Best engine spark plugs 2021 - Denso, NGK or Bosch?

Heat number is one of the most important parameters for spark plugs, which many users ignore. This is a figure showing how quickly the candle heats up when the engine is running. More precisely, the time required for its incandescence. When the engine overheats, the so-called glow ignition occurs, which leads to malfunctions. To avoid it, it is important to choose the right candles.

The choice of glow number depends on what driving style you use:

Candles with a high glow number are called cold, and with a low one, respectively, hot. You also need to consider the size of your motor. The larger it is, the colder the candle is needed and vice versa.

For convenience, many manufacturers replace the figure of the glow number with the determination of the degree of incandescence. Be sure to specify this point in order to know the specific meaning, since the same figure for different brands may have a different designation.In our case, NGK 4629 C7HSA and Bosch SUPER 4 WR78 have the same glow number, 7 units, but in the first it is defined as cold, and in the second as medium. And the winner of the nomination is Denso with his 20 units. This is the most balanced candle in terms of glow number. It will fit most engines and different driving styles.

Spark plugs were invented many decades ago and until recently their design was considered complete. That is, there is nothing to add to it, it is perfect. But technology does not stand still, and engineers came up with the idea of ​​​​putting not one electrode, but several. We are talking about side electrodes - metal brackets into which a spark strikes. If he is alone, situations often arise when a spark is flooded or blown out. In this case, no ignition occurs. The driver may not even notice this, but one cannot but agree that such downtime has a bad effect on the motor in the long term.

This problem is partially solved by several electrodes instead of one. This increases the chances of the candle firing by a factor equal to the number of electrodes. That is, if there are three of them, then there will be three times less downtime. Of course, all these calculations are conditional, but one cannot but agree that a candle with a large number of electrodes works better. In our case, the winner is Bosch, using 4 side electrodes. The rest of the nominees share second place, as they have a classic design with one module.

It is possible to improve the operation of the candle not only by increasing the number of side electrodes, but also by changing their shape. There are several types of modifications: rounding, groove, bulge, hole.

It is difficult to say which of these forms is more preferable, but tests show that design changes can improve plug performance, and sometimes quite significantly. In our comparison, only one nominee decided to modernize the shape of the side electrode - this is Denso. It has a hole in the place where the spark is directed. The flash passes through it and the likelihood of fuel ignition increases. The rest of the applicants decided to leave everything as it is.

The thickness of the central electrode affects how quickly the ignited flame spreads through the cylinder. Accordingly, this affects the overall power of the engine. Feedback works here: the thinner the electrode, the faster the propagation, and vice versa. This is the reason for the fact that manufacturers produce platinum and iridium candles. These materials are denser in structure. If the standard thickness of a nickel alloy electrode is 2.5 millimeters, then for platinum it is already 1 millimeter, and for iridium it is even half as much.

But only nickel models of candles were included in our comparison, however, they also have a certain difference. Manufacturers Bosch and Denso decided not to experiment here. They have standard nickel electrodes with a thickness of 2.5 millimeters. But NGK uses a thinner module, only 1.5 millimeters. This size is already much closer to platinum, but wear will occur faster.

In order for the fuel injected into the engine to ignite, it is necessary for a spark to pass between the two electrodes on the spark plug. The length of this spark can be very different. To generate it, a high voltage is required, which forms the coil. In modern cars there is a large supply, up to 40 thousand volts. And it takes 20,000 volts to cover a distance of just 1 millimeter.

There is also a feedback saying that the smaller the gap between the electrodes, the more often misfires will occur. That is, the spark will be very small, and from time to time the fuel will not ignite. It turns out that manufacturers again run into the notorious balance. In addition, the gap increases over time as the center electrode wears out.Another reason for manufacturers to use denser materials such as iridium and platinum.

There are certain standards for spark plugs. The gap between the electrodes should be at least 0.5 and not more than 1 mm. Among our nominees, the NGK spark plug has the smallest gap - 0.7 mm. Such a candle will last longer, since the electrode will need more time to operate. Bosch has a slightly larger initial gap - 0.9 mm. And at the limit of permissible norms is Denso with 1 millimeter, respectively.

The most controversial and controversial issue, which is influenced by many factors. The same candle installed in an old VAZ and on a racing car will work differently. A lot depends on driving style. The fact that you inject fuel, an injector or a carburetor, and a dozen more factors. But each manufacturer conducts tests and, according to them, calculates the resource of his product.

So, according to Bosch, candles must work out at least 80 thousand kilometers. Both competitors have a little less: 60 thousand km for NZhK and 40 thousand km for Denso. It turns out that Denso are the weakest candles? Not certainly in that way. Recall that they won in the nomination "Incandescent Number". That is, they are designed for more aggressive driving. While longer competitors are rated for modest, careful driving.Therefore, if we take a hypothetical old VAZ without an injector, which does not drive above 60 kilometers and never gets stuck in traffic jams, then the life of Denso candles will be much higher.

But be that as it may, to determine the winner, we will use data from the manufacturer. In addition, our comparison includes the best brands that are not used to deceiving the consumer. If they write that the resource is 80 thousand kilometers, then the figure is real, taken not from the ceiling, but from real tests, even at the stand.

It’s not enough just to choose candles in a store or on the market, you also need to determine whether they are original or if they are cheap counterfeit. All our comparison loses its meaning if you run into a fake. After all, we are considering original models. Unfortunately, there are a lot of fakes on the market, and for all the nominees. This is not surprising, because the comparison included the best brands with high sales rates. Often a fake can be identified by eye. Even before buying it. You need to look at the following points:

• the quality of the casting of the upper terminal;
• flatness of the side electrode;
• visual evenness of the central electrode.;
• no obvious signs of marriage.

Top brands closely monitor the quality of their products, and if a candle with a crooked insulator or an unevenly welded protein electrode left the assembly line, it simply will not pass the quality control. If you see such a candle, it means that you have a clear fake in front of you. Also, a too low price tag should lead to doubts. Ask yourself why the seller, supplier, or manufacturer suddenly became altruistic.Yesterday they were selling these candles for a conditional 300 rubles, and today - for only 100 rubles.

As for our comparison, it is impossible to say which brand is counterfeited more and more. It is much more important how the manufacturer protects itself from such fakes. Bosch is the winner. Firstly, his candle has a complex design. Recall that 4 side electrodes are installed here. At the same time, the model is quite budgetary, which means that it is simply unprofitable to fake it. It’s easier to make a single-electrode Denso or NLC on your knee. Second, Bosch embossed the insulator and metal skirt with the logo. Yes, all this can be copied if desired, but at the end such a fake will cost much more.

Spark plugs come in different sizes and shapes. It is clear that a small-liter VAZ and a 5-liter Cadillac with an injector need different models with different skirt lengths and threads. In addition, there are different standards for wrenches and threads. To clearly understand how our nominees differ from each other, consider their main mechanical parameters:

So, we see that the first two nominees use the metric system, which is more familiar to us. While Bosch has slightly different standards. You will need a 1.5" wrench to tighten this candle. Simply put, in a car manufactured before 1990, that is, in the notorious VAZ, such a candle simply will not fit. She has a different thread pitch. It turns out that the German brand takes third place in the nomination. Next, consider two Japanese models.They have almost the same values, except for the length of the skirt. And here the Denso model looks more attractive. After all, if both options are installed in your engine, then the electrode and, accordingly, the spark of such a candle will be much closer to the piston, which means there will be fewer moments when the fuel does not flare up.

The simplest nomination that does not require detailed consideration. The cheapest spark plug from NZhK. On average, it costs 190 rubles per piece. Denso is a little more expensive, 230 rubles, and the German Bosch is approaching three hundred rubles, which makes it the most expensive among the presented nominees. However, this is not surprising, given the nominations in which this brand won, but the fact remains.

As you can see, the gap between the participants is small. Moreover, each contender won in the same number of nominations. The difference in the overall score is minimal, which tells us that all the presented candles are the best of their kind. They are slightly different.All have their advantages and disadvantages, but on average they are equally good and worthy of attention. Moreover, even Bosch, who lost in total to the rest of the nominees, has very significant advantages. For example, it has the highest resource and the largest number of electrodes, which makes the candle as productive and reliable as possible. But the price is right too. In general, whichever model you decide to choose, all of them are of high quality in their category.