Nissan also built a bunch of dual plug engines. That was back when they even did it with a distributor. It was mostly for emissions, I thought. Almost all aircraft engines run dual plugs. They have large open combustion chambers and dual plugs helps pevent detonation and get the fire done sooner. Aircraft engines generally test pretty good for specific fuel consumption too considering the antiquated appearance of the combustion chamber designs.
Years ago Champion sold a plug with an auxiliary gap up in the ceramic insulator that allowed the ignition to build to a higher voltage before it fired. This plug should be compared with the old auxilary gap design and then tell us how much better it is. It just looks like too much for too little to me.
edit: I cannot find a description of the Champion plug on the net. Often times pulling the plug wire back from a fouled plug and having it arc to the plug would get the plug to fire.
Speaking of plugs, here is an Idaho invention that has run in quite a few engines, even airplanes. It appears derived from model air plane glow plug technology.
I saw an ad for those Pulstar plugs in Popular Mechanics (or maybe Popular Science). I'd view it with a healthy amount of skepticism. Like all these sorts of things the ad is carefully worded with highly selective facts. I'd find it more convincing if some truly independent labs had some positive results to report.
This reminds me of another magic spark plug company, back in the '90s. Their pitch was that spark plugs were not much more advanced than matches. And they were going to improve power and economy with precision sparking. They got some press, but then they vanished, and as far as I know without ever having produced a product.
at the claimed gains, you might as well start by side gapping and keying your current plugs. That might bring your mileage up enough!
i might go for the on top of the plugs type one, so that i can re use it with cheap spark plugs. My guess is that the spark comes immediately, with 100% rather than with like, 50% for a longer time.
i guess it could be condidered an ignition system change, since it is before the spark producing parts.
i will get the on top of the spark plug ones, some plugs, and see if it is really worth it. The plugs are not worth it to me, but since i only need one of the spark plug toppers, and a new plug, that might be worth it!
At 12,000 miles per year and $3.00/gallon, assuming I get a baseline of 30.0 mpg average, that's $1200/year for fuel.
If this device provides just 2% improvement, then my mpg would be 30.6 mpg, costing me $1176/year - a savings of $24 (8 gallons). So it would take just over 4 years to have these payback on the investment.
That seems like a rather long time for something with questionable benefit - which is going to hinge on the efficiency of the existing stock system. Of course if one drives further and will realize a greater FE improvement, they become more practical.
I would not rule out the benefit of these things however, as I have seen the improvement an MSD system can provide just to idle speed and quality. It's also reasonable to assume that auto makers might omit something like this due to the extra cost involved if it didn't bear out on a sales basis.
They probably do help. Anybody who's read more than a couple of threads here knows that every little bit eventually adds up to something significant, and even a 2% improvement adds to the bottom line.
Oh, and the plug-toppers are the smart money. Why would anyone want to throw out $25 plugs??
well my post didn't post or got lost in the electrons...so here it is again.
I have Pulstar plugs (friend working there, no I won't tell you who). Going from good plugs to them is like going from old worn out plugs to brand new ones. mild gains in idle quality and torque. I change stuff in my car all the time so it's hard to track FE of any one thing.
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
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