I think this thread is now active. I did some research on spark plugs; and found that the Platinum & Iridium Plugs are made especially for performance engines i.e. turbo/super charged. Theres no doubt they would add to performance of regular efi engines but at some cost.
So why not get the most of our money by using economical option.
This is what Bosch has to say;
"Your engine's new performance-enhancer: the high-power spark plug for retrofitting. Another innovative idea from Bosch. The Bosch Super 4 operates on the state-of-the-art air-cushion-spark principle and is the first spark plug to feature four thin ground electrodes with one pointed, silver-plated center electrode. This combination is unique in the world and has decisive benefits. The ignition spark always chooses the best path for reliable ignition according to the engine load. Technical superiority - now available for your car. The Bosch Super 4 does more than a conventional spark plug. In all situations, throughout its service life. The advantages: * Noticeable improvement in acceleration * Significantly improved engine smoothness * Superior engine versatility * Electrode gap adjusted ex factory"
I took this from automedia regarding Platnium vs Iridum spark plugs;
Kenny Duttweiler of Duttweiler Performance in Saticoy, California is no stranger to making horsepower, especially with turbochargers. After years of building little turbocharged V-6 Buicks that produce in excess of 1,500-hp, he found a lucrative market in NMCA's "World Fastest Street Car" classes building 1,700-hp small-block Chevy V-8s for winning racers such as Bob Rieger and Rod Saboury.
So when he bolted a customer's NHRA AA/Altered Turbo Ford engine on the dyno and had problems making the requisite 1,950-hp (out of 450 cubic inches on gasoline), he left no stone unturned. The engine had state-of-the-art everything—Motech engine management system, MSD Digital 7 ignition system and everything else you could think of. Kenny had isolated the problem to inadequate ignition performance. There was no audible misfire, but the engine made 1,700-hp at 17-psi of turbo boost and only 1,100-hp at 24-psi, indicating that the increased cylinder pressure was causing an undetected intermittent misfire. Reasoning that it was an engine-management or ignition-system problem, he replaced both. However, his Stuska dyno yielded the same results. Kenny replaced spark plugs several times with the best racing and platinum plugs he could find; still no improvement.
Kenny had correctly diagnosed the problem, but as far as he knew, there was no solution. He was already using the most powerful engine management and ignition systems on the planet, and he'd tried most of the "state of the art" spark plugs on the market. Kenny was running out of options and stated prophetically, "Some engines are spark-plug sensitive, especially Hemi-style engines. That's why Chrysler designed dual-plug cylinder heads for their Pro Stock motors in the early '70s. A turbocharged race engine is a variable-compression engine. At 25-30 psi of boost, the cylinder reaches an incredible 2,800-3,000 psi. The higher the cylinder pressure, the harder it is to fire the spark plug. This Ford engine we're developing is the worst of all circumstances. It has a hemispherical-shaped combustion chamber and a 4.670 cylinder bore that is a large area to light off at high rpm."
Kenny had no idea that the solution to this perplexing problem would be a new iridium spark plug technology from Denso. In Denso's research for an OEM spark plug that would provide 200,000 miles of service life and lower vehicle emissions, Denso developed a new iridium alloy electrode spark plug. The progression from nickel alloy plugs to platinum plugs in 1982 was a giant leap forward in technology. Denso's introduction of the iridium alloy spark plug will prove to be even more significant, especially for high-performance and race engines. The major difference in the Denso Iridium Power spark plug and conventional platinum plugs, besides the alloy, is the size of the center electrode. A typical platinum plug has a 1.1mm diameter center electrode. The Denso Iridium Power OEM plugs have a .7mm diameter center electrode and the Denso high-performance plugs have a .4mm center electrode.
What does size have to do with it? Less voltage is required for a smaller center electrode and results in better ignitability. The smaller the electrode, the more centralized the electrical potential is around the electrode tip. The required voltage can be reduced because the level of the electric field is made stronger and local insulation (air gap and electrode surface oxidation) breaks down more easily. The bottom line is that it takes approximately 5,000 volts less to fire a Denso Iridium Power spark plug versus a conventional platinum spark plug.
So why not just make a smaller diameter electrode spark plug out of platinum? It just wouldn't last. The small-diameter center electrode reaches much higher temperatures. Iridium's melting point is 700 degrees C higher than platinum, and laboratory tests have shown that with the same-size electrode iridium, plugs were four to five times as resistant to wear as platinum. Much of Denso's R&D went into finding the perfect iridium alloy (90% iridium, 10% rhodium) that would provide 200,000 miles of service, and working out the manufacturing process to "draw" the electrode into the extremely small .4mm-diameter wire.
Kenny was contacted by a Denso representative to test a set of Denso Iridium Power high-performance spark plugs under extreme, real-world conditions. So he installed the plugs and ran the turbo boost all the way up to the 40 psi limit. The dyno numbers tell the story: 1,850 repeatable horsepower, test after test. Kenny admits he's still shy 100-hp from the goal of 1,950-hp, but a camshaft change is in the works to make up the deficit.
So what does this mean to the average performance enthusiast? If you are running any engine with high cylinder pressures generated by high-compression pistons, nitrous oxide, superchargers or turbochargers, you may be having intermittent misfiring and not realize it. Of if you have less than the latest, greatest ignition system, you can essentially gain another 5,000 volts of ignition performance by just changing your spark plugs to Denso Iridium Power!
/dtdtThis is another article worth reading;/dtdt
For lots more info on NGK spark plugs, check out NGKs FAQs.
] I have heard that platinum plugs aren't very good for performance...how is this so?
All things being equal, a more powerful spark will create higher cylinder pressure which will create more power. The power of a spark is determined by its voltage (more voltage=more powerful spark).
Aside from variables such as cylinder pressure and A/F ratio, the amount of voltage required to jump across the gap of a given type of spark plug is determined by the plug gap. A smaller plug gap requires less voltage to jump across the gap and a larger plug gap requires more voltage to jump across the gap.
There is a way to reduce the amount of voltage required to jump across the gap of a plug. By increasing the number of sharp edges that the spark can jump from and to (as in SplitFire and Torquemaster plugs) or by using an electrode material that is a more efficient conductor than the standard steel material (like platinum) you can decrease the amount of voltage required to "jump the gap". The only problem is that these "specialty" plugs will produce a less powerful spark than a standard plug will at the same gap. This means that, as long as your ignition system can provide enough voltage to jump the gap on the spark plug all of the time, with these "specialty" plugs installed in your car your engine will produce less power than it will with standard spark plugs. The only way you can regain the power lost with these "specialty" plugs is to open their gap out farther (a wider gap requires more voltage to jump the gap).
I've seen a number of cases where people have installed SplitFire, Torquemaster or platinum plugs in their car in the place of standard spark plugs and have complained of reduced power. In all of these cases the specialty plugs were installed using the plug gap specified for the car's original standard plugs (with the exception of the Torquemaster, whose gap is not adjustable). The reduced spark power due to the reduced voltage requirement of these plugs was the culprit.
Ok guys what do you say.