Spark plugs, right for Supercharged Boxster ??? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

pk2 · 10-13-2007, 12:48 PM

Quote:

Originally Posted by meerzee

"yridium?" doesn't exist. ...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

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 "