Auto Trends

The Odd Bunch

Air Gap-

This plug takes the problem of having a firing electrode in the way of the igniting fuel/air mixture and gets rid of it all together. Primarily use on racing engines, the surface air gap plug instead uses the body of the plug as a ground, which exposes the spark better and creates the most complete burn possible.

This design is well documented to provide higher horsepower, better mileage, and reduced emissions on an engine designed for hard core performance. Some racers have been known to just cut the ground electrode of a spark plug all together to create one of these type plugs. The problem with this design, is this is not everyday friendly. You would not want to drive to work with these plugs as they could cause a variety of problems with your engine and ignition system.

This plug type it best used on the track and not on the road, although there are rotary engines that can use spark plug variations to this design. Fundamentally, the multi ground plug configurations featured in Part 2 uses the same basic idea, but with a lot more control over the gap from which the spark jumps, making it safer for your engine.

DiamondFire-

This is the basic core design of the E3 spark plugs, which utilizes a sort of diamond shaped center hole where the electrode is. While the jury is still somewhat out on weather this technology actually works, there is some logic to their design which would say it is possible it could give a more complete burn and therefore add a few horsepower, better emissions, and better efficiency.

However, the extra metal around the firing electrode may also shroud the ignite of the fuel/air mixture and therefore actually hurt your performance. With this said, it is probably possible that this design may sometimes offer positive results for some engines and negative for others. At $6 a plug, we leave it to you to decide if it is worth the experimentation.

SplitFire-

While the Splitfire design has been documented to not add much of any potential over the typical spark plug design, some people still swear by them. They were involved in a class action suit awhile back which claimed that they did not have the proper information to back-up their claims of increased performance and efficiency.

They ended up paying those involved with the suit who had bought the plugs before December of 1997. While we’re not saying that there is never applications where this design might work, we are saying that the odds are certainly not in your favor of finding one.

Indexing-

This is an old racers trick that has worked fairly tried and true over the years, although sometimes it works better for some engines than others. You might be looking at 1 horsepower for all your hard work on up to as much as 5. The basic idea of indexing is to position the spark plug so that its gap is facing the center of the cylinder. You’ll want to also favor it slightly towards where the exhaust valves of the engine.

The key to efficient spark plug operation is to open the flame kernel so it can receive a complete burn. If the firing electrode is in the way, it may block the igniting of the mixture, reducing the potential of the burn. This is how indexing plugs works, by placing the open portion of the electrodes right where it needs to be, in front of the exhaust valves, so they can operate at their greatest potential.

Indexing can be done in two basic ways. Either buy a lot of plugs and try several until one twists in at the right angle, or use special copper washers you can place over the plug that compress as you tighten and allow you to set your plugs at just about any angle you need.

(Stay tuned for Part 4 to learn the steps for indexing your plugs)

In Summary-

There is no real trick to spark plugs… and there is not real magic to their design. The standard plugs are usually all you would ever need, although sometimes its fun to play around with some of these high tech designs, just to see what happens… you never know, you just might find something that your engine likes!

(…to be continued)

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Platinum-

Most long life spark plugs use platinum due to its high melting point. This makes a spark plugs life much greater than the conventional copper, due to the fact that it can hold up so well to the constant heat.

Platinum plug prices go anywhere from around $2 to upwards of $12, and the difference is the amount of platinum used. The more platinum used in the plug, the longer the life it will have. Some platinum plugs today boast they are good up to 100,000 miles.

Iridium-

Iridium is the new platinum. We say this because when platinum came out compared to copper it was superior in many ways. Iridium is said to be 6 times harder and 8 times stronger than regular platinum, which means that spark plugs can have even finer electrodes than ever before and still have excellent wear characteristics.

Iridium is a very costly, so $14 and up per plug is quite typical. Many enthusiasts love iridium plugs and have nothing but positive things to say about them. They will definitely outlast standard plugs and because of their hardness, they will not wear down overtime causing the plug gap to widen and subsequently the cylinders not to fire at their optimum.

Multi-ground Plugs-

While some motors, such as the rotary design specifically require multi ground electrodes, their popularity has extended through many engines. The design of multiple electrodes is meant to limit the amount of wear that occurs of the tip of the firing electrode by offering several several electrodes to fire from.

One of the biggest misconceptions of these plugs is that they must fire from all tips, therefore creating several sparks. This is not the case. There is only one spark that will appear out of one of the tips per engine revolution, which is how these plugs extend their useful life, by spreading the amount of fire time between 2, 3, or even 4 firing tips.

While these plugs do last longer than traditional and come pre-gapped, which makes them easier to install, there has never been any real conclusive evidence of much of a performance gain by the use of these.

Cut-back Plugs-

These plugs bring memories back to the old muscle car enthusiasts. You can purchase these, but often what people do is take a regular set of spark plugs and grind the firing tip back until it is just with the very edge of the electrode.

This design has shown a pretty consistent couple of horsepower (1-3), as well as better throttle response. It does the same thing as all the specialized plug, opens the area of the kernel flame. In fact, it often works better than some of the fancy designs.

Instead of trying to re-shape the ground electrode, you are simply ridding the electrode hang over all together. The only drawback is because you are significantly reducing the contact area of the firing tip where the spark jumps, these plugs tend to wear out a lot quicker than a standard plug.

(to be continued…)

Well, not quite everything, as there is a lot to tell. But today we are going to feature some of the choices you have when it comes to replacing your spark plugs. It is important to note that while no spark plug can ever make a really huge difference in the performance and gas mileage of your vehicle, there are definitely proven designs that have shown increased service life, as well as even a very moderate increase in performance.

Before you can truly appreciate some of these uniquely designed spark plugs and how they theoretically can improve engine performance, we must first look at what exactly a spark plug does. A spark plug is the link between your vehicles ignition system and fuel and air intake. Once the mixed air and gas from your vehicle are brought to your cylinders it is the spark plug that ignites this mixture causing the force that power the pistons to turn the crankshaft.

While there are thousands of volts shooting through a spark plugs electrode, it is not the voltage itself that is the most important part of lighting the mixture as is the heat generated by the plug. This is why certain spark plug designs are theoretically better than others.

If the contact surface between the electrode and flame are opened, leaving more open area between the two surfaces, then the heat created will remain more constant, and not be reabsorbed by the electrode. When an electrode is completely covered by the flame, as in a standard spark plug,

the heat build up is slightly squelched and therefore a complete burn may not always occur.

Let’s see what some of our options are to help with this problem:

U-Groove-

This design made famous by Denso puts a U-Groove within the underside of the electrode in order to open the area of the flame kernel. There have been some decent reports that have shown that this configuration can improve acceleration and throttle response slightly.

V-Power-

A similar idea as the U-groove except the center electrode is cut into a V Shape. NGK has a nice line of V-Power spark plugs whose design has received similar results as the U-grove.

Fine Wire/Tapered Cut Electrode-

The main advantage of these types of spark plugs is number one, it opens the area for the flame kernel. Two, the smaller area of the electrode requires less voltage to jump the gap, so there is less chance of misfire.

Due to the smaller area of metal, the typical copper electrode is not recommended as it would wear too quickly, so one of the popular exotic metals is preferred, such as platinum or iridium. These hard metals maintain and often surpass the traditional longevity of the typical spark plug even with the reduced electrode area.

(to be continued…)