Do Hotter Spark Plugs Burn More Fuel?

Do Hotter Spark Plugs Burn More Fuel?

Note: As an amazon associate I may earn a small commission from qualifying purchases if you click to amazon from my site and choose to make a purchase.You can read my complete affiliate disclosure for more details

Do Hotter Spark Plugs Burn More Fuel?

A hotter flame propels hotter sparks. This means that an engine will produce more power with a hotter spark than a colder one for a given amount of fuel (e.g., natural gas).

This is because the heat of the hot spark evaporates the fuel to create more gas molecules, which results in each molecule mixing with greater air molecules and combusting more easily.

More importantly, combustion occurs at higher pressures and temperatures inside the engine’s cylinders, allowing it to run faster and produce increased horsepower outputs.

Yes. Hotter spark plugs make more power for the same fuel. They burn more evenly with a shorter duration and lower emissions. Higher combustion temperatures raise the thermal efficiency of a spark plug. However, this is only true if the engine is already running at its optimum performance for given environmental factors.

For example, it doesn’t matter how hot your spark plugs are if you’re not using premium fuel.

Let’s look at the reason a hotter spark plug makes more power.

As the mixture reaches a certain temperature (depending on ignition timing and fuel-to-air ratio), a portion of it ignites as extremely hot and short-lived plasma.

This plasma expands while carrying some of the energy released when ignited initially into the combustion chamber, but only for a short time.

During this expansion, some energy is also used to heat the cylinder walls. In addition, like a real plasma, some of the energy emits in all directions as light.

Theoretically, if the temperature was high enough, and they made the plasma last a long enough time, this would transfer more heat to the cylinder walls.

A longer duration of controlled expansion would occur until it eventually burned out.

However, because this doesn’t happen, you remain with a non-ideal thermal energy transfer from the spark plug to the combustion chamber.

Therefore, a hotter spark plug has a longer duration than one that runs cooler. The temperature at which the ignition happens varies depending on the exact mixture ratio, fuel, and ignition timing.

This expanded mixture transfers some of its energy to other molecules in the cylinder by collisions.

These molecules hit other molecules, and thus, some of that energy transfers as well, statistically, until all the kinetic energy spreads evenly throughout the cylinder.

Can A Hotter Spark Plug Damage Your Engine?

Yes. As an older automobile ages, its parts wear out, and the spark plugs are no exception. If your spark plugs are old or faulty, the temperature of the sparks will be too high for your engine.

When you change a car’s spark plugs, you want to make sure that they’re compatible with the air-fuel mixture in your engine.

Spark plugs that are too cold can cause the engine to run erratically, often misfiring and stalling. Spark plugs that are too hot can damage your engine by burning the insulator and causing a fire.

A spark plug’s core temperature gauge measures the heat of the spark. In newer vehicles, the car’s computer automatically controls it. For older vehicles, the gauge will get exposed to the driver.

Do Hotter Spark Plugs Burn More Fuel?

Replace it if your spark plug gauge is stuck at a certain temperature. Also, if you notice any misfires or the engine sounds like it’s cutting out when it should run smoothly, change your spark plugs.

For older vehicles exposed to the driver with gauges, ensure that your gauge isn’t stuck at a certain temperature before driving your car. Also, check your engine.

The gauge may not be working correctly because of more severe problems with your car, so if you think it’s malfunctioning, bring your car to a mechanic and have them inspect it.

Replace your spark plugs if you notice any misfires or the engine sounds like it’s cutting out when it should run smoothly.

If the temperature of your spark plug gauge stays in one place, make sure that they are compatible with the air-fuel mixture in your engine before driving.

Do Colder Spark Plugs Make A Difference?

Yes. Spark plugs can help in the winter, but only if you know which ones to use. The colder the temperature is outside, the colder your spark plugs should be to help protect your engine.

I recommend switching to a colder plug for better performance if you have a cold engine.

Remember that it’s essential for whichever type of spark plug you use in winter weather to be at least 30°F below ambient air temp.

Keep in mind that colder spark plugs can’t withstand high temperatures and melt if exposed too long or run continuously at high RPMs with lots of throttle application.

The most common spark plug type is the platinum (or iridium) spark plug. The primary benefit of a platinum plug is that it can withstand higher temperatures than the standard iron spark plugs.

They cost more, but a platinum plug can run at much higher temperatures for longer periods and resist heat better than an iron plug.

The colder the temperature outside, the colder you should run your car to help protect your engine.

The hotter your engine runs, the colder air gets pulled into your engine, which pulls the heat out and cools down your spark plugs.

By running colder spark plugs, you can pull that hot fresh air out of the engine and put it back in to keep your engine from overheating.

The hotter fuel burns and higher temperatures you see under the hood, the more critical it is to run colder spark plugs.

When Should You Run A Hotter Spark Plug?

You should run a hotter spark plug when using a hotter engine. This is for four-cycle engines most commonly used in cars and motorcycles and some aircraft engines.

There is no faster way to improve fuel efficiency for your car than through spark plug tuning, so if this applies to you, consider the following information.

To know what spark plug size works best with your engine, look up the manufacturer’s recommended horsepower range of your model to determine the compression ratio before proceeding.

For example, the suitable horsepower range for a Honda Civic 2002 engine is 88-109 HP (the compression ratio is 9.4:1).

One measurement that you will see on a spark plug packaging is the heat range or the “R” rating. The hotter the plug, the higher this number will be.

As they get hotter, they also get more expensive. They have different levels of performance and have rates in degrees Fahrenheit.

A plug rated at 286 F is a high heat range, while one rated at 315 F is a low heat range.

Please take note that heat ranges do not measure how hot the plug can get before it starts breaking down.

A hotter spark plug will not last as long either because it will destroy itself.

It’s essential to find out the starting point for this number, and even more important is to know how it affects your engine for you to decide what tool you need for spark plug removal and installation.

Now that you have the correct heat range, you can proceed to the next step, which is spark plug removal. The steps for this are:

First, loosen the spark plug using a spark plug socket wrench and a ratchet. Use nothing other than your hands, as using tools may damage your engine.

You must remove the spark plug from its socket by turning it counterclockwise and out of its way.

With the spark plug already loosened, you can use a socket extension to remove it further by placing the end of this first. Then you can use a spark plug wrench to eradicate it.

Be careful not to drop it inside the engine bay, as this can be detrimental to your vehicle’s performance and require re-calibration of your ignition system.

Use only spark plug sockets made for spark plugs and remove them using your hands.

Once you remove the spark plug, please clean up the surrounding area. When you finish cleaning, you can install one of the new plugs. 

Do Hotter Spark Plugs Burn More Fuel?

Finish by tightening it in a clockwise motion until it’s completely tight and secure. To achieve the best results, ensure that it’s as tight as possible without stripping the threads.

Wipe any oil off your hands before touching anything else, and then recheck your work. 

Will A Hotter Spark Plug Burn More Fuel?

Yes. A hotter spark plug will burn more fuel. This is a common misconception that needs clearing up.

A hotter spark plug will increase the ignition speed, but the increased heat limits the combustion efficiency in that engine.

Heat is a requirement for combustion to take place, so you need to be careful about trying to run a colder spark plug on a hotter day.

However, spark plugs are not 100% efficient at converting electricity into power.

They only produce about 85% of the energy put into them, so a spark plug with a hotter temperature will use more electricity than needed, meaning that you would have to add more fuel and spark advance.

You can see this by testing the crankshaft output of spark plugs at three different temperatures ranging from 40ºC up to 160ºC (cruising, peak, and jet-set).

I could see no statistical difference between the crankshaft output at this test’s engine speed or temperature.

This is because several factors will determine the efficiency of a spark plug.

However, better spark plugs transfer more energy to the combustion chamber and burn hotter.

They also have more efficient ground straps, which take less energy to transfer current to the plug.

A colder spark plug will increase the crankshaft efficiency at lower engine speeds and temperatures.

Still, a hotter spark plug will increase the crankshaft efficiency at higher engine speeds and temperatures.

However, they offer the same efficiency and performance increase in engine speed and temperature.

Does Spark Plug Heat Range Affect Performance?

Yes. The spark plug heat range can significantly affect performance in a car. The colder the plug, the better the performance.

A hotter spark plug turns on quicker and has more power than a cooler one, which takes longer to turn on and has less power.

This also means that you will not have to change your spark plugs much since colder plugs will last longer than hotter ones.

Technically, if you get too hot in your car because of a faulty or failed engine, this is when you should replace your plug with a colder one.

Colder plugs are better since they provide more longevity, and heat will not affect them. This means that they will not burn out as quickly as hotter plugs.

An excellent way to test your spark plug heat range is to take a piece of paper, put it over the cooling area, and then turn on the ignition.

If the paper catches fire, you might have a colder plug that can prevent this from happening.

But if you do not have a piece of paper over the cooling area and see a lot of smoke, then this is a sign that something is wrong with your plugs.

You should change your plugs more often when they are hotter than they should be.Your plug can last much longer because the heat will not affect it when this happens.

There could be many causes for this, though, like faulty or worn components in your car. It is good to check your car’s plugs regularly since they are easy and quick.

You will also know how often you should change them. If you use the right oil in your car, this will help.

How Can You Tell Which Spark Plug Is Hotter?

While it’s true that you can’t tell which spark plug is hotter by feeling them, you can use a spark plug tool to check their temperature.

Your manual will usually have a table of the approximate temperatures for each engine type. If the one you want to check is white-hot or glowing red, it’s too hot.

If it’s an orange glow and mostly cool to the touch, then it’s ready.

You can preheat the spark plug before looking at the actual plug. If this works for you, then go for it.

If not, then use a thermometer probe to check the plug’s temperature and let it cool down until the next time you want to check it.

How To Do It:

To check your spark plugs before starting a fire, first, remove them from their cylinder heads and set them on a heat-resistant surface.

If you’ve never checked your plug’s temperature, here are some tips:

– If it’s knurled (or notched) and fits perfectly, it’s too cold. If not, use a screwdriver to prise off the outer black ring and check.

– Black wires have a higher resistance than the others because the electrode is thicker. You can tell which one is hotter by pressing harder on the hot one by touching them.

– If it’s got a blue wire on it, you have to screw the tip on.

– If you know which plug is from the diagram in your manual, use a screwdriver to prise off the black ring.

– If you want an easy way to check a plug afterward, slip a bolt between the bottom of the stainless steel packing nut and the spark plug.

Place your hand over both parts and see if they glow hot. If not, then it’s cool enough to go.

Once you’ve figured out the plug wires, it’s time for the fun bit. Wear goggles and a fireproof glove.

Warm-up your spark plug before trying to do this to avoid injury when you burn yourself or slip.

When Should I Run My Spark Plugs Colder?

You should run your spark plugs colder than recommended in your owner’s manual as a general rule. Conditions vary, though, and several factors impact when you should run your spark plugs colder. These include:

The driving you do. You use spark plugs in specific temperature ranges—the colder end for acceleration and the hotter end for the cruise.

If you stop-and-go driving a lot, you’ll want to run your plugs cooler than if you do mostly highway driving. The hotter the air and fuel mixture entering the cylinder, the colder you should run your plug.

The type of cylinder head you’ve got. If you have an I-beam or upright cylinder head, you probably want to run your plugs colder.

However, the Mach 1s with the early style wedge head camshafts run the plugs hotter than most other 289s.

The type of ignition system you have. The hotter the spark you have, the hotter you should run your plugs.

If you have a standard points ignition or a Mallory HyFire electronic ignition, you’ll want to run your plugs hotter than if you had an MSD or Crane coil system.

Do Colder Spark Plugs Make More Power?

No. Colder plugs work better in colder climates and colder weather because their resistance is lower in the cold. However, this does not mean that they have more power.

Cold plugs work best on gasoline engines only, and you should not use them on diesel engines.

Colder plugs are also marketed to reduce pollution from the exhaust, but there has been no evidence that supports this claim.

Cold plugs are plenty old enough for thorough testing for pollution control, and there is no sign that they do anything to reduce emissions.

It’s also a waste of money. Spark plugs last about 30,000 miles on average and cold plugs don’t make them go any further than regular plugs do.

Most car manufacturers recommend using the same heat range spark plug as the engine.

If you use a replacement plug of a different heat range, you may experience premature wear on your piston rings, leading to lower performance or severe engine damage.

Here are some tips on how to choose the correct heat range spark plug for your car:

• First, determine whether the engine is a gasoline or diesel engine. If it’s diesel, look for spark plugs made for diesel engines.

• If you are installing a new set of spark plugs or replacing your old ones with a different type, buy two different heat ranges to alternate between them every other time, depending on the weather.

• The whole idea of heat ranges is to allow you to see how the plug will perform in various conditions. This makes it easy to get the best performance and engine protection out of your car.

What Does 2 Step Colder Spark Plug Mean?

The two-step colder spark plug means the engine will fire off twice before reaching the average operating temperature.

This is necessary for cold weather when the air is thicker and needs more power to fire off. It also helps to avoid fouling plugs and opens up a little extra heat range in colder weather.

This also helps with the fuel mileage, as the car will start running better as it warms up. The first two starts are kind of rough, but after that, the car runs like a dream.

I have used a 2 step colder plug before, and they worked great. The cold weather I was driving in was so bad that the car would take on a severe slushy appearance even in the daytime.

It also ran a little worse than usual, but after 20 minutes, it would be back to normal.

I had to remember to warm the plugs up before starting again, though, and it was one of my novelty winter plugs.

Are NGK Spark Plugs Pre Gapped?

Yes. NGK Spark Plugs are pre gapped. This means they have a proper gap already set before you receive them. They are not user-adjustable, and you must install them without modifications to the gaps.

Your best option for sparking plugs would be to have your engine tuned to calibrate the timing and fuel injection system properly to allow optimum performance from your NGK Spark Plugs.

– The Spark Plug Gap is the distance that a spark plug has to travel from the electrode to the top of the combustion chamber.

This gap is how they have pre-set spark plugs to provide optimum performance. NGK Spark Plugs comes with this gap already set to provide optimal performance.

If your engine were defective or improperly installed, you would inevitably need to make modifications to allow for optimum performance.

Your best alternative is to talk with a professional mechanic who can properly install your NGK Spark Plugs.

– To benefit most from this gap, you need to ensure the tuning of your engine is correct and that you have the latest fuel injection system installed.

Contact a professional mechanic regarding your specific needs to perform at the optimum level so that the spark plugs will perform.

– NGK Spark Plugs are pre gapped. They come with a proper gap pre-set for optimum performance of your engine/ vehicle.

This means that you do not need to adjust the gap, nor should you attempt to do so.

The gap provided by NGK Spark Plugs is for the proper performance of your vehicle and will make no difference in terms of the life of your spark plugs.

– Your best option for installing your NGK Spark Plugs appropriately is to seek a professional mechanic who can properly tune your engine.

Adjusting the spark plugs yourself is not an option, as it will most likely void their warranty and may push your plugs out of adjustment over time.

– NGK Spark Plugs come with a pre-set gap that prevents you from setting the gap yourself.

This means that even if the spark plug gap is out of adjustment, you won’t need to adjust the gap yourself.

If your engine were defective or improperly installed, you would inevitably need to make modifications to allow for optimum performance.

Do NGK Spark Plugs Add Horsepower?

Yes. NGK Spark Plugs improve the display of your engine by smoothing the operation and boosting acceleration, but they also increase your car’s fuel economy and durability.

The company that makes these plug sets always have high quality and robust designs, so auto manufacturers like Honda adopted them as standard devices.

But even if the auto manufacturers use them, it doesn’t mean that they’re suitable for your car.

Using NGK spark plugs, you might have noticed that your car’s acceleration begins to show its effect after a few days of driving the same car.

This means that the spark plugs are working effectively and helping to make the engine run smoothly.

The more sophisticated the plug set is, the more stable the engine will be and the more efficiently you can drive your car.

Do Iridium Spark Plugs Increase Horsepower?

Yes. Iridium spark plugs are the best option for high-performance engines. The iridium alloy is the fourth densest element in the periodic table. It possesses a higher melting point.

When ground down to a microscopic level, it will heat quickly.

These properties make iridium plugs ideal for high-performance engines because they provide high voltage for faster ignition timing and improved fuel efficiency.

The iridium heat range is beyond the capabilities of other spark plugs, and that’s why they’re the only spark plugs to use. Iridium plugs give you more power in a shorter amount of time.

For example, iridium plugs will last fifteen times longer than a standard set for start-up torque and top-end horsepower.

If you have bought a new car, this is a good thing since it will get you to the finish line faster than before and give you more power.

Most iridium plugs are for only professionals to install, although some are for the do-it-yourself crowd.

You can further customize iridium plugs to your car’s power needs based on the amount of platinum added.

The process for installation is the same for all iridium plugs, so the only difference between them is how much platinum they have added to them.

Platinum makes the iridium material harder and more durable than other spark plugs.

Platinum adds more power to engines because it increases voltage when compared with a standard set of spark plugs, making every horsepower a better high-performance power.

Why Would One Run A Hotter Spark Plug?

Running a hotter spark plug can significantly cause less wear and tear on the engine, regardless of engine speed.

One study found that even after just a few minutes of driving at 4000 rpm, it showed 50% less wear than the stock spark plug.

There are many benefits to running a hotter spark plug, including increased gas mileage, reduced emissions, and increased power output.

If your car has a performance chip on its ECU, it can run with a hotter spark plug.

But it is good to check with the manufacturer of your spark plugs before doing this because some spark plugs do not mind running at a higher temperature and will be more likely to wear out than others.

The typical reason for changing a stock spark plug is because one electrode has become too worn to fire up the combustion chamber properly, resulting in a weak spark.

This causes engines to run poorly and, sometimes, can cause complete engine failure.

However, this could be the right solution if you run an engine you know well and have plenty of horsepower but are missing the last bit of performance.

Running a hotter spark plug will increase fuel mileage since the combustion chamber is already hot and burning the engine.

In addition, some higher-performing engines can burn a wider variety of fuels, from methanol to ethanol, but still, get limits on the firebox size.

Over time, this can wear out plugs initially designed for a flammable gas such as gasoline.

You can resolve this by changing the plug to a plug rated for higher octane, which will allow the engine to run better and more efficiently.

This can also resolve an ongoing problem of flooding in some engines when the fuel mist in the combustion chamber causes an excess release of hydrocarbons (HC).

The extra HC has no place to go inside the combustion chamber, so it builds up and restricts airflow in and out of the engine. This can cause stalling or sluggish performance.


Spark plugs are an essential part of your engine, and they need regular replacement. Iridium spark plugs are the best option for high-performance engines.

But other options work well depending on what type of vehicle you drive.

However, if you want to improve your current horsepower, iridium spark plugs will give you the best bang for the buck.


Hi! I' am Tom. I faced many questions from customers about different products, and there was hardly any help on the internet. After learning all the things about these products as a manager the hard way, I decided to start a blog and help other people.

Recent Posts