Specifications

HotWires

show an increase of

8 horsepower on this

Small Block Chevy

RPM StockWires HotWires IncreaseHP

4500 305.7 308.3 2.6

5000 337.9 342.4 4.5

5500 351.4 359.2 7.8

5750 350.5 358.6 8.1

A Better Spark Plug

Spark plugs are the subject of much controversy. In comparison to internal combustion engines and

their management systems, spark plug design has hardly been improved. Malfunctions still occur, but

they are not as noticeable anymore mainly because of improved ambient conditions. At least one of

the three most important spark plug properties has to be sacrificed in order to increase or emphasize

one of these characteristics: efficiency, durability and heatrange.

For high performance or racing applications, an efficient spark plug is needed. Such a spark plug operates

optimally only within a narrow heatrange without any consideration for durability. This is not a good

spark plug for everyday street use, as a wide heatrange is essential to assure good drive- ability under all

temperature conditions. Heatrange latitude of standard low-cost spark plugs for passenger cars has

improved, but with major trade-offs. They are designed to offer a wide heatrange only, without any

consideration for efficiency. The ignition system has to compensate for low spark plug efficiency and

wide spark plug gap caused by wear. Original equipment spark plugs offer a wide heatrange and high

durability to increase spark plug change intervals. These are the least efficient spark plugs. In order to

reduce wear, erosion resistant materials and suppressor resistors are used which considerably sacrifices

spark plug efficiency. The correct relationship between efficiency, durability and heatrange is important

and has to be considered over the entire life of the spark plug. A functional combination of these

properties is possible and is only a matter of technology and materials used.

When reading spark plug advertisements one can get the impression that small diameter center electrodes,

uniquely shaped electrodes or built-in resistors are best. Think again!

A Resistor is exactly what the word implies. When the spark crosses the point of resistance, much of

the spark energy is lost. A resistor is like an electronic

obstacle and could be the cause for a weak spark.

Due to manufacturing tolerances and lack of quality

control, even non-resistor spark plugs often have a

resistance of 10, 100 or even 1000 ohm. Always

check spark plugs for resistance before use. Using

spark plugs that have resistance due to manufacturing

tolerances, internal damage or by design will weaken

the spark, which could result in lost horsepower and

poor fuel efficiency.

Horsepower Test on Superflow Dyno