Fuel economy and spark plug gaps

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vlad01
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Re: Fuel economy and spark plug gaps

Post by vlad01 »

Dylan wrote:I had that with bosch once. I ran there's in a V8. For example NGK heat 6 was BOSCH heat 7 i think. One of the big manufacturers has a comparison chart.
I ran the Bosch super 4's in a 5 litre and they were fantastic. That engine used to kill a normal set in 1 tank it was that badly tuned. I got a long time out of the 4's.
Way before i knew about tuning, and that was after a pro dyno tuned it. Idle must of been aroun 10:1 AFR.

I had bosch super 4 in my v6 once. didn't go so good. used more fuel and idled rough.

I still have them sitting on a shelf with less than 10k on them.
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Holden202T
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Re: Fuel economy and spark plug gaps

Post by Holden202T »

I had to use Bosch plugs once as thats all I could get on a Sunday arvo!! Ran like shit, missed at full noise and backfired ... As soon as I could I got ngks and back to happy!!

Not sure how they differed but it sure made a difference!
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delcowizzid
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Re: Fuel economy and spark plug gaps

Post by delcowizzid »

video of whats going on inside there
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Gareth
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Re: Fuel economy and spark plug gaps

Post by Gareth »

I've heard of 'little men with hammers' inside an engine, but men with cameras?... :D
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Holden202T
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Re: Fuel economy and spark plug gaps

Post by Holden202T »

thats a cool video :) take notice also of how far the valve moves before it really starts to flow some air/fuel into the cylinder!
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Re: Fuel economy and spark plug gaps

Post by slewinson »

And also the flame distribution and propagation that hovers near the inlet valve.

Simon
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Re: Fuel economy and spark plug gaps

Post by brindo »

Slightly off topic, but many years ago I vaguely remember reading an old engine manual regarding ignition system polarity. If the polarity was wrong, the spark plug would wear the centre electrode out very quickly. It described a test using a lead pencil that was put in place between the HT lead and the spark plug and looking at where the spark was jumping, either between the lead and the pencil or the pencil and the plug.
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Re: Fuel economy and spark plug gaps

Post by vlad01 »

slewinson wrote:And also the flame distribution and propagation that hovers near the inlet valve.

Simon

yeah its interesting but these videos are made using a stroboscope type imagery system so each frame is a completely different cycle hence why its all over the shop. but it does show an "average" scenario as a collection of images.
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Re: Fuel economy and spark plug gaps

Post by slewinson »

brindo wrote:Slightly off topic, but many years ago I vaguely remember reading an old engine manual regarding ignition system polarity. If the polarity was wrong, the spark plug would wear the centre electrode out very quickly. It described a test using a lead pencil that was put in place between the HT lead and the spark plug and looking at where the spark was jumping, either between the lead and the pencil or the pencil and the plug.
Yep. On aircraft you swap plugs between alternate firing spots because the magneto goes positive and negative alternately, ending up with uneven plug wear. The same will tend to happen with the contemporary wasted spark systems that use double ended coils. One end will wear the center electrode and the other the ground.

Simon
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The1
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Re: Fuel economy and spark plug gaps

Post by The1 »

well ive found no difference in MAF read figures or fuel usage with 0.8mm plug gap, the plugs also look the same. Though i havn't had a real stinkn hot day yet to see if helps spark.
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