Spark plug info

[Saabman]

This may well be a complete load of rubbish but..... I once read when running a tuned car and driving hard the injectors are slower to react than the ecu wants them to act causing fuel to be sprayed onto the plugs when no fuel is required for example when changing gear at high revs, now apparently as the platinum tip plugs only have a small electrode the fuel can stick/pool on the tip and stop them firing or limit it, but because standard plugs have a bigger electrode that heats up any fuel sprayed on them is evaporated so they contine to fire correctly.

[sean treacy]

uum,food for thought that saabman,thats a new one to me but not beyond the realms of possibility.will be interesting to see if anyone else has any thoughts on that.

[phoenix]

Sounds like a flawed theory... apart from providing the spark, one of the other things plugs do is conduct heat away. The electrode on the platinum plugs is much smaller than regular ones, so if anything it would be hotter and thus more likely to burn fuel. But then agian they are all categorised in heat ranges to take care of this

But... how does this reconcile with the fact that a turbo car in hard driving mode will be mapped to run rich i.e. more fuel than can be burnt anyway...

If anything, it strikes me the risk might be that the hotter electrode temperature might cause pre-ignition, so if you're runnig na tuned car, best off to run a colder plug, regardless of whether it is platinum or regular.

[JTC]

I run BCPR7ES-11 re-gaped to .9mm on all my tuned Saabs as recommended by Lord Noobtune.

The theory is by closing the gap by .2mm gives a fatter spark, I change them whenever I do the oil & filters, normally around 5k miles on the 95Aero 19t with 342bhp and 500nm same on my 93og trackcar with 466bhp, I get fewer knock lights on T5. On T7 cars its alledgedly better for the DI.