tntsuperjet
Tntperformance-engineering.com
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I got a few PM regarding this so I will try to explain.
The BR8ES or the ES LINE of sparks plugs is designed for air cooled generators and motorcycles.
These plugs are not designed for high comp water cooled applications.
They require a lot of spark energy to fire at high rpm's as they where designed for low rpm engine.
There basically a generic plug.
Now watercraft industry has saturated itself with this line of plugs 6-7-8- and very few running 9 heat range.
The Es fouls quickly and easy in water cooled head because of its thin perimeter design and inset electrode.
Now you all running decent size bores 83mm or bigger, have weak plug in a engine that taxes the stock ignition do to higher Cyl pressures then stock. Yes more compression means more spark energy needed to bridge the plug gap.
So you need a spark plug that will help keep build up from fouling, proper heat range for your gas and compression, proper gap for your ignition and compression ratio.
Stock ignition coil is only capable of firing a .0010 or ten thousands gap at 8000 rpm at 200psi compression. The internals of the ignition coil and stator could begin to break down if the spark plug gap requires more spark energy to gap then to arc jump internally.
To give a better perspective a 3/4 in spark gap at 5,000 ft elevation takes 18k volts to bridge the gap. At sea level that same gap requires 20k volts. At 150psi pressure it takes 60k volts ( Rough estimate)
So as your compression goes up you increase the density of air and higher density requires more spark energy to penetrate through open space.
So stock ignition on a 62t ignition running 200psi comp is only capable of .0010-.0012 plug gap.
Yes that's ten to twelve thousands of an inch.
Now you need a spark plug that has semi exposed electrode isolater to allow for burn off of heavy deposits, thick outer containment area to avoid flash heating.
How to find a spark plug that is best for your engine??
your engine builder should have a plug that was designed for your engine.
But if you at a loss for a plug try ngk BR9EYA.
That plug was designed for large bore water cooled two stroke.
Do not run it at over .0020 gap with stock ignition.
Rule of thumb
100 psi comp .0032 gap.
-.00011 gap for every 10psi over 100psi comp.
min gap is .0010-.0012
The BR8ES or the ES LINE of sparks plugs is designed for air cooled generators and motorcycles.
These plugs are not designed for high comp water cooled applications.
They require a lot of spark energy to fire at high rpm's as they where designed for low rpm engine.
There basically a generic plug.
Now watercraft industry has saturated itself with this line of plugs 6-7-8- and very few running 9 heat range.
The Es fouls quickly and easy in water cooled head because of its thin perimeter design and inset electrode.
Now you all running decent size bores 83mm or bigger, have weak plug in a engine that taxes the stock ignition do to higher Cyl pressures then stock. Yes more compression means more spark energy needed to bridge the plug gap.
So you need a spark plug that will help keep build up from fouling, proper heat range for your gas and compression, proper gap for your ignition and compression ratio.
Stock ignition coil is only capable of firing a .0010 or ten thousands gap at 8000 rpm at 200psi compression. The internals of the ignition coil and stator could begin to break down if the spark plug gap requires more spark energy to gap then to arc jump internally.
To give a better perspective a 3/4 in spark gap at 5,000 ft elevation takes 18k volts to bridge the gap. At sea level that same gap requires 20k volts. At 150psi pressure it takes 60k volts ( Rough estimate)
So as your compression goes up you increase the density of air and higher density requires more spark energy to penetrate through open space.
So stock ignition on a 62t ignition running 200psi comp is only capable of .0010-.0012 plug gap.
Yes that's ten to twelve thousands of an inch.
Now you need a spark plug that has semi exposed electrode isolater to allow for burn off of heavy deposits, thick outer containment area to avoid flash heating.
How to find a spark plug that is best for your engine??
your engine builder should have a plug that was designed for your engine.
But if you at a loss for a plug try ngk BR9EYA.
That plug was designed for large bore water cooled two stroke.
Do not run it at over .0020 gap with stock ignition.
Rule of thumb
100 psi comp .0032 gap.
-.00011 gap for every 10psi over 100psi comp.
min gap is .0010-.0012
