Forced Induction Spark Plug Gap.

I was told by engine gurus many moons ago that if you convert any vehicle to forced induction, two main rules should be followed:

1) To prevent / reduce the chance of detonation, a colder temperature spark plug MUST be run. Usually start with a two or three step colder plug and can work back to a one step at a time until you hit the correct heat range - you can always air on the side of safety and run a colder plug, running a hotter plug will only lead to problems. Run a set of plugs for a while, pull them and read them (lots of gray, black soot-like powerder or sometimes fuel fouled - plug too cold, if plug look white, shiny, blistered, sparkles like a diamond - plug is too hot).

2) To reduce the tendancy for the spark kernal to be blownout, reduce the spark plug gap. How much will depend on the plug and boost levels. Try stepping the OEM gap from 0.044" to 0.035" to start and see how that runs. Adjust gap until max power and drivability is achieved. Gap closed up too much will run as badly as a gap that is too big.

Plug wise - they say stick to plain single electrode plugs (ie copper plugs). You'll burn up a few testing out some thing and getting the tune straightened out. Fine-wire plugs like the OEM Iridium on the VVT-i 1ZZ-FE Corollas are suited for high RPM N/A engines - they don't recommend them for boosted apps, though I've seen people run them just fine.

As a little tidbit - old drag car running on alcohol - the sparkplug gap was between 0.010" to 0.005".

simple solution = ignition amplifier