I saw something on the tube last night about a new type of plug configuration that doesn't have part of the electrode blocking the spark from the combustion gasses. They said it was called a halo plug and they've been using it in Europe for a while now. Has anybody seen these or had any experience with them? Supposedly they are more effectient. I am really no inclined to believe things I hear on TV and I think the guy talking about them might have been an environmentalist wacko. And since the enviro crazies usually design things that cost more and don't work as well I fiugred I'd probe the minds of thirdgen. I think there may have been a post on this a while back put I can't remeber.
bsa

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"If they do not run, Then they will die." - Stonewall Jackson
#3
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BSA,

There are a few things to understand about automotive engineering. If there is a technology in existence that will increase power and reduce emissions, and increase fuel efficiency, and is as inexpensive as a set of spark plug, every new car would have them. Ford would steal the idea from the designer, GM would steall the idea from Ford, Daimler would steal the idea from Saab, etc. The ricers would finally steal the idea from whoever they could, and every car would have open-front spark plugs. In addition to that, every plug manufacturer would market the plugs to the aftermarket. Their claim that the plugs have been in use in Europe is not an exaggeration. They have been in use in the U.S. for almost forty years.

If you really want to try open-front spark plugs in your engine, save the shipping and handling charges and go to the parts store to get a set of marine plugs. They really don't do any better or worse than the conventional plug designs in a two-stroke marine engine. They seem to run poorly in a SBC because the flame kernel is too remote to promote a good start to cimbustion. The reason automotive plugs have an extended tip is to present the spark farther in the chamber to produce a faster ignition of the fuel/sir mix, which is a good thing. Marine engines would do the same thing if they could, but the chambers are generally so tight that there is no room for an extended nose plug.

As far as the electrode blocking the spark from the fuel/air charge, that is an unsupported argument that appears to have a sound basis to those who have no understanding of combustion dymanics in an IC engine. It LOOKS reasonable to those who don't have a clue, so they sell spark plugs. They'll get lots of testimonials from people who have used them saying how much better they are, but will have no empirical data to support their claims, like dyno graphs. These are the same people who "feel" like their cars run better after an oil change. It's all a perception and no science.

If you are really curious, get a set and try it. After a week or two, let us know how much "better" you car runs, but give us dyno graphs instead of opinions.

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Later,
Vader
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"Fear is how I fall, Confusing what is real..."
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Vader, what about the claim TPIS makes that they gained 8 HP on the dyno by just changing to Bosch +4's? That is pretty cheap money to come up with 8 HP. And I don't know what TPIS would have to gain by helping Bosch sell plugs. Bosch probably doesn't even know they exist. The old trick of indexing plugs has been around for a long time, and as far as I see it that is precisely what the +4 plug does. It changes an axial spark to a radial spark and eliminates the shielding effect. You have to be careful about HP claims by aftermarket companies, but I think this is legit.

 

Iroc Louver, stop for one second and think of what direction a spark plug faces in a SBC combustion chamber. The plug threads in nearly perpendicular to the direction of piston travel. The +4 is not indexed, in fact, one (or a combination of 2) of the electrodes will ALWAYS be in the way of the compressing mixture/flame front.
In a DOHC engine, or any engine with a plug that threads in the top , parallel to the piston stroke (chrysler hemi for one) then i agree the +4 is perfectly 'indexed'. But in an engine design such as ours, you index a plug by putting the electrode on the far side from the exhaust valve with the spark also open to the direction of piston travel. No matter how you turn a +4 the best you'll have is a window between 2 electrodes that opens facing down, which is nowhere near as effective as the completely open side of a conventional plug. Your 'radial spark' is at best partially shielded, at worst completely shielded from the compressing mixture. While a conventional 'axial spark' always has at worst a partially shielded path from the compressing mixture, and that is if it is indexed with the electrode facing straight down. If it is even a fraction of a turn from straight down then the spark wil be going straight across an open path with the upcoming mixture.
...ed

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Ed Maher - Moderator @ The Carb Board
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Ed, I'd have to say you are right. I didn't think about the orientation in a SBC, but your explanation makes sense. I guess I am more confused now about the TPIS claim though. Maybe just another case of horse puckey.

 

Just another company claiming things to make money, but not showning the proof.