This thread was saved without dates. "Around Sep 2004" is estimated from neighbouring threads.
i have an 8 plug head but am only running 4 sparkies though the one coil and dizzy, as do al uk s12's but im wondering what advantages i would get from getting the other 4 sparking are apart from emissions and also how can i get em going?
the only advantage is if you wire the other 4 to fire all the way up to redline as the other side does
how can i do this then?
basically take the signal wire from the ecu that goes to the main coil and just tap it into the second coil that will keep it firing all the way to redline
You're gonna need an 8 plug distributor cap and another coil as well.
questions?...wheres the signal wire and what color is it, and which one is the main coil....also what guage wire is recomended for this. sorry for all the questions :neutral:
ok cool. 8 plug dizzy cap hmmm.
il go speak to nissan
yup let my know which is the signal wire. if poss but im sure il find it eventually.
ive got a spare coil from my old s12 so thats sound.
is that all i need to do then?
8 plug cap swapped for my 4 plug one and fit my other coil?
you'll probably need a new rortor since yours probably doesnt have a contact for the other 4 plugs that the 8plug dist's have
why run 8plug?
the only "advantage" to an 8plug setup is you get better emissions.
Not true at all
If you look at a SOHC CA head, you'll see this
http://img.photobucket.com/albums/v228/mr200/200sx/swirl.jpg
notice how the plugs are not in the middle of the chamber?
What this does is create a perfect environment for hot spots, due to bad flame pattern. You're igniting the mix from the side, rather than in the middle, so you run a big risk at high boost of detonation.
By running both plugs all the time, you'll get a better combustion, which will keep you from detonating.
Plus, if you're running higher compression or boost, you could run into problems with the spark being able to jump the gap. With the 2 plug system, you have a backup spark. If one can't jump, the other might. That helps with preventing misfires which can destroy sensors, exhaust systems, foul spark plugs and cause a poor running car. I'd say for such a small amount of work, and for something that takes no power away from the engine, it gives a safety layer.
yup thats what i was thinking. if ive got the plugs sittning in there not doing anything i may as use them. so u recon i need a 8 plug rotor and dizzy cap then from nissan. is the distributor itself the same?
any idea which wire it is i use from the ecu?
ya just the cap and rotor is all you need..
cheers people!
il let ya know how it goes
My understanding is that because the extra plugs complete the combustion process (2X Flame fronts) they can give an increase of 20% more horsepower than if you use only 4 plugs. Some American Muscle car engines from the 70's used the same idea but because of the expense in terms of changing plugs and leads the design was dropped... And in the US because of emissions...