Oh NO! Not another plug choice thread!

[rev210]

Thats right it's another thread on plugs!

I have a question about plug choice for those who are reving the engine to a peak power around 7000rpm on the stock turbo:

What plugs have you tried against what you are running and are happy with now?

I have 6ES units at 0.7mm gap, but since I have a S-AFC I was thinking of going to 7's or 8's with a larger gap.

My old rule of thumb for every car from rotory to V8 is 6's for 6000rpm , 7's for 7000rpm and 8's for 8000rpm etc.

For my old ported chooker it was 6's for traffic driving (don't fowl easy) and 9's for spirited driving.

[Xeron]

If u were making more power over stock u'd want to decrease ur gap no? .7 should be fine either way, but i wouldn't increase it.

And i think the rule from most plug companies is 1 heat range for every 75hp, or around there anyway.

[rev210]

Xeron,

Thanks for the input.

The gap can be opened up on a colder range of plug.

The 75HP thing isnt right but, thanks again.

[Steve]

Rev210, I am using BCPR6ES gapped at 0.8mm. They seem to do a better job than the stock ones that were in there. dont have any probs up to 7250rpm @1bar boost or pulling from low revs in a high gear. Idle quality is good and starts well. I am very pleased with them.

'For my old ported chooker it was 6's for traffic driving (don't fowl easy)'.....hehehehe dont know if a pun was intended, but I found it amusing anyways:)

[rev210]

Steve,

Pun intended.

the 6ES is what I have at the moment, gapped to 0.7mm (0.8mm is not as good with the timing I run). They are a pretty warm plug.

The 7ES equivilents I have in the form of Auto-lite racing plugs proved a better option for higher rpm use, I had them gapped to 1.1mm. The only problem with them was that I had them on the stock ecu with fewer mods than I do now. The plugs became fouled at the lower speeds I used 'around town'.

[Steve]

Originally posted by rev210

.....

The 7ES equivilents I have in the form of Auto-lite racing plugs proved a better option for higher rpm use, I had them gapped to 1.1mm. The only problem with them was that I had them on the stock ecu with fewer mods than I do now. The plugs became fouled at the lower speeds I used 'around town'.

Isnt this the problem with going colder - they work at a higher rpm and better for bigger hp but you get a trade off. Perhaps you could

a. Change them frequently....

b. Get the car down to the plex more often

c. Driving around in first - only in built up areas of course.

[Xeron]

hrm i cant remember what the figure is, it could be 150, too much beer in my head lately.

The way i understand it is, a colder spark plug will remove more heat from the combustion chamber, 70-100 degrees more quoted from NGK. What this means is, if your running too hot a plug, it will retain too much heat and cause detonation in your engine. Too cold a plug will foul quickly as it wont remain hot enough to burn off deposits.

A larger gap makes it harder for the ignition system to throw a spark over this gap. This can cause miss fire at higher rpm, so if ur running ur engine at a redline higher than stock, and ur experiencing missfire at wot, u might want to try dropping the gap .1 or more.

Hope i made more sence now that im sober