Spark plug gaps with aftermarket ignitions?
 

Anyone have any first hand experience with setting spark plug gaps using aftermarket CDI units (MSD or Crane) in a forced induction application?

Please see:

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/326382-plug-gaps-aftermarket-cdis.html#post3200373

I'm not going to comment on my gap as it's not a turbo like yours. Greater combustion psi demands greater spark energy vs mine. The greater the load on our close dizzy cap contacts the greater the chance of a crossfire among them. I know nothing of turbos.

i'm only good for suggesting you have very good CD positive and negative with dielectric.

Thanks Ronin. In natural aspiration applications, plug gaps of 0.040-0.045" can be used, but in forced induction configurations, obviously the plug gaps have to be reduced to reduce the likelihood of flame blow-out.

The honda ricer guys who run 19+ psi boost, set their gaps to 0.029-0.030", so I guess that may be a good guide for me.

The factory recommends 0.6mm to 0.7mm for stock 930 turbo's with stock boost and ignition. With aftermarket CDI, I should be able to open up the gap by up to 0.005", so that would take me to ~ 0.032". Hopefully even with higher boost.

I was just hoping someone on this board would have first hand experience with these things :confused:

In your aplication I'm not sure, but with the NA stuff .45 is too much. With an MSD unit and the gap of .45 the rotor has a tendancy to burn out.

call the manufacture. they know their system best and what it can do.