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Import Performance Cars, Builds, Installations, & Performance Car Repair Tips - Import Tuner Magazine
Fact Or Fiction - Sparkplug Horsepower
Will More Expensive Sparkplugs Increase Horsepower?
By Luke Munnell
This month we introduce a new department to 2NR: Fact or Fiction. Think of it as a blatant rip-off of MythBusters, but with a little Power Pages thrown in for legitimacy. Outrageous manufacturers' claims, long-debated tuning rumors and promises too good to be true will be put to the test once and for all, every month. Got an angle you'd like us to investigate? Drop a line to:
factorfiction@importtuner.com
This month we investigate a common question many "noob" enthusiasts have about "upgrading" OE-recommended sparkplugs to more expensive alternatives: Will it increase power? To find an answer, we hit Ultimate Tuning's Dynojet dyno, armed with some basic tools, our project DC2 and some popular sparkplug contenders.
Test 1: Champion Copper Plus. Costing you $1.49 each, these OEM-style copper plugs are about as basic as it gets. There was some debate as to whether or not they'd actually lose power over our two month old NGK coppers, but after three pulls they proved their worth, powering our B18B to a six-run average of 131.9 whp and 118.6 lb-ft of torque.
Test 2: Champion Platinum Power. While Champion makes no claims that these plugs will increase power, online outlets selling the product do. In theory, platinum is a more efficient conductor than copper and should improve combustion and increase power. When put to a six-run test, however, they brought an average power improvement of only 0.8 whp and 0.0 lb-ft of torque.
Test 3: Champion Iridium. Iridium is a favorite among many big-name aftermarket manufacturers, exotic car OEMs and enthusiasts looking for an extra edge. The center electrode of an iridium plug tapers to a point as it nears its ground; the idea being that it focuses spark energy into a narrow, more intense arc, thus increasing combustion efficiency. These plugs narrowly made it to the dyno at all-the first one we installed broke off in the cylinder head when we tightened it with the specified method of a half-turn past hand-tight. While the plugs' build quality didn't impress us much, they actually made some power on the dyno-2.9 whp and 1.1 lb-ft of torque over the coppers!
Conclusion: Swapping spark plugs can increase power output if the OE-recommended plugs can't ignite air and fuel at maximum efficiency. In modified engines-those with increased compression, forced induction, nitrous or water/alcohol injection-a substantial improvement can be seen through upgrading stock ignition system components. Engines like our N/A, stock-compression B18B do pretty well with the OE-recommended plugs, and frankly we were surprised to see any gains at all; a testament to the benefits of iridium plugs. While we don't agree with "big power" claims often promised by spark plug manufacturers, if they can do a better job of increasing combustion effi ciency, you'll see a few extra ponies and a slight increase in fuel economy. Our suggestion? If you're going to replace your plugs, spend a few extra $$ and buy iridium.
Next month: Fact or Fiction heats up as we test claims of a 25 hp increase from a "performance fuel treatment."
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