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shacar87 · 11-17-2003, 12:26 PM

silverSN95,
I read a tech article on this in my Muscle Mustang and Fast Fords magazine. They took stock heat range plugs, and ground the prong that arches over the center electrode so the end of it was round (like a horseshoe), not square, and the end of it should extend to right in the middle of the center electrode, not over to the far side like stock.

When comparing dyno charts of before and after, with no other changes to the engine, the cut plugs netted a 20 ft/lb increase in torque just off idle! Now that 20ft/lb gradually dropped as the RPMs went up, but with NO loss of torque anywhere in the powerband when compared with the stock plug numbers. All it did was slowly dropped until about 5500 RPM, where it just matched (but never fell below) the stock plugs numbers till they stopped at 6500 RPM. And horsepower was up about 1-3 horses the whole way from start to finish!

They said about it having to do with low RPM swirl in the combustion chambers ( I don't remember exactly how they put it), that changes as the RPMs rise, and that's why the numbers drop also. They said the main factor in all this is that the cut makes the plug fire cooler, which reacts better with the low swirl.

Well, I was curious about all this, so I snooped around at the local drag strip. I found out that alot of racers do this to their plugs for that little extra! And that was everything form stockers to 10sec. rides. So I went home and tried this, next time I raced, I honestly could feel my car launching a bit harder, and it was backed up by a slight drop in my 60ft. times. Now I do this to all my rides, even my VERY lightly modified 91 Escort GT (which by the way hasn't been beat by ANY 4-banger without a turbo or nitrous yet)! If you look at the majority of the newest performance plugs on the market, they usually have a rounded or narrowed prong (the Rapidfires), or smaller electrode. Now it may be diiferent for certain setups, like 7-9000RPM motors, that i'm not sure of, but for the majority of street/strip cars, it works. Try it and see for yourself. If you have any more questions about it, just post, and I will try to answer them the best I can. Good luck!

11-17-2003, 12:26 PM	#11
shacar87 Registered Member Join Date: Nov 2003 Posts: 10	silverSN95, I read a tech article on this in my Muscle Mustang and Fast Fords magazine. They took stock heat range plugs, and ground the prong that arches over the center electrode so the end of it was round (like a horseshoe), not square, and the end of it should extend to right in the middle of the center electrode, not over to the far side like stock. When comparing dyno charts of before and after, with no other changes to the engine, the cut plugs netted a 20 ft/lb increase in torque just off idle! Now that 20ft/lb gradually dropped as the RPMs went up, but with NO loss of torque anywhere in the powerband when compared with the stock plug numbers. All it did was slowly dropped until about 5500 RPM, where it just matched (but never fell below) the stock plugs numbers till they stopped at 6500 RPM. And horsepower was up about 1-3 horses the whole way from start to finish! They said about it having to do with low RPM swirl in the combustion chambers ( I don't remember exactly how they put it), that changes as the RPMs rise, and that's why the numbers drop also. They said the main factor in all this is that the cut makes the plug fire cooler, which reacts better with the low swirl. Well, I was curious about all this, so I snooped around at the local drag strip. I found out that alot of racers do this to their plugs for that little extra! And that was everything form stockers to 10sec. rides. So I went home and tried this, next time I raced, I honestly could feel my car launching a bit harder, and it was backed up by a slight drop in my 60ft. times. Now I do this to all my rides, even my VERY lightly modified 91 Escort GT (which by the way hasn't been beat by ANY 4-banger without a turbo or nitrous yet)! If you look at the majority of the newest performance plugs on the market, they usually have a rounded or narrowed prong (the Rapidfires), or smaller electrode. Now it may be diiferent for certain setups, like 7-9000RPM motors, that i'm not sure of, but for the majority of street/strip cars, it works. Try it and see for yourself. If you have any more questions about it, just post, and I will try to answer them the best I can. Good luck! __________________ Chevys are great!.........for lunch!!!