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why stop at 1.5mm. (spark plugs)

whiteknight
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turbohectics Proficient

turbohectics

Posted
Posted
just bought and fitted a set of split fire coils and planning to regap spark plugs. im want to gap them at 1.1 but am thinking why stop there? why not 1.5 or more?

I doubt they could run a spark that hectic ,I just recieved mine yesterday yet to install let us now what gap you can run b4 it breaks up (can't be bothered gapping the plugs so just gonna buy 1.1mm )

RB30-POWER Mentor

RB30-POWER

Posted
Posted

although the splitfire coils may be an improvement over standard coils it will never have the power of a CDI system that can run big gaps under high cylinder pressures.

let us know how you go though, doubt it will do 1.5mm gap myself.

MANWHOR3 Proficient

MANWHOR3

Posted
Posted

That sounds like an interesting idea. I'm running a set of stock coils in my car atm, and they are in very good condition. I run a 1.1mm gap no problems at 10psi.

Perhaps if the splitfires are better, you might be able to run a bigger gap. Only one way to find out. Try it.

turbohectics Proficient

turbohectics

Posted
Posted
And the point of this being what?

:confused: :confused: :confused: :chairshot :chairshot

More efficient combustion ,more fuel burnt equals more power

I found this article on a site ....We haven't seen any benefits of gaps beyond 0.045-inch, so that should be the outer limit of sparkplug gap. Don't re-gap sparkplugs too many times because the ground strap metal will fatigue and may break. If your engine makes more than 75 horsepower per cylinder, gap the plugs only once. If your engine makes more than 100 horsepower per cylinder and/or sees extended periods of high RPM and/or high boost, we'd have to say don't gap the sparkplugs at all! (Here, it pays to use high-quality plugs that have a consistent gap as-manufactured.)

Robo's Mentor

Robo's

Posted
Posted

I done this little exercise as i have splitfire coils. Gapped at 1.1mm and running 20psi, it missed. Gapped them down to .95 and it still missed. Just above .8 i gapped them at and now i have no miss. Remember im running alot more boost though.

blind_elk Grand Master

blind_elk

Posted
Posted

There might be something about this on the NGK website. And I recall someone (Zoom! or Autospeed) did this comparison a while ago.

You need to have a coil that can generate enough energy to jump the plug gap. Even if if can, it may be so borderline in strength that it actually causes a worse burn than the narrower gap could produce. This is often why you need to gap down at higher boost levels - the poor spark is more susceptible to the higher cylinder pressures that come with increased boost.

There's a lot of physics and chemistry involved - it's not just a simple matter of saying that a bigger gap will produce a better burn.

sproosy Grand Master

sproosy

Posted
Posted
:confused:  :confused:  :confused:  :chairshot  :chairshot  

More efficient combustion ,more fuel burnt equals more power

I found this article on a site ....We haven't seen any benefits of gaps beyond 0.045-inch, so that should be the outer limit of sparkplug gap. Don't re-gap sparkplugs too many times because the ground strap metal will fatigue and may break. If your engine makes more than 75 horsepower per cylinder, gap the plugs only once. If your engine makes more than 100 horsepower per cylinder and/or sees extended periods of high RPM and/or high boost, we'd have to say don't gap the sparkplugs at all! (Here, it pays to use high-quality plugs that have a consistent gap as-manufactured.)

sorry to say this: but dave got :Owned:

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