Why upgrade your vehicle’s spark plugs?

Why upgrade a cars spark plugs?

As simple as spark plugs may seem to be, they play several critical roles in any vehicle – not least the literal creation of an artificial bolt of lightning within the engine’s combustion chamber. To enable a spark to be created and a ‘fire lit’ within the combustion chamber, the electrical energy (voltage) transmitted by the spark plug must be extremely high, amounting to anything between 20,000 and more than 100,000 volts.

If you are considering upgrading your own vehicle’s spark plugs, though, you need to be clear about your reasons for doing so – and whether a given spark plug is genuinely suitable for your vehicle, in light of how the latter may have already been modified.

Is that spark plug you’re considering still the right option?

Whenever an engine is modified, its characteristics are altered in some way. This means a spark plug that might have previously been ideal for the vehicle in question may no longer be so suitable once such changes have been made.

This is not to suggest, of course, that you shouldn’t upgrade your vehicle’s spark plugs, but it should nonetheless alert you to the importance of careful testing.

When you are making changes to the heat range of your spark plug, for instance, it is wise to err on the side of an overly cold spark plug, than an overly hot one. Whereas running too cold a plug can only lead to it fouling out, when a plug is too hot, severe engine damage can occur.

We would also urge you against making spark plug changes at the same time as any other engine modifications, given that if any issues then arise, you may end up making inaccurate or misleading conclusions about the likely cause. An exception to this would be if alternate plugs are included as part of a single pre-calibrated upgrade kit.

Understanding spark plug heat ranges

A spark plug’s ‘heat range’ can be defined as the speed with which the plug is able to transfer heat from the combustion chamber to the cylinder head.

The optimum combustion chamber temperature for a petrol engine is between 500 degrees C and 850 degrees C; this is the ‘sweet spot’ at which it is sufficiently cool to avoid pre-ignition and plug tip overheating – with the associated engine damage this can cause – but also hot enough to burn off the combustion deposits that are responsible for fouling.

Ultimately, a given spark plug can be described at the different ends of the spectrum as either a low heat range or a high heat range spark plug – these terms corresponding with ‘hot’ and ‘cold’ respectively. The former, as a rule of thumb, is associated with lower-powered engines, whereas the latter type of spark plug is routinely found in a high-powered engine.

Another way of seeing the difference between the two types is that a ‘cold’ spark plug transfers heat quickly from the firing tip into the cylinder head, thereby keeping the firing tip cooler. The ‘hot’ plug’s far slower rate of heat transfer, meanwhile, keeps the firing tip hotter.

Comparing the heat ranges of different spark plugs can be confusing, not least given that there is no single heat range numbering system used across the various spark plug manufacturers’ offerings. One manufacturer’s spark plug with a ‘10’ heat range is therefore not the same as another manufacturer’s ‘10’ heat range plug.

Make sure you purchase that ‘racing’ spark plug for the right reasons

When you are considering investing in ‘racing’ spark plugs for your vehicle, it is crucial to be mindful of what they will do, and what they won’t do.

Here at Progressive Parts, for instance, we are delighted to offer NGK Racing Spark Plugs that represent excellent uprated replacements for the standard spark plugs of such models as the Golf ‘R’ Mk7, Leon Mk3 Cupra, TTS Mk3, RS3 8V and RSQ3. These spark plugs have been designed to meet the rigorous standards that you would expect from the UK industry leader in this category.

However, NGK also does not pretend that its ‘racing’ spark plugs are any different in internal construction to most standard spark plugs; in any case, all of the brand’s spark plugs must comply with the same level of quality controls.

NGK also tends to warn against any expectation that racing spark plugs provide a means of ‘unlocking’ large amounts of horsepower. Even the most seasoned tuners generally invest in racing spark plugs for other reasons – for example, to ensure the more efficient removal of heat, or to provide sufficient spark to light all of the air/fuel mixture.

Alternatively, you might look to invest in racing spark plugs so that they’ll be able to better withstand the heightened stresses that are customarily placed upon the spark plugs of high-performance engines, or so that you can achieve the best possible piston-to-plug clearance.

Would you appreciate further guidance as to how to upgrade your own vehicle’s spark plugs to ensure you attain the results that you desire? If so, you are welcome to contact our team right here at Progressive Parts.

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