Spark plugs, right for Supercharged Boxster ???
 

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.

"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, :cheers:
M

Maybe he means Yridium bicantizine which is an active ingredient in Ketracel-white.
Of course it's only available in Deep Space 9s world :P

Thanks again for your reply,

Interesting about the heat indexes and its relation to a the bump in HP. TPC, my supercharger kit manufacture, claims about 100hp gain, I have my reservations about these kinds of claims, but I have seen dyno readouts and, well, that’s what it looks like.

With that said, Turbo & superchargers by nature produce a heated air charge (thus the use of intercoolers in many of these apps.), Throw in the Boxsters 11.1 compression ratio & you’ve already got a recipe for detonation. So ya, a hotter plug will only add to the lethal mix.

Logic, anecdotal evidence*, advice of TPC and an installers suggest you don’t want platinum or iridium , throws more heat into mix. Also, as I under stand it, the heat is not very uniform and for some reason it further adds to the potential for detonation. The downfall of these setups is detonation, and they have been know to blow as a result.

Yiridium, spelled it wrong, meant “Yttrium”. It exists**. Gimmick, I don’t know, irrelevant, just seems like it might be a little to hot ***. But you tell me if you don’t mind, you’re obviously quite up on these things. I am dying to get on with this thing.

Thanks again, PK

Oh ya, the pepole in the know jut say use OE p[lugs, I'd be more comfortable with your advice, ratcheting the heat range down.


FYI

* http://www.renntech.org/forums/index.php?showtopic=14269&hl=heat+\spark+plugs\ (3rd post)

** http://dictionary.reference.com/browse/Yttrium
http://www.boschautoparts.com/Products/SparkPlugs/Super.htm

*** http://www.boschautoparts.com/NR/rdonlyres/C77B3446-232B-4AEC-AFA9-AD05F2A0A2AD/0/DesignationCodes.pdf
http://www.boschautoparts.com/NR/rdonlyres/7F3B3235-87DC-497B-A7D9-FBBAD66D08CB/0/PlugHeatRange.pdf (Dosnt explain what it low, medium, and high heat ranges relate to on the other identification chart above) considers "

Thanks for sticking up for me, its actually "Yttrium". :) http://dictionary.reference.com/browse/Yttrium

Plugs are here:
http://www.boschautoparts.com/Products/SparkPlugs/Super.htm

More iinfo in my other post if you care

Regards PK

http://986forum.com/forums/performance-technical-chat/7067-supercharger-installation-2.html

Near the bottom of this thread mentions plugs for the SC install. (i expect you've read it but incase you haven't).

THanks, I have read that thread in bits and peices a number of times, wanders a bit so I didn't notice anyhing about plugs, I'll look again.

Thanks!

PK

4:23 pm update: Pretty much what they told me, got hung on the yllium...bla..blaa stuf, but there OE so I'm putting them in, good thing to because what was in there were pretty "untorqued" platmium+4's, no good by anybodies standards for sc applications.

PK