle malfunction can easily occur. Also, the car may be immobilized.

types of spark plugs

Types of Spark Plugs

Spark plugs are divided (depending on the metals used in the electrodes) into:

  • iridium;
  • platinum, silver, gold, etc.
  • ordinary copper

Against this background, a separate group with a central electrode is made of expensive materials: iridium, platinum, alloys with the addition of silver.

This SP came to us from the world of racing. As the competitions show, the engine gives out more power if the SP has sharp, thin electrodes: then the spark comes out more powerful, gives a good arson of the mixture, which in turn has a beneficial effect on the engine’s output.

In addition, a charge (spark) with great power cleans the electrode on the center better, literally tearing all deposits, dirt, and soot from it.

In fact, designers tended to make the electrode in the center very thin. To solve these problems of overheating and erosion of it, special materials were required: iridium, platinum.

Copper plugs are inexpensive. They are standard. 

Plugs are divided into:

  • two-electrode
  • multi-electrode
  • flare
  • plasma

Two-electrode plugs – a classic option. Multi-electrode plugs – an improved circuit. The central electrode is still one, and the side ones are two, three or more. With this scheme, sparking becomes more stable.

Also, plugs can have V-shaped or U-shaped grooves on the electrodes. It increases the flame size (at low speeds the engine works better). Also, there are spark plugs with a protruding electrode (apply only to certain engines).

Product review

NGK 6619 Iridium Spark Plugs LFR6AIX-11

Weight is 11.5 ounces. The central electrode has a tip made of iridium. The thickness of the electrode is 0.6 mm. The spark spreads better than in previous models, thus it provides high performance. 

This product is recommended because of the iridium pad that provides good engine performance.

• Particularly thin central electrode 0.6 mm
• Protection against corrosion and erosion
• Central electrode with iridium soldering
• The price is relatively high
Bosch 4417 Platinum+4 FGR7DQP

1 piece per pack. The design is modern and at the same time simple. The tip of the plug was redesigned, and now this model is unconventional. The electrodes (4) are coated with yttrium. Weight – 0, .32 oz.

It is very easy to work with this model. You just need to enable it, no configuration setting required. Performance is provided with a stub. This allows you to do without platinum and iridium. The service life is long. Operating costs are low.

Recommended because no configuration is needed.

• The manufacturer is a German company
that has gained market credibility
• The spark is very powerful
• Minimum settings, installation is simple
• There is only one plug
• The price is relatively high
NGK 7090 BKR5EGP G-Power

The modern design. Created from alloy. It has a thin tip of the electrode. Weight is 1 lb. Laser tip welding.

High performance at a low price. Platinum is on the tip of the electrode only, 0.6 mm thick. Power is less, but performance is greater. Therefore, the engine starts quickly, the efficiency is great.

Recommended because the work efficiency is high.

• Platinum 0.6mm tip • Platinum is only on the tip
Denso (4504) PK20TT Platinum TT

1 piece per pack. Two tips, central electrode made of a platinum, ground electrode made of titanium. Fuel is well saved, and the engine starts quickly. Alumina powder insulator to withstand the maximum load. The materials are very modern. The plug has a weight of 0.32 oz.

The performance is good. Under normal driving conditions, there are no problems.

Recommended because of platinum twin tips. This material is very good, almost on par with iridium.

• Platinum x2!
• Purified Alumina Powder Insulator
• 11mm Electrode
• Single Plug
Champion RE14MCC4 (570) Copper Plus Replacement

Product weight 0.8 oz. Its design is reliable, tough. The price of the device is low because the tip is produced of copper. The resistance of corrosion is integrated.

A good for an old car with a copper requirement. Life is high.

Recommended for old cars. An innovative model is more suitable for a new car.

• Low price
• High efficiency,
• It can be used to operate an old car
• Copper tip
Denso (5304) IK20 Iridium Power

Iridium tip. The electrode width is 0.4 mm. Product Weight 5.6 oz. One in the pack. The device is considered premium.

Engine performance is very high because the electrode is too thin and the tip is made of iridium.

Recommended due to high engine performance.

• The electrode is very thin
• The performance is very high
• Laser design
• The quality is very high
• The price is high
Motorcraft Spark Plug SP546 Set Of 8

The packaging is original. The materials are of high quality, consistent with current trends. Sold with a 1-year warranty. Weight 6.1 oz. High strength steel, the platinum gasket on both electrodes. Materials are corrosion resistant. The service life is long.

High performance. Designed specifically for Ford, Lincoln, and Mercury autos.

• With a guarantee for 1 year
• Long service life
• Platinum
• Guaranteed to fit Ford, Lincoln, and Mercury
NGK (7092) BKR6EGP G-Power

Platinum Alloy. The tip is very thin, 0.6 mm. Pack of 1. laser welding. Stable spark, durability. Corrosion protection is provided by a trivalent metal coating. Gas leakage is not possible due to the triple seal. Weight 1.92 ounces.

The car starts easily. The engine runs efficiently. Emissions are getting smaller.

• The tip is very thin, 0.6 mm,
• Platinum
• Weight 1.92 ounces
ACDelco 41-103 Professional Iridium

6 pieces per pack. The sealant blocks radio frequencies that affect car work. Weight – 6.4 oz.

The engine is smooth and stable, thus the car accelerates quickly. The cold start is reliable.

• Iridium • The life is relatively short
Gearwrench 80601 SET SKT MAGNETIC 5PC

The kit has a spare 5PC clip. The design access to a hard-to-reach spark plug is always free. The magnet insert holds the device. A rubber insert is installed to protect it. Material – alloy steel. Weight is 1.5 lbs. One device is in one package.

High performance. Long service life, high strength due to steel casing.

Recommended because it has a high service life.

Comparison Table

ProductWattageLife Expectancy
Denso (5304) IK20 Very highLong
NGK 7090 BKR5EGP GreatLong
Bosch 4417 PlatinumVery highLong

Our best choice

The major thing to remember here: no matter what the plug, if it is chosen incorrectly, this will certainly affect the operation of an engine. 

The cheapest plugs are two-electrode, one-metal. The presence of a larger number of electrodes will positively affect. The same can be said about electrodes, the working parts of which are made of precious metals.

Flare and plasma plugs do not have side electrodes in the usual sense of the word. The occurrence of sparks here occurs with the help of a conical resonator. Ignition of the fuel occurs evenly and continuously.

This is the best spark plug option to date, according to manufacturers. But according to motorists, this is not so! 

Companies do not stop there but continue to improve their products. For example, Denso Iridium Power plugs are distinguished by a very thin central electrode – only 0.4 mm: this provides them with excellent self-cleaning, minimal erosion, and a powerful spark.

Bosch hid the electrode almost completely in a ceramic base: this reduces the effect of high temperatures and, consequently, electrode wear.

And, for example, Beru UXT plugs are distinguished not only by their material (platinum and titanium) but also by their “multi-electrode nature”. In short, thanks to the high price of the part, the engineers got complete freedom of action here.

Denso introduced the TT (Twin Tip) spark plugs. They are distinguished by small, thin “growths” on the electrodes of ordinary metals, alloys.

The result is a PS that breaks between two thin points: similar to iridium or platinum spark plugs (with their thin central electrodes), but the solution price is much lower.

All leading spark plug manufacturers are working on such improvements today:

• Bosch;

• Beru;

• NGK;

• Denso;

• Brisk and others.

To be frank, there is no easy answer on ‘how to choose spark plugs for a particular car’ question. You need to refer to the technical documentation and pay attention to reviews.

 In the official manual, which every motorist has in the vehicle, there is a list of products recommended by the manufacturer. If such a thing is not found in the car, you can purchase a set of plugs according to the model installed on the engine. However, this method can be used far from always, there may be devices unsuitable for use on this model of the power unit. In the absence of the necessary data, their search can be performed on the Internet. 

The selection of spark plugs can be made according to the results of a study of the official website of the car manufacturer. Here you can find all the necessary data to find the most suitable set of products. In addition, on the Internet, there are websites of the largest manufacturers of spark plugs NGK, Bosch, Denso, and some others, where you can select spark plugs online by a brand of car, motorcycle or other equipment.


Why are plugs thinner and thinner?

The only place to put a plug on the modern engines with four and five valves is the center of the combustion chamber. The plug is screwed into the cylinder head through the well of the plug, which “steals” space at the valves and the cooling system. That is why it is necessary to make increasingly thin plugs and small diameter wells.

What is named the "heat range"?

This figure depends on the spark plug nose length. The heat will move more and farther from the tip when the nose is longer. Such a plug is hotter than one with a short nose.

What is the working temperature of the spark plug tip?

It should be from 840 °F to 1550 °F. This is regardless of where the plug is placed: in a car or in a lawnmower, for example.

What is a regular plug and a truck plug?

A truck plug is intended for trucks, SUVs, pickups and other vehicles. Its electrodes are larger and the ceramic insulator provides strength.

What spark plug gap is needed?

The factory always recommends some specific parameters. It applies to the spark plug gap as well. If there is no opportunity to follow the exact instructions, you need to take a plug with a difference of no more than +/- 0.008″ from the recommendations.


So, when choosing plugs, follow the recommendations of the manufacturer and reviews on the Internet.

A spark arises as a result of the appearance of a powerful electric discharge between the electrodes. Auto spark plugs cannot serve constantly, it is necessary to replace them with new ones. The replacement period for plugs varies depending on the type of PS, the material from which they are made, as well as the conditions of use. Standard plugs should be replaced at every scheduled inspection or if you surely know they are worn-out. If you do not do this, it will become more difficult to start the engine, cylinder malfunctions, increased fuel consumption, and other unpleasant consequences – and the cause of all – are faulty spark plugs. The price of one plug, which was not replaced on time, is incomparable with the price of losses during the repair. The best SP is able to maintain operability during mileage up to 90 000 kilometers. Typically, iridium and platinum spark plugs have these characteristics. They are designed and made with the best technologies and are able not only to ensure long and productive system operation but also to reduce fuel consumption, as well as positively affect engine power.