The SplitFire spark plug is a spark plug featuring a split ground electrode. SplitFire claims that this "V" electrode design allows more complete combustion by allowing the ignited flame to pass through the gap in the electrode, instead of around the electrode.
SplitFire spark plugs were popular and heavily advertised in the early 1990s despite controversy over their effectiveness. The manufacturer also sponsored the SplitFire Spark Plug 500 NASCAR stock car race. In 1997, the United States Federal Trade Commission charged SplitFire with deceptive advertising. The manufacturer settled the charges with the FTC; as part of the settlement, SplitFire was prohibited from making deceptive claims about fuel economy or emissions. After the settlement, the popularity of SplitFire's spark plug range declined, but many drivers continue to use the product. The company still exists today, and its range of products has been expanded to include plug leads, dials and gauges, DIS coil packs and several other products in this area of the performance market.