Spark plug gap dilema.. 1.1mm or 0.8mm

[Remix-]

Today i bought a set of NGK-R BCPR6ES -11 spark plugs that are gapped to 1.1mm. Is this ok to use? I have heard people saying that .8 gap is by far better... my car is not heavily modified and i am running stock boost....

[Guest RedLineGTR]

With stock boost it should be fine, i found that as soon as i ran anything more than stock on my 1.1mm gapped plugs then it started to missfire higher up in the rev range. My 2 cents

[steve_gts4]

i found my stock boost rb20 to run a little better with .8 gap plugs.

trial and error, i guess

[GTS-t VSPEC]

I would gap them down to 0.8mm:D I run 0.6mm on mine cause of the higher boost.

[Guest Robo's]

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

[WazR32GTSt]

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]

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.

[Remix-]

I think i might go swap them for 0.8's

[GTS-t VSPEC]

gtst89, You can just gap the 1.1mm ones down if you want, but getting the 0.8mm gap is a better option.

I agree with Robo, the gap does make a difference to the power delivery.

[predator]

0.8mm was always good for me

[Remix-]

Yeah, it's all sorted. Thanks for the quick response guys

[R31 POWER]

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

[hako]

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]

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]

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

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

[WazR32GTSt]

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  

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]

i'm using a 1mm gap set of champion coppers on my N/A and so far no missing.

[dnb]

definately the 1.1 people .i have an rb30 and used a 1.1mm gap untill i hit 220rwkw on 18psi(t04).then it started to break up a bit.i gapped them to .8 and it run fine,but lost a little power.i now run a cdi ignition and use 1.1mm gaps again making 250rwkw

[R31 POWER]

Interesting.

[funkymonkey]

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...