Do I really need 6 heat range spark plugs?

[Cubes]

I'm running 15.5 PSI without a fuel pressure reg bleed kit.

Hence it runs a little rich up top.

With 15psi without the fuel pressure reg bleed kit the best power I had out of it was 156rwkw.

Since then I've done a few little things like increase boost by .5psi and set a scramble at 15.5psi in manual mode to bring the boost up a little harder with the EBC.

I've also slapped a 100mm CAI in to the standard air box.. Lots of cutting

Last set of plugs I had these BCPR6E I think.. The ones with the V groove.

With the 6 heat range I did notice a little rougher idle only ever so slightly. I'm not sure if its due to coppers instead of Plats or if its just the heat range being a little cooler.

What I need to know is can I get away running the above setup with the standard plugs but a smaller gap for example 0.9mm?

I don't want to risk blowing a little bit of porcelin off the spark plug due to detonation because not enough heat is being removed from the combustion chamber. I could quite confidently say good bye to the ceramic turbo.

[rev210]

The gap on the 6's can be taken down to 0.75mm.

I'd lean towards getting some 7's working tho'. The gap could be opened a little wider say 1.1mm to start and then depending on the top end response closed down to 0.9 or 0.8mm. If they work out well invest in some platinums of the same spec and take the gap out 0.05mm more.

The thing to check on is the 'regular driving' aspect of the colder plug. They will be fab up in the higher rpms but if the gap is a tad small then they will foul on low throttle stuff.

It's not a bad thing to have a test of some colder range plugs with the intention of using them on performance events only.

[rev210]

I'm about to go to 7's myself as with the exhaust cam on retarded timing the cylinder temps are up and the 0.75mm 6's are getting 'cooked' with the timing advance I am running . I'd rather try and keep as much of the advance as I can and a colder range plug helps a little.

[Cubes]

I've been running these 6's for close to 30,000kays now...

I'm starting to only just notice a little bit of the typical bad plugs problem..

It will be used for a lot of light throttle and the od traffic light run.

Driving 5km's to uni and back not to mention driving around the campus from car park to car park..