Tentenths

Not sure if these have been covered before, but I was intrigued by the concept.

Extract from their website [http://www.prepsparkplugs.com/frames.htm]

"...Not all engines are alike, and likewise, not all cylinders within an engine are alike. Detonation may appear in only one or two cylinders, while the others do not detonate. Unlike oxygen sensors and some knock sensors (which can only retard ignition timing for all cylinders equally), PREP Spark Plugs act on a cylinder-by-cylinder basis. If detonation only occurs in one cylinder, then only one PREP Spark Plug will vent. This makes identification of the detonating cylinder(s) an easy task.

PREP Spark Plugs offers something no other spark plug can provide: Increased Performance Potential. New spark plugs will, almost invariably, provide better engine performance; this is the basis of claims of the "high performance" spark plugs. Actually, any new spark plug will do the same as the new "high performance" ones do. But PREP Spark Plugs provide something no other spark can offer. With PREP Spark Plugs installed, an engine tuner is free to experiment with power adding modifications such as Nitrous Oxide, more boost, more advanced ignition timing, and leaner mixtures. All of these lead to greater power generation, but carry the risk of engine damage from detonation. PREP Spark Plugs provide Increased Performance Potential because the tuner may "dial in" more power, knowing that his risk is a set of spark plugs, not a set of pistons. Consider the ease of installation of each of these.

PREP Spark Plugs are easy and inexpensive to install, unlike the addition or modification of knock or oxygen sensors. High performance "chips" and programmable engine control systems are available… at a price. And the cost of tuning a high performance engine can be the cost of the engine. It has been said a thousand different times and a thousand different ways: Detonation Will Destroy Your Engine. Installation of PREP Spark Plugs is the cheapest, simplest and easiest to install method to prevent detonation..."

To a self confessed "non techie" their claims sound fairly plausible, but I've been taken in before! What do others think (esp. the tuners)?

Gidney&Knowlesy

The Subaru ECU can already tell if there is a misfire in the cylinder & which cylinder has misfired.....so no need for a "prep" plug. Good marketing idea, though not necessary for a Scoob & I should imagine many other cars out there!