[Jim Ray]

Quote: Originally Posted by ScienceGuy (original)

Now we've moved on from
the actual claims on the website (about silver being better conductor) to NEW claims about the
spark being started farther into the cylinder. (Which is not claimed by the website)

Maybe you misunderstood how manufacturers change the center electrode length. They don't
make a shorter electrode by making a shorter plug, but by moving the point where the
electrode attaches to the main part of the plug. All plugs for a particular engine will have the
spark gap in approximately the same place in the combustion chamber. If they moved it farther
into the cylinder, the plug would hit the top of the piston.

It is typical for these claims of superiority to drift around to other characteristics when they get
challenged by engineering facts. We haven't gotten to magnet-vorticity yet, but I sense its
nearness.

Good to see you back ScienceGuy.

I think that the MINI claim for their optional plug wires is the most scientific and truthful.

"They are Blue".

[MINIMANIAUK]

Spark plugs in themselves do not constitute a performance upgrade,but they do have a lifespan (stock plugs are replaced at 50000 miles) and if the engine is modified for more boost pressure (read higher temps) then a plug that is rated for those higher temps is required and a revised gap required if boost is further increased,the cost of not replacing plugs can be very expensive(new engine)if the tip fails and falls off. in ignition terms the longest duration ,fattest spark is required for performance modified engines,for a stock engine -the stock ignition system is fine,but not a perfect design the placing of the coil on top of a hot engine not the finest of ideas,heat increases electrical resistance,a simple mod to the stock coil is to fit a small heatshield below it ,costs very little.
Ignition leads are simple devices but again can be improved its not the resistance of leads which is important its the insulation resistance which is paramount, with such high voltages across them ,the voltage will try to track across any lower resistance path the common points are at the joins to the plug boots at either end as it forms a place for moisture to sit , the insulator best suited to leads is silicon which also is flexible and heat resistant, but some leads are better than others in this respect as legally you can have a plastic mix with 20% silicon and sell them as "silicon leads" quality leads have much higher silicon content and last the life of the car. simply having larger output voltage from the coil is only part of the story as this alone does not increase the spark duration ,hence the various electronic devices available.
simply keeping the coil connection studs clean ,as they tend to corrode on the MINI is an easy task seldom done. Fitting new plugs,leads,and ignition units and boosters does however provide a "smoother " pulling engine and the system is ready for other power upgrades involving greater boost ,airflow and fuel flow,and a poor/ worn ignition system will use more fuel. also they look bling

[ScienceGuy]

I want to correct my misunderstanding of the spark-path I posted earlier.
(This is how science works. Study the problem some more and correct your misunderstandings.)

I knew in the back of my mind how coil-per-plug works, and "wasted-spark", but I wasn't
using all of my brain when I posted. So here's a correction.

The high-voltage (secondary) path doesn't go all the way back to the ECU and up the
coil primary ground wire as I stated. That's more of a coil-per-plug setup, and our cars
don't use a setup like that. Ours use what's called Wasted-spark where two sparkplugs
fire every time a spark is needed. One spark for the cylinder that is ready to go bang, and
one spark on a different cylinder that is on its exhaust cycle. This second one is "wasted".

Here's a schematic for a 6-cylinder ignition system which shows the setup:


So the path is even stranger than I posted earlier. There are TWO spark gaps, two internal-
to-the-plug resistors, and two plug wires with all that copper and connectors.

I was thinking about why in the heck people don't make a 4-coil setup for cars like ours.
Wouldn't you get a "stronger" spark if you eliminated the second "wasted" plug?
Wouldn't that be way way better than changing the last 0.2 Inches of center electrode material?

Well, as I learn, the resistance-to-spark goes way way up in a compressed-gas situation,
so the spark on the exhaust stroke jumps the relatively high resistance of the normal air
much easier than the spark on the compression stroke. This suggests that silver won't
make any difference at all.

Here's a very instructive web page about motorcycle ignition systems. (They do not
recommend nology wires and explain new coils are "cosmetic" enhancements.)
Daytona Twin Tec
Notice that they change ignition-system, camshaft, carb jets, intake and exhaust to get the
performance gains not just ignition parts.

Sorry for the misinformation, and happy to correct it.

[MINIMANIAUK]

The main reason for not having individual coil packs is cost,it would be relatively easy to convert to indivdual coil packs but each would be about £80 and then the ignition module would have to be added, the advantage with coil packs is the secondary coil to plug length is next to nothing and losses are minimal,reliability is increased as it is always the HT side that fails,but it costs more, another advantage is when the engine is 6/8/12 cylinder as a single coil will struggle at high rpms, but the MINI is only 4 cylinder and the present system is more than adequate for a stock engine. ignition systems do not create power,only allow air/boost/fuel to be increased,there is little point in having a multiple spark discharge or coil pack set up on a stock engine.