Spark plugs, right for Supercharged Boxster ???

[meerzee]

"yridium?" doesn't exist. So, I don't know what you are trying to say. There is no substance, element, nor rare earth precious metal called "yridium" unless it is just marketing rubbish. Why would Iridium be considered a "no-no", it is actually a premium choice --- offering something in the neighborhood 600-1000x stronger and harder than platinum, superior conductor and probably one of the truly amazing rare earth metals around. I think the best choice would of course be a plug mixture of center E being iridium and ground E being platinum, the only consideration would be the heat ranges of such a combo on a modified engine and its specific requirements. Those rare earth and superior conductors might actually run too cold for your modified powerplant to enjoy and not all plug makers consider every single custom decision by modders.

In any case, the old racing adage was always 1 heat range cooler (for the optimum combustion chamber temperature) for every 75-100HP increase in modification.
Also remember that heat ranges are different between manufacturer and definitely between domestic and foreign. For example, NGK, the higher the #s, the colder the plug (where you want to be and I know am I not a BOSCH expert so check first) --- domestic is opposite higher is hotter (Champion, AL) - REMEMBER TO ALWAYS error on the side of running too cold a plug than too hot... So, figure out the anticipated HP jump, and if in the range of 100HP or less, go 1 plug range cooler for foreign plugs from your baseline OEM plug temperature range. --

Hope this helps,
M

Originally Posted by pk2

Hi, question about sparkplug heat and superchargers, what to much?.

I’m installing a TPC supercharger in my Boxster tomorrow (hopefully). There’s a spark plug which will become inaccessible & require removing the blower to replace it in the future, I’d like to replace the plugs before I put the blower in.

Several people familiar with this setup recommend stock plugs, definitely not platinum. I read somewhere it had to with the heat producedv and its distribution. I bought what were supposed to be OEM plugs; “Bosch Super plus (FR7LDC+)”.

The number indicates there heat index (?) a “7”. I thought I read “4” was Ideal for superchargers in this application.

Any body with experience, suggestion, etc?

Thanks, PK
P.S. my "O.E" plugs have yridium (yes, with a y) with copper cores. Iridium (with I) is supposed to be no no either.