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Spark plug gap dilema.. 1.1mm or 0.8mm

Remix-

By Remix-,
in General Maintenance

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89CAL
89CAL

Stock ECU? Buy proper ECU

iruvyouskyrine
iruvyouskyrine

i heard a rumor that haltech sell haltech ECU's. Maybe ring them to confirm.

gtrken
gtrken

Got to agree with Duncan. The bigger the gap , the better the spark. The coil has to build up a stronger spark to jump the larger gap which makes for a fatter , hotter spark. Downside is that too mu

WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted
Gap them to 0.8 and you should feel a little extra in performance as well even on stock boost.

what proof do you have of this? i find that very hard to believe...

if it wasn't missing on stock boost with 1.1mm then don't change it! i now run 1.1mm gap with 12psi of boost on my rb20 and have no issues at all. maybe its an rb25 thing?

Guest Robo's

Guest Robo's

Posted
Posted

The closer the gap the stronger the spark, simple really, but there is a point of where you go backwards. I saw a Zoom article of some dyno testing of spark plug gaps too and 0.8 came up with the best.

Well your lucky of getting no missing issues with 1.1 gap.

hako Enthusiast

hako

Posted
Posted
So a RB20det running 20psi with 1.1 or 1.2mm gap miss-fire?

in most cases, yes.

depends on a few factors, but as mentioned the increased pressure would decrease the ability of the spark to arc across the gap.

might have no such problems with aftermarket coils, but it doesnt take much work to close the gap a little.

Duncan Grand Master

Duncan

Posted
Posted

hang on. unless it is missfiring you want the biggest gap you can, it provides a more ven burn.

ppl have to move to lower gaps because their spark is not strong enough, not because it is better

gtrken Grand Master

gtrken

Posted
Posted

Got to agree with Duncan.

The bigger the gap , the better the spark. The coil has to build up a stronger spark to jump the larger gap which makes for a fatter , hotter spark.

Downside is that too much compression/boost will blow the spark out or not allow it to jump the gap.

Whoever said that the closer the gap , the better the spark has not done 1st year apprentice mechanics :P

Which is why with CDI type systems you can run a much greater spark gap as they pack a mean punch. Grab an Autronics CDI equipped spark plug as opposed to a normal coil and see what I mean.My hand was numb for about 1/2 hr. One of our race engines lost an electrode hook on the dyno and it was still firing with a CDI system.

Cheers

Ken

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WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted
Got to agree with Duncan.

The bigger the gap , the better the spark. The coil has to build up a stronger spark to jump the larger gap which makes for a fatter , hotter spark.

Downside is that too much compression/boost will blow the spark out or not allow it to jump the gap.

Whoever said that the closer the gap , the better the spark has not done 1st year apprentice mechanics :P  

Which is why with CDI type systems you can run a much greater spark gap as they pack a mean punch. Grab an Autronics CDI equipped spark plug  as opposed to a normal coil and see what I mean.My hand was numb for about 1/2 hr. One of our race engines lost an electrode hook on the dyno and it was still firing with a CDI system.

Cheers

Ken

about time someone with sense jumped in here!

it seems that too many people read something on these forums and then become armchair tuners...

if you're not missing on a 1.1mm gap then don't re-gap to 0.8mm. If 0.8mm were better then i'm sure all plugs would be gapped to 0.8mm. if smaller gaps were better then wouldn't all plugs be running gaps in micrometres? its logical really...

funkymonkey Grand Master

funkymonkey

Posted
Posted

rather than decreasing the gap in your spark, it'd be wiser to increase the power of the spark innit? wire up a set of quick charge capacitors to your sparks and bob's yer uncle...

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