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#1
10-11-2003, 09:22 AM
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muscle car data
Folks,
I follow the Mustang / 5.0 stuff a bit. Many folks there use enhanced coils to boost the spark. Some magazine tests have shown a 5-10 hp gain on a 300 hp engine. All to the same point as above - more / better spark can ignite better, although I do believe most recent cars have pretty optimized systems. Chuck 
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#2
10-11-2003, 11:22 AM
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Most of such results are urban legend.
If there were significant efficiency improvement to be gained with spark plugs do you think the manufacturers would spend the billions they do on emissions/engine technology. I doubt it.
__________________
Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician
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#3
10-11-2003, 11:50 AM
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Modern emission controlled cars have very powerful ignition systems. They have to in order to reduce misfires to a minimum to pass emission certification tests.
Many aftermarket vendors advertise large voltages, but these are meaningless. The actual voltage required for a spark to bridge the plug gap is rarely more the 10-12 kilovolts. The real measure of ignition system performance is per spark energy and spark duration. Energy is usually measured in "millijoules", but it's rarely specified. CD ignitions are popular, but they are poor choices and never used by OEMs. Street engines need long duration sparks to ignite low density, lean, and exhaust gas diluted mixtures. Inductive systems provide the long duration necessary. One well known CD ignition manufacturer hypes their multiple sparks at low engine speeds. Well, multiple sparks are necessary to avoid excessive misfiring, but the second and third sparks arrive considerably after the proper timing point. Duke
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#4
10-11-2003, 05:37 PM
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sorry - wrong place
Folks,
Oops, I meant to put this as a reply in the lexus cutting spark plug topics..sorry. Mod feel free to move. The car mag I read was testing about a '90 Ford 5.0 V8. They tested before and after on a dyno (swapping in the aftermarket coil). Small net result in HP for an engine in the 300HP range - 75 or so above stock. So it was probably fine for stock and had a small inefficiency for the increased fuel flow. Chuck
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#5
10-11-2003, 07:24 PM
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MB Autowerks' Kleeman installation in a CLK320 took it from 164whp to 275whp. I don't recall any ignition mods.
Mitsubishi turbo folks will take an Eclipse from 150whp to 300whp without touching the factory coil (in many cases without even pulling the head). That's going from 14psi and pump gas to 20psi and race gas - not exactly the ideal conditions for spark to jump a gap. Sixto 95 S420 91 300SE 87 300SDL 83 300SD Last edited by sixto; 10-11-2003 at 09:58 PM.
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#6
10-11-2003, 08:15 PM
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All a spark does is start the ignition of the fuel-air mixture. If the mixture is lit off, the ignition system has done its job. No need for anything fancy. If there is measurable gain in performance (HP, idle, economy, etc.) with an enhanced system, that means the original ignition system either wasn't doing it's job or something is out of tune and the enhanced system has masked the shortcomings.... kinda like using premium fuel in a regular burning car to mask spark knock.
__________________
95 E320 Cabriolet, 159K
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