Choosing a racing plug

Choose the right spark plug for your engine based on heat range and electrode design, engine tuning, and racing conditions.
Racing plugs for both two- and four-wheel vehicles have been developed and designed for use in engines that have been fine-tuned to achieve maximum power under specific racing conditions. Racing plugs differ from standard plugs, both in appearance and performance, and often sacrifice plug life, and efficiency at low-speeds for optimum performance and durability under torturous racing conditions.

Heat range

Spark plugs with a higher heat-range number have superior cooling characteristics.

Electrode design

Engine tuning, Torturous racing conditions, Avoid problems due to extremes of temperature
Low-speed performance

What to look for when choosing a racing plug

Shell desigh – To determine what kind of shell design fits in your engine, check the serial number of regulation plugs or the plugs you are currently using to verify the thread diameter, pitch, thread length and shell seat.
Firing End design – Refer to the section below on electrode design to determine which type is best for your needs.
Heat range – It’s important to choose a racing plug with a heat range that keeps the electrode at an optimum temperature under even the most torturous racing conditions. And remember : A higher heat-range number does not improve engine performance, it increases the plug’s ability to dissipate heat.
Resistors – Due to advances in ignition-system technology, there is little if any difference in performance between plugs with resistors and those without. However there are still some variations of some models that require plugs with resistors to avoid engine trouble.

Choosing a firing end design

Although a good rule of thumb is that the more an electrode projects into the cylinder, the better ignition it provides, it’s also true that longer projections are more susceptible to the wear and tear of extreme temperatures. High-power, high-performance engines, of course, not only run hotter, thex also vibrate more, which is why we recommend choosing a firinig end design that reduces exposure of the electrode and insulator as much as possible.
Once you’ve found a plug that matches your needs, give it a try and feel the exhilaration of getting 120% performance from your engine.

Projected type

Quite similar to a standard spark plug electrode, these plugs give good overall performance in lightly tuned and naturally aspirated engines, as well as good performance in the low to medium turque range in turbo engines.

Angled ground strap type

These provide superior performance in turbocharged engines with power boosts of 50% or more. The short ground electrode is also highly durable against mechanical shock.

Semi-surface discharge

In a sense, this is the ultimate plug configuration. Nearly all insulator cracking and electrode melting can be prevented with this type.
Nevertheless, service life and low-speed performance may suffer slightly.