pete mcrash

iTrader: (1)

.........stu (msd) said something in a post the other day about wasted spark system and i was wondering if u have to use a smaller plug gap to prevent it "blowing out".....t38, t4, gt30,35 etc.............ta

rapidcossie

Generally you have to use a smaller gap as the boost increases.

Going to a coil pack increses the strength of the spark and allows you to run larger gaps.

pete mcrash

iTrader: (1)

but is it "the bigger the better"...........

rapidcossie

bigger gives smoother idle a smoother drive compared to the smaller gaps.

Cant say I ever noticed the differences TBH

Rs1

iTrader: (1)

The bigger the gap you can get it to jump the better but with all things there will have to be a compromise. The strength of your ignition system will determine ultimate gap size. Generally old systems(points, 1st/2nd HT setups) will have a smaller gap, coilpacked bigger then cdi's geet fucking huge gaps.

Kverna

iTrader: (1)

Norwegians on bcr8es(ngk) usually gap's their to 0.6mm. But when fitting aftermarket ecu's they tend to go back to 0.8 for smoother driving on low speeds

Oranoco

i run a .28 gap on my A4 as advised to me by a VAG tuner. Seems to work ok.

tabetha

I'm running 1.0mm with no spark problems, drives better as well since I opened the gaps up from 0.65mm, but has given it a tendency to shunt a bit below 1500rpm in top which it didn't do before, but has not been fully mapped yet due to duff tps).
I am not using any external ignition amps though, so might be slightly different because of this but wouldn't of thought so.
tabetha

jb fletch

iTrader: (1)

I'm on a GT35 with IK31's from Stu @ MSD & run .7 no probs @ 1.9 bar !!

On my old plugs, the ford cheap ones that everyone uses it did feel "pluggy" on .6 plug gap.

jb